The Engineering Projects

Introduction to Surface Mount Technology

Greetings and welcome to today’s lecture. Today, we are going to focus our discussion on the Surface Mount Technology of PCB components mounting. It's our 8th tutorial in the PCB learning series and is going to be a very interesting and interactive class. In Surface-mount technology, SMT components(having small pads) are placed on the surface of the PCB board and their pads are soldered on the same side of the board.

As we discussed in our last lecture on Though-Hole Technology, there are two main methods used to mount components on PCB boards. We studied THT in the last lecture and today, we will focus on  Surface Mount Technology (SMT), we will discuss SMT classifications, types, applications, advantages and disadvantages in detail.

In the beginning, a breadboard was used to hold the components together. This had a major disadvantage because components could pull out as they remain loose in the breadboard, hence giving a hard time to designers, especially in the case of complex circuits. The engineers came out with a solution called the PCB board. Initially, Though-hole technology was used to plug components into the PCB board. Later on, with the invention of SMT components, surface-mount technology came into existence. So, let's have a look at SMT in detail:

Introduction to Surface Mount Technology

• Surface-mount technology(SMT), initially called planar mounting, is used to mount components on the surface of the PCB board.
• In Surface-mount technology, SMT components are used, which are quite small in size and have small pads, instead of leads/pins.
• In SMT, components are placed on the PCB board at their required positions and their pads are soldered with the copper markings on the board.
• Unlike THT, the component pins in SMT don't cross the PCB layer, they are soldered on the same side of the board.
• SMT is the most popular method that is being employed in today’s PCB manufacturing process because it can be purely automated hence increasing the number of boards produced and also saving on production time. With this method, the cost of the PCBs was reduced drastically, if you are doing mass production.
• As the name suggests, the components are mounted on the surface. So, there are no holes for the components mounting as in the THT method.
• Initially, the process was done manually but today it is done by the use of advanced machinery, thanks to the technological revolution.
• SMT discovery came in the 1980s when companies were struggling with the high demand for printed circuit boards. Fab houses had started shifting to mass production of the boards and therefore they had to introduce new methods of PCB assembly and mounting to speed up the process.

How to place an SMT PCB order?

There are many online PCB companies available, where we can place orders for PCB with surface mount technology. Let's take the example of JLCPCB Fabrication House, one of the leading PCB manufacturers, which offers top-quality products.

• First of all, open this JLCPCB SMT Assembly Page.
• Here you can see, it's quite easy to place the SMT order.
• First, you need to Upload the PCB Gerber Files, as shown in the below figure:

• JLCPCB has a remarkable online PCB order tracking system, which keeps you aware of the current situation of your PCB order, shown in the below figure:

• Once your SMT PCB order gets completed, you will receive it at your doorstep.

SMT Manufacturing Process

• Using the assembler, solder paste is applied on the parts where the components will be placed. The solder paste placement follows the guidelines from the design.
• Use the stencil or the solder screen to ensure that the solder has been placed in the exact required positions.
• Sometimes, stencils and assemblers might not be that accurate and it's the operator's duty to inspect the solder to ensure that it has met the required standards.
• Depending on the defect, either the assembler corrects the defect or will remove it and reapply afresh.
• The process of inspection is very important because it will determine the quality of the solder at the end of the process, hence affecting the overall functionality of the board.
  
• After inspection, the assembler will place the components accurately following the designs given by the designer. Originally, it was done manually by workers with hand tools. Today, pick-and-place machines have made work quite easy, accurate, and fast.
• After placement, the components are soldered into pads with the solder gun. Here, the board undergoes a reflow process in which it is passed through the furnace to remelt, liquefy and finally solidify the solder at component joints.
• Special devices used in the process of SMT are called Surface Mount Devices.

Types of vias

The SMT employs the use of vias in order to connect components with the PCB board. There are three types of vias that are employed throughout the process i.e.

1. Blind vias.
2. Through vias.
3. Buried vias.

Through vias

• This one connects all the layers of the PCB board by passing through all of them.
• Mostly Through vias are used for the power pins i.e. ground, Vcc etc.

Blind vias

• Blind via connects any of the external layers to neighboring two or more layers of the PCB board but won't go through all of them(as that will be Through vias).
• Blind vias are of several types as listed below:

1. Controlled depth blind via
2. Photo defined blind via
3. Laser drilled
4. Sequential laminated blind via.

Buried vias

• Buried via connects any two or more layers of the PCB board but won't touch any of the external layers.
• As the name suggests, it remains buried inside the external layers of the PCB board.
  

Machines used in SMT mounting

Here's the list of machines used in the SMT manufacturing process:

PCB Drilling Machine:

• Even though I said that the SMT components are mounted on the surfaces, so there's no drilling but remember that we discussed vias, which are required to create a connection between layers of the PCB boards.
• These vias are very tiny holes drilled into the board layers and are done by the drilling machine.

Wave Soldering Machine:

• This is used for the soldering of components on PCB pads, essential for the mass production of PCB boards.

PCB Brushing Machine:

• We have discussed the vias drilling, so after the drilling process, we have debris deposited on the PCB boards.
• This debris is removed by the PCB brushing machine.

Pick-and-Place Machine:

• Pick-and-Place Machine picks up the components, rotates them in the required direction and places them on the PCB board.
  

PCB cleaning machine:

• It does all the necessary cleaning of the board.
• It also ensures that the board is dry and free from any form of moisture.

Reflow oven:

• It contains a lot of burners and is used to smooth the soldering process.
• There are three types of Reflow ovens available:

1. Vapor Phase Oven.
2. Infrared Oven.
3. Convection Oven.

Now, let's have a look at the different types of Surface Mount Methods:

Types of Surface Mount Technology

Type I

• Only SMD components are found in this type of PCB board.

Type II

• Active surface mount devices and DIPs are located on the primary side of the PCB while the surface mount chips are on the secondary side of the board.

Type III

• In this type, you will find passive SMCs on the secondary side of the board while the primary side is made of the DIPs only.
• It contains only discrete mount components and they are all mounted on the bottom side.
• The discrete components include; transistors, resistors, capacitors etc.

Applications of the SMT components

With SMT technology, it has become possible to produce very compact and small-size boards, since machines are used to pick and place the components. Therefore, SMT technology has numerous applications in real-life fields, few are as follows:

1. Smartphone Evolution: Smartphone boards are quite small in size but complex in design because mobile phones need to be thin and light therefore, this technology has aided a lot in the evolution of the smartphone industry.
2. Computer and laptop motherboards: It has helped in the production of ultrathin laptops, tablets and computers.
3. IoT Devices: With SMT technology, IoT has moved to another level since the production of embedded boards become easy and fast.
4. Involved in the manufacturing of communication and telecommunication equipment i.e. Bluetooth, WiFi, Ethernet devices etc.
5. Medical devices in aid of health screening.
6. Finds applications in the transport area i.e. drones, space exploration equipment etc.

Advantages of the SMT components

1. They have very low RF interference because they don't have leads.
   
2. It takes lower packaging materials and this is due to the advanced manufacturing that is being involved.
3. If SMT boards are produced in panels(We will cover penalization in upcoming chapters), the process makes it easy to transport in bulk at a reduced cost.
4. The production cost has been drastically lowered compared to that of the THT product of the equivalent magnitude.
5. Component failure is very low due to the consistency of the fabrication process involved.
6. Less expensive process and very economical due to the use of more advanced technologies like PCB Panelization and pick and placing mechanism.

Disadvantages of the SMT components

1. It is not the best method to mount high-wattage components because such components dissipate a lot of heat that may end up damaging the PCB board.
2. This is made up of very tiny components and therefore if there is any damage to the circuit, it is very complex to repair/debug the board as compared to the THT components. This means time-consuming in repairing and also very expensive.
3. This type of board cannot be used in a place where rough holding is involved.
   

So, that was all for today. I hope you have enjoyed today's lecture. In the next lecture, we will have a look at the difference between these two mounting techniques i.e. THT vs SMT. Till then, take care. Have fun !!!

THT vs SMT

Hello everyone, I hope you all are doing great. Today, we are going to share the 9th chapter in the PCB learning series, where we will have a look at the difference between Through-hole and Surface-mount technology.

In our previous lectures, we studied both THT and SMT methods separately and have seen that both are used for components mounting on the PCB board. So, today, we will have a look at the difference between the two techniques. So, let's get started without wasting any time.

Through-Hole vs Surface-Mount

Let us know have a look at these differences and get to know the way forward when it comes to the process of component selection whether SMT or DIP.

Definition - THT vs SMT

• THT stands for through-hole technology.

In Through-hole technology, components are mounted by the use of holes that are systematically drilled through the layers of printed circuit boards. the components have long leads that are properly fitted in the holes and soldered.

• SMT method stands for Surface Mount Technology.

In Surface-mount technology, components are mounted on the surface of the printed circuit board. This is the most recent method employed in manufacturing of printed circuit boards.

How to Manufacture?

There are many online PCB Manufacturing companies, where you can place your SMT or THT orders. For example, let's talk about JLCPCB Fabrication House, they offer both THT and SMT fabrication. You can place your order on the official site of JLCPCB. They have an excellent support team, so while placing your order, you can discuss your design with them and they will guide you completely.

JLCPCB offers competitive prices as compared to other PCB houses and delivers quality work within the assigned time limit. They also offer seasonal discounts, so if you are a regular PCB designer, you should subscribe to JLCPCB.

Component Mounting

Through-hole Technology:

• In Through-hole Technology, DIP components are used having copper leads/wires called lead wire terminals.
• These leads are used to connect the components with copper tracks on the PCB board.
• These leads are inserted in the drilled holes on the PCB board and are soldered from the back side.
• The extra leads are then trimmed off using a cutter.
• A DIP component having two leads is shown in the below figure:
  

Surface-mount Technology;

• In Surface-mountTechnology, SMT components are used having copper flat terminals(called pads) instead of leads/wires.
• These SMT components are placed on the surface of the PCB board as mentioned in the design files and the flat terminals are soldered with the pads of the PCB board.
• An SMT component is shown in the below figure:

Manual vs Automatic Process

Through-hole Technology

• Through-hole PCB boards can be assembled both manually and automatically(with the help of machines).
• Normally manual assembling is preferred in THT boards.
  

Surface-mount Technology

• As the SMT circuits are complex in design, thus it involves the use of sophisticated systems to ensure that the process is accurate and error-prone.
• Pick-and-place machines and stencils are used in the SMT process.
• Manufacturing SMT PCB at home is too difficult so automatic processes are recommended in this case.
  

Stencils

Stencil is a modern technique to place solder paste on a bare circuit board. This paste forms the deposits on the board that is used to hold the components in place.

Through-hole Technology:

• The through-hole technology does not involve the use of stencils since the components are mounted in holes and are soldered on the other side.

Surface-mount Technology

• The surface mount technology uses stencils for the process to be smooth.
• Solder paste is poured through a stencil on the PCB board and then SMT components are placed on it.
  

Vias

Vias are small drilled holes between the PCB layers to electrically join traces of the circuitry.

[TEPImg11]

Through-hole Technology

• For the through-hole technology, vias are not that necessary since the components are connected through the holes to the other layers of the boards.

Surface-mount Technology

• The surface-mount devices employ the use of the vias to connect between layers of the board. Since components are mounted on the same layer, it is very necessary to employ the vias to interconnect between the layers of the PCB board.

Debugging

• Through-hole technology mounting components and boards are quite easy to debug/repair, that's why, THT is used when a prototype or testing is required.
• Surface-mount technology components are quite difficult to debug/repair because they are very small in size.

Soldering

Through-hole Technology

• Wave Soldering is used in THT boards.
• It's an in-line soldering process that treats the solder with flux.
• The solder is melted after getting heated and then immersed on the PCB board.
  

[TEPImg12]

Surface-mount Technology

• Reflow soldering is used in SMT boards.
• In reflow soldering, a solder paste is used to mount components temporarily on the board by the use of the pads after which the entire design is preheated.

[TEPImg13]

Component Types

• Through-hole technology uses lead capacitors and resistors, DIP and GPA components.

• The surface mount technology uses LCCCP, SPOIC, QFP, BGA, SOT, LCC, chip resistors/capacitors etc.

Assembly Density

• Through-hole technology is used when a low density of components is required.
• Surface mount technology is used where a high density of components is required.

Solder Joint

Through-hole Technology

• For the through-hole technology, the solder joint connects the component lead to the board through a hole drilled on it.
• The solder is applied on the lower side of the board and the upper side is filled with the flux.

Surface-mount Technology

• For the surface mount devices, the board is first spread with the solder paste, after that components with pads are placed accordingly on the soldered points and then the solder is melted to fix the components on the board.

Cost of Production

The cost of production for the two methods varies, normally determined by the type of manufacturing process and the components used.

Through-hole Technology

• Through-hole technology proves to be the most expensive. when it comes to initial production because it involves drilling holes to mount the components.
• But when it comes to routine maintenance of the THT boards, the cost is relatively low since it is very easy to replace any component on the boards. THT is easily repairable.

Surface-mount Technology

• Surface-mount devices are cheaper when it comes to initial manufacturing.
• The process is purely automated hence saving oh human labor costs.
• Also, the process does not involve the use of holes in the mounting of the components hence reducing costs.
• The boards are produced in bulk through the process of PCB panelization, this also lowers the cost of production of the boards.
• Now, there is one challenge with this type of board, the maintenance cost is too demanding. You will need a lot of expertise to change any faulty component. Some of them cannot be changed since they are so tiny. Therefore, in most cases, if the board has a problem, you might end up buying a new one hence it is very expensive when it comes to maintenance and repair.

Applications

Through-hole Technology

• Through-hole technology is preferred in hobbyists and academic projects, because of simple circuits to design.
• THT Boards are also used in areas where strong mechanical strength is required such as in military equipment and equipment with high vibrations. This is because their soldered joints are mechanically strong.

Surface-mount Technology

• Surface-mount devices are preferred in the industry sector where commercial products are designed because SMT is cheap, lightweight and small in size.
• The manufacturing time of SMT boards is quite low, especially in mass production, because its manufacturing process is purely automated.

So, that was all for today. I hope you have enjoyed today's lecture, let me know if you need any help with it. Thanks for reading.

Introduction to Through Hole Technology(THT)

Greetings and welcome to today’s lecture. It's our 7th tutorial in the PCB learning series. In our previous lectures, we have studied the two main types of PCB i.e. Single-sided and Double-sided PCB. Today is going to be a very interesting and interactive class about Through Hole Technology(THT), which is applied in the process of designing printed circuit boards.

A PCB board has a properly designed circuit on it and it's composed of connecting traces/paths and various electronic components. The electronic components are mounted on the board in two different ways i.e. Through-hole and Surface-mount. We will cover Surface-mount in our next lecture and today, we will discuss how to mount components on PCB boards using though-hole technology.

So, let's get started with Through-hole technology:

Introduction to Through-Hole Technology of PCB Design

• In Through-Hole Technology(THT), small holes are drilled in the PCB board to mount the components.
• The normal-sized components(unlike SMD components) have long copper leads/pins and are plugged into these drilled PCB holes and soldered from the other side. The extra leads are trimmed off.
• In through-hole technology, components are placed on one side of the board and soldered on the other side, where the copper foil is present.
• Through-hole technology is normally used in single-sided boards.
  

History of Through-hole Technology

• THT is the oldest among these PCB components' attachment methods.
• For quite a long time, it remained the standard method to use in the PCB assembly process.
• In the 1980s, when the surface mount technology process was introduced in the field of PCB assembly, designers thought that the THT method will become extinct but that is still not the case.

Why do we still need THT?

• The surface mount technology, being advanced had many advantages over the old Through-hole technology but because of low cost, THT is still operating.
• Some high-power components that required strong connections could not be fitted by the surface mount process, THT is the only option that could be used in such a process.
• For example, the connection of the terminal blocks, power jacks and other power connectors can not be done by any other method apart from the THT.
• Also, equipment working in places with high temperatures and vibrations can only have boards that are connected through the through-hole technology.
• Therefore, while others thought that, the entry of the surface mount devices was the end of the through-hole technology, their thought was disapproved over time, as of today, through-hole technology remains one of the important mounting processes in the manufacturing of the PCB.

How to place THT PCB Order?

There are many online PCB Fabrication Houses, that provide Through Hole PCB board services. One of them is JLCPCB Manufacturing House, which offers this facility of mounting Through Hole components as well as SMT components, a sister company of EasyEDA. JLCPCB is a top-notch PCB Fabrication House, provides low rates for PCB orders.

JLCPCB has an excellent support team, so you should discuss your PCB order with them first. They will completely guide you and will give you the final price and time to complete it. JLCPCB provides a perfect product as per your requirements, a personal experience.

THT Process

• Drill holes on the PCB following the clients’ design.
• Holes have several specifications from location to diameter sizes.
• In the design folder submitted by the designer, there is a very specific file named drill file. This is the file that will give the location and sizes of the holes to be drilled on the boards accordingly.
• Select the components, that must have long leads and every component has its own specification. Components are mentioned in the BOM files, schematics and the GERBER files. If you go through the files, you will get the components to be used in the design, whether, THT or SMD components. THT components will be selected in this case.
• The next phase is to place the components on the board and ensure that their leads are on the holes as defined in the design. This process can be done manually by human hands or can be done by pick-and-place machines that have been designed specifically for this purpose.
• Ensuring that the components are in the positions described in the design to avoid any errors.
  
• Solder the terminals on the board accordingly. Soldering is one of the most important processes in THT PCB design.

• Soldering is done by use of the soldering gun which is of different varieties as shown below:

Initially, this process was done manually and was time-consuming, but today, due to AI technology, it has become quite simple and automated to design through-hole technology. An automated insertion machine helps in inserting the electrical elements into the drilled holes of the PCB before the soldering process starts.

Classifications of Through Hole Components

We have talked about the electrical components being placed on the PCB boards through the hole.s These components can be classified into two main types:

1. Radial-leads components.
2. Axial-leads components.

Radial-leads Components

• In Radial-leads components, all the leads originate from one side of the component.
• The components can be mounted either vertically or horizontally.
• Radial-lead components include capacitors, op-amp, power regulators(LM317, LM7805) etc.

Vertical mounting of Radial THT components

• In this case, the component is placed perpendicular to the board while the base is placed parallel to the board. Soldering is done on one side of the terminal and the other side is filled with flax.

Horizontal mounting of Radial THT components

• The component body is fixed horizontally as you can see in the image above.
• The leads exhibit a very nice bend and spacing. This allows the proper filling of the solder on the component hence forming the strongest bond.
• The component is free from vibration effects as it is well-fixed on the board.

The Axial leads Components.

• In axial-leads components, the leads appear from opposite sides of the component package.
• Axial components are placed horizontally over the PCB board and are strongly attached to the sheet.
• Common examples are diodes, resistors etc.

Vertical axial mounting method.

• One side of the mounting lead is long and allows room for its bending to achieve horizontal fixing.
• It has a strong mechanical joint as it can allow soldering on both sides of the board.

THT Components types

Single-ended

This is mostly used in integrated circuit embedded systems. Those ICs that have terminals on one single side are said to be single-ended THT components. See the attached figure below.

Double ended

Again, it is applied in ICs systems. Some IC for example the 8051 AT89C51 have pins that are arranged in two files each from its side of the length as shown below. The type of THT that will be used to fix them in the PCB is called double-ended THT mounting.

Pin grid arrays THTs

In this type of THT, the components have so many pins that are arranged throughout the component in a grid manner. See the example of such components below.

Applications of THT

• High voltage areas eg in the medical equipment. When high voltages are involved, there is a possibility of shorts and overheating of the components. Since this type of component mounting provides a strong joint, thus THT comes in handy.
  
• High mechanical stress devices eg military equipment. High stress, requires strong joints to avoid breakages. This can only be offered via the THT type of mounting.
• High power areas eg in the steam boilers. High power is accompanied by vibrations and magnetic forces. This type of mounting is good for such devices.
• High temperatures operating devices eg in the nuclear plants. High temperature means the possibility of high reliability. Hence, we can use THT as it can be easy to replace components in case of problems.
• Prototyping and testing of components since it is the most flexible method offering easy ways for replacement of components during the process.

Advantages of THT

1. The use of the THT method will ensure that you have a very strong mechanical bond between your components and PCB board.
2. THT-bound components have high resistance to wear and tear and this is made possible by the use of the large soldering deposits at the terminals.
3. The THT components are very easy to swap/repair, thus, best for prototyping works.
4. It is best suited for places where strong mechanical applications are needed such as aerospace and military equipment.

Disadvantages of the THT method of PCB components Mounting.

1. Due to the drilling of the required holes, the production machines have to be very accurate.
   
2. Drilling of the holes requires some additional time, hence THT method takes a longer time compared to other methods.
3. This method limits the available routing paths for the multilayer PCBs because the drilled holes have to go through the given layers.
4. The technology being used in the industrial mass production of THT is less reliable compared to other methods.

The through-hole technology PCB mounting is the best method to be used when manufacturing large PCB boards. It is best for mechanically strong component mounting and also the cheapest when it comes to doing testing and prototypes. It can't be extinct and it will never.

So, that was all for today. In the next lecture, we will discuss the second method of mounting components on PCB boards named Surface-mount technology. Till then, take care!!!

Manufacturing Process of Multilayer PCB

Hello! Readers, I hope you are pretty good. I am here with a new article to enhance your knowledge about advanced technologies. Today, we will have a detailed overview of the Manufacturing Process of Multilayer PCB. First, we will have a look at its basic definition, why there Is a need for this new type of PCB in presence of single layer and double layer PCBs. What are the merits and demerits of multilayer PCBs and pedagogy behind the construction process of these PCBs? Let’s start to take in all information about these PCBs. I try my best to deliver all of my research capacity for doing this job.

Introduction to Multi-layer PCBs

As to the name, it's clear that multi-layer PCBs are those which have several conductive layers over substantial material which is knowns as substrate. Unlike single layer and double layer PCBs which consist of one and two copper foil layers respectively, multilayer PCBs contain more than three lays on a single board.

Before discussing the multi-layer PCBs let put a throwback to What’s PCB. How are they classified and what are they used?

Printed circuit board (PCB)

The word PCB comes from a printed circuit board that consists of sleeky copper chips on it which are conductive. These tracks are linked with each other electrically.

How to Manufacture Multilayer PCB?

In order to manufacture a PCB board, you need to take the help of a PCB Fabrication company. There are many online PCB companies available. where you can place your PCB order on their official website. While placing your order, you need to select all your specifications/requirements and they will give you the cost and time to complete it. Let's place an order of Multilayer PCBs on PCBWay Fabrication House. PCBWay is a well-renowned PCB Fabrication house, provides excellent prices and discounts on first orders. Moreover, they have an excellent support team, ready to help you, 24/7. So, let's place our PCB order:

• First of all, open the official site of PCBWay(PCB Manufacturing House).
• Now, at the top, you will find an instant quote screen, click on the button to open the PCB Calculator page, as shown in the below figure:

• As you can see in the above figure, I have placed an order for a multilayer PCB having 4 layers.
• I have added a size of 100x100mm and have placed an order for 10 pcs of PCB.
• PCBWay has given me a cost of $139 for standard manufacturing and with shipping in America, the total cost is $166.

That's how easy, you can place a manufacturing order for PCB.

Criteria for classification of multi-layer PCBs

There are many ways by which we can categorize different types of PCB. Most commonly they are classified on basis of their layers , types of substructure material , conductive layers and rigidness of the boards, etc. Now put a little thought into describing these methods.

• Number of layers
• Type of base substantial
• Thickness of conductive layer
• Rigidness

Number of layers

This methodology divides PCBs into single-layer PCB , double-layer PCB, and multi-layer PCB . if PCB has a computerized structure on one side then it terms a single layer PCB. if they have a circuit on both sides of the board then it is termed as double-layer PCB but with the invention of technology and with the enhancement of our need we require complex electronic structures which take less space but do more than one task on a single device. Due to which we mounted more than two layers over a single board to form a multi-layer PCB. It has more layers and flexibility than two earlier PCBs which are single layer PCB and double layer PCB. Under the present rank of technology, we can form PCB having almost 32 layers.

Type of base substantial

The material which is mostly used in the preparation of PCBs is fiberglass, cyanate ester, polyamide, and polyester reinforcement. The substantially material should be

• Dimensionally stable under heating process
• Have good strength of attachment with another conductive layer
• Beneficial in electrical impedance
• Highly elastic

The thickness of the conductive layer

This method sort out the PCBs on the basics of consistency of copper foil and the breadth of conductor route onboard. The board ness of a copper layer may alter from 0.0014 to 0.0042. These factor combined determines the cross-sectional area of the board. Which in return decides how much current can a conductor carry.

Rigidness

For offering the reinforcement to the circuit which must have an electrical connection between them we require a rigid PCB. To furnish the rigidity, the thickness of the board must be almost 1.6mm. variety of substantial materials are used for this purpose.

Kinds of PCB

There are three kinds of PCB as given below

• Single layer PCB
• Double-layer PCB
• Multilayer PCB

Overview to multi-layer PCB

• If you are focus on the name of this PCB which is Multilayer it clear that it is a type of PCB which have more than two layers. In simple Words multilayer PCB have several conductive layers on a single board.
• They are favored in many elegant industrial tasks and motherboards etc.
• Most importantly where we need to save space we can use these PCBs for example in a digital camera, android mobiles even on compact disk.
• Multi-layer PCBs which are available now a day in markets have 4 to 8 layers.

Construction of multi-layer PCB

• Multi-layer PCBs area unit designed by connecting all the quantity of lays and material at heat and pressure therefore on take away any at bay air between layers.
• Organic compounds and staff are employed to stay the parts and different lays along.
• You have a choice in choosing a variety of materials like exotic ceramic, epoxy glass, Teflon, etc. to fabricate the PCB.
• The various prepreg and core layers area units combined and bear the lamination methodology happening at heat and pressure that helps to moderate the layer along. Later on, the PCB is cooled then it becomes rigid and solid board.

• The internal layers of multi-layer PCBs consist of special material which is known as prepreg.

What is prepreg?

• The lays of the healed panel in multi-layer PCB are freestanding by a sheet of B stage organic compound, which is termed prepreg. This layer aims to adhere to the rigid layer with each other and fixing the board between layers.

Problems faced by experts in manufacturing multi-layer PCBs

One biggest issue faced by manufactures while dealing with fabrication of multi-layer PCBs is drilling hole technology.

Technique for interconnecting layers on MLBS

We can make an electrical connection between components which present on several layers of multilayer PCB by using different methodologies which we are given below ;

• Through-hole via
• Through buried via
• Through blind via

What is via?

As we discuss in the previous article VIA is a vertical hole on board that is then filled with metal foil for interconnecting the component. Different modes of via to tackle this situation are elaborated below ;

Through-hole via

By using this technique we can join components of the upper side of multilayer PCBs

Through buried via

By using this pedagogy we can link the internal lays of multi-layer PCBs.

Through blind via

A blind via can link the topmost layer with internal layers of multilayer PCB.

Lamination method of multi-layer PCBs

• Internal layer gist, coating of B stage resins, and coating of atomic number 29 foil are used in the lamination process of multi-layer PCBs.

• Drilling of holes in the coating of substrate and core is utilized to line up them as they are stack aboard.
• For a four-layer PCB, we require a sheet of foil and a suitable range of woven glass cloth with epoxy resin.
• The stack of the panel is fabricated on a meaningful conductive plate and once it’s completed the plate becomes a valuable board.
• Now we heat this board under necessary conditions.
• The application of pressure, heat, and vacuum on board forced the organic compound to become flexible and consistent across core and foil surfaces.

Why do we need multi-layer PCB?

Here we discuss under which situation we preferred multilayer PCB over the other two.

• To tackle problems related to weight and volume which are commonly seen by experts during their works multi-layer PCB Is their solution.
• For a composite electrical circuit, multilayer PCBs are less pricy than a single layer and double layer PCB.
• Multilayer PCBs are help full in reducing the resistance problems in an electrical circuit and increase the chances of supply of current which in return increase the flexibility and demand of products.
• It increases the reliability of electrical circuits
• For a circuit that requires several numbers of interconnection multilayer PCBs are ideal. They allow high-speed performance.

Common mistakes in the manufacturing process of multi-layer PCBs

• Irregularities of electrical connections onboard are the biggest problem by which ones have to tackle.
• Delay between layers during bonding causes poor care in bonding. Other puzzling circumstances are discussed below.
• High resistance causes a big issue due to poor plating in holes.
• Inadequate tooling techniques.
• Due to high stuff of components into small available space causes an uninventive structure.

Key points to overcome these problems

To get better-fabricated multi-layer PCBs one should follow these steps

• The developer must be highly experienced and he must concentrate their attention on quality.
• He must have the strength to control the process.
• The board must be stocked in a bit of time and dried for almost 120 minutes at 120°C.

Advantages of multi-layer PCBs

There are many merits of multi-layer PCBs. Let’s start to grasp the knowledge about advanced technology rewards.

• We can tackle many problems at a time by using multi-layer PCBs.
• It offers less resistance and enhances power distribution between electric components on board.
• Multi-layer PCBs are less weight and have a small size which has adorable uses in advanced technology which becomes handy with time.

With the aid of multi-layer PCBs, we can have boards which although are small in size but are more compatible to tackle problems.

• Multi-layer PCBs are favored for the high-speed circuitry process.
• Multi-layer PCBs decreased the chance of EMI expelling which comes due to small loop area and high distributed capacitance.
• Multi-layer PCBs are highly persistent as they are configured at a High level.
• With the increments of layers in a single structure trim the size and become compatible to link more electronic components in the available space.
• Multi-layer PCBs are designed by high standardized fellowship therefore multi-layer PCBs are prefabricated.

Disadvantages of Multi-layer PCBs

As we know that there is some raw fact about everything. Multi-layer PCBs also have a demerit. The weakened point of multi-layer PCBs are discussed below;

• Multilayer PCBs require High expenditure. The manufacturing process of Multi-layer PCBs requires a heavy budget.
• Although multi-layer PCBs are very worthy due to their small size in advanced technology at the same time, It is not an easy task to tackle with an intensive circuit on a single board. A very careful mental focus is required while working with multi-layer PCBs.
• It is difficult to mend and retread the interconnection of multi-layer PCBs.

Applications of Multi-layer PCBs

Multi-layer PCBs have outstanding features. This worthy characteristic makes it popular for usage. Multi-layer PCBs have applications in household appliances, industrial works, wireless computing, ballistic capsule, and many other instrumentations. Multi-layer PCBs have distinguishing characteristics in the development of vast practical applications. Some applications of Multi-layer PCBs are illustrating below;

• Because of their small size, multi-layer PCBs are utilized in handy technologies like android mobiles, cameras, motherboards.
• Multilayer PCBs are used in signal transmission which requires more accuracy in processing.
• Multilayer PCBs are used in navigational computing.
• Multi-layer PCBs are used in holding the data safely.
• Multilayer PCBs are used in communicating technologies. The use of multilayer PCBs trims the size of new inventions.
• Multi-layers PCBs are used in challenging situations for the trial process of different instrumentations.
• For forecasting atmospheric conditions multi-layer PCBs are used.
• Multi-layers PCBs are used in the instrument which is utilized for observing the cardiac conditions.
• Multi-layers PCBs are Second hand in warning devices.
• Multi-layer PCBs play an important role in the fabrication of robotic space Vehicles designed to voyage the earth's orbit.
• Multi-layer PCBs are used in computed axial tomography scanners helpful to an analyzed brain tumor.
• Multilayer PCBs are used in roentgen ray instrumentations. These instruments tackle medical problems.
• Multi-layer PCBs are used in industrial systems for controlling purposes.
• Multi-layer PCBs are specifically worthy in technology associated with satellites, missiles, aircraft, and spacecraft.
• Even we can say that the building block of innovative conception is multi-layer PCBs. It becomes the need of fast, durable, flexible and valuable designs.

Conclusion

In the end, we conclude that there are more number layers in multi-layer PCBs than single and double-layer PCBs. Multi-layer PCBs have Unmatched properties, valuable applications but in the end, nothing is perfect each technology has some drawbacks like this multi-layer PCBs also have some drawbacks.

In modern computing, the demand for multi-layer PCBs is more than the other two PCBs.

• You always need to opt for which kind of PCB you would like.

 

That’s all for today’s article. I hope you've got enjoyed the article and build a grip on the understanding points. However, if you continue to face any skepticism concerning multi-layer PCB then please be at liberty to depart your queries within the comment section. I'll give a solution to those inquiries to the simplest of my data and researching skills. Also, give North American country along with your innovative feedbacks and suggestions you improve the standard of our work and supply you content in keeping with your wants and expectations. keep tuned! thanks for reading this text.

Introduction to Single Layer PCB

Hello friends, I hope everything's going well. Today, I am going to share the 13th chapter in the PCB learning series, where we will discuss the single-layer PCB in detail i.e. definition, construction, advantages, manufacturing, applications etc. So let’s try to absorb everything about the single-layer PCB:

Single-layer PCB overview:

• Just a quick recall, PCB stands for a printed circuit board having different electrical components connected with the help of pads and tracks of copper foil, incorporated on an insulating material(substrate).
• Single-layer PCBs have only one conductive layer of copper.
• The PCB board itself has a total of 3 layers in single-layer PCB other than the copper layer which are substrate, solder mask, and silkscreen.
• In the past, phenolic aldehyde was used as a substrate but nowadays glass fiber epoxy resin is used because of its flexibility with temperature variations.

Single-layer Definition

• Single-layer PCB refers to a printed circuit board that has only 1 layer of conductive pattern.

• Single-layer PCBs are simple, low-cost and can be designed at home.
  
• Different materials like glass fiber reinforced epoxy resin with copper foil and a paper mask having phenolic resin with copper foil are used in the manufacturing of single-layer PCB.

Pricing of Single Layer PCB

Now let's have a look at the pricing of Single Layer PCB. As Single Layer PCB is the simplest form of PCB, so it's quite low cost as compared to other PCB types. Let's take the example of JLCPCB Fabrication House, a well-renowned PCB manufacturing company, that offers competitive rates for PCB designing.

• We need to open JLCPCB official site and click on its Order Now page, as shown in the below figure:

• As you can see in the above figure, I have selected 1 for Layers, so I am ordering for Single Layer PCB.
• The size of the Single Layer PCB is 100x100mm and I have placed the order for 5 pcs of PCB.
• For this order, JLCPCB has given me a price of $2.00, so you can see it's quite cheap to design Single Layer PCB.

Construction of single layer

• In 1950, the first single-layer PCB was designed.
  
• The base material or substrate is made up of fiberglass and is compact in its sense.
• There is a copper layer that has conducting path for various competent on the boards above subtract. Needless to mention, different boards have different copper thicknesses consistent with your needs and demands, defined in ounces per sq. ft.

• On one hand, there is a solder mask layer on the top of the copper foil. The layer mainly protects the copper foil from insulating which avoids conduction in case direct contact happens with some conducting material.
• On the opposite hand, there's a silkscreen layer on the highest of all layers, which is especially in adding characters and symbols on the board, so it’s easy to have a far better understanding of the board.

Types of singles layer PCB

There are some types of single-layer PCB. We are going to explain them below concerning its manufacturing material.

1. Single-layer rigid PCB
2. Single-layer flexible PCB
3. Single-layer rigid-flex PCB
4. Single-layer high-frequency PCB
5. Single-layer aluminum-backed PCB

1 Single-layer rigid PCB

• Single-layer rigid PCB is a type that is made up of a rigid material such as fiberglass.
• These PCBs are hard and prevent the circuit from bending and breaking.
• It's used in applications i.e. calculators, power supplies etc.

A single-layer rigid is shown in the figure below.

2. Single-layer flexible PCBs

• A single-layer flexible PCB has a flexible substrate like polyimide in its manufacturing.
• Single-layer flexible has so many advantages over single-layer rigid PCBs. But the cost is too high for its fabrication. A single-layer flexible PCB is shown below.

A single-layer flexible PCB

3. Single-layer high-frequency PCBs

• Circuits emitting a frequency in Gigahertz, single-layer high-frequency PCB is used.
• Polyphenylene oxide (PPO) or Teflon Material is used in single-layer high-frequency PCBs.
• If you are selecting High-frequency single-layer PCB, you should consider many aspects such as dielectric loss, thermal expansion, water absorption, etc.
• A single-layer high-frequency PCB is shown in the below figure

A single layer of high-frequency PCBs

4. Single-layer rigid-flex PCBs

• Single-layer rigid-flex PCB is a combination of both Rigid PCB and Flexible PCB.
  
• Single-layer rigid-flex PCBs have so many advantages over single-layer rigid and flexible PCBs such as it reduces the size and weight of the overall PCB.
• Single-layer rigid-flex is shown below figure.

A single layer rigid flexes PCBs

5. Single-layer aluminum-backed PCBs

• Single-layer Aluminium-backed PCB has an aluminum substrate.
• Aluminum-backed PCB is used with the thermal insulating material for the heat to dissipate by Aluminium.
• Single-layer aluminum-backed PCBs are shown below in Figure.

A single layer aluminum backed PCBs

Steps for the manufacturing process of PCB

• There are a lot of processes involved in the construction of a PCB.
• Almost 12-20 machines are used in the manufacturing of a simple single-layer PCB depending upon the demand of the customer and the requirement of the product.
• For ease of understanding, single layer PCB manufacturing process can be defined as

1. Cutting & Cleaning of PCB sheet:

• The circuit pattern is drawn on PCB using the photolithography technique in which warm iron is used to draw a pattern from photo paper to PCB.
• Photo paper is removed by washing PCB having photo paper on it.
• After drawing the pattern, check connecting nodes, jumpers, and docking points for additional components.

2. Etching with ferric chloride:

• prepare a solution of ferric chloride with water in a 1:3 ratio and dip board into it.
• The processing speed in this step is affected by the temperature of the solution and the thickness of the foil. You have to moderately heat the solution to speed up the process.
• Again clean the board with alcohol.

3. Drilling holes on the single layer PCB:

• now holes are drilled according to the requirement of the product. Clean the board again.

4. Soldering holes and lubricate sides of the board:

• at this stage, first of all, holes are soldered to make them able to make connections between components and layers.
• After soldering holes lubricating the sides of the board with a cover layer is done.

5. Testing of the final board:

• at this stage, the final prepared board is tested for whether it is ready or not.

6. Packaging:

• in the end, the final packaging is done and now the single layer PCB is ready to be delivered.

Common mistakes in single layer PCB manufacturing:

Following mistakes are made by designers during the manufacturing 9f the single-layer PCB.

1. incorrect conducting paths width:

• The maximum allowable width of the conducting path should be drawn to avoid voltage loss, overheating of the conductor, and low mechanical strength.

2. improper power circuit designs:

• When the width of the track is not made maximum then problems like output ripples, output voltage loss, and interference have to be faced. To avoid these problems track width should be maximum.

3. grounding problems:

• To avoid grounding problems, a separate insulating layer is used for wiring.

4. small gaps between copper:

• Gaps between copper conductors deposited on the board should not be so small, this can lead to the violation of the integrity of the board.

5. large no of holes on one plate:

• By increasing no of holes, no of conductive paths increases, and this, in turn, increases resistance.

Application for single-layer PCB

It is no doubt that single-layer PCBs are very simple. But single layer PCBs are used still in such a lot of complex devices. Some devices are listed below.

1. Single-layer PCBs are used in digital cameras circuits.
2. Single-layer PCBs used in coffee-making machine circuits.
3. Single-layer PCBs are used in soiled state drives which are mostly used in the power industry.
4. Single-layer PCBs are utilized in switching relays which are mostly utilized in the automotive and power industry.
5. Single-layer PCB used in vending machine circuits.
6. Single-layer PCBs used in digital calculators which are consist of only a single PCB.
7. Single-layer PCB used in photocopy and printer machine circuits.
8. Single-layer PCB is used in radio and stereo equipment circuits.
9. Single-layer PCB is utilized in digital microwave timer circuits to modify on or off the oven timely.
10. Single-layer PCB is used in led lighting circuits for making power light circuits.
11. Single-layer PCB used in digital and analog power supplies circuits.
12. Single-layer PCB used in surveillance machine circuits.
13. Single-layer PCBs are used in sensors products circuits.
14. Single-layer PCBs are used in packing machines to achieve the high targets of fast-packing and are mostly used in packing industries.
15. Single-layer PCBs are used in timing circuits to switch on or off the machine timely.

Advantages of single-layer PCB

There are some advantages given below of single-layer PCB.

1. The single-layer PCs is very easy to design and has a lower probability to make incorrect design because the single-layer PCBs is very simple.
2. Its price is very less especially when it is ordered in bulk quantity as compared to the other types of PCBs.
3. It is easy to understand for anyone because it is a very simple circuit
4. Because its components are installed on only one side there for its a required lower jumper o compensate for the circuit.
5. Its drilling, soldering, de-soldering, and components inserting process is very easy because single layer PCBs only consist of a single layer.
6. Its design circuit required a very short time to make a simple design.
7. There is less probability of short-circuiting and producing noise because its components are installed at some distance from each other.
8. For fault tracing and repairing of this single layer PCB need less time.
9. When we compare the single-layer PCBs to the other types of PCBs. It is more reliable and efficient.
10. The installation of single-layer PCBs is very easy.

Disadvantages of single layer PCB:

• Single-layer PCBs have many advantages regarding cost, efficiency, and ease of installation but they still can not be used for any circuit because of their limitations. The limitations or disadvantages of using single layer PCB are discussed below:

The simplistic design and small space:

• Single-layer PCB has a very simple design and this simplistic design presents as the hurdle in complex devices that require a lot of components and connections.
• To mount a large no of components, large space is required but single layer PCBs don’t have enough space to mitigate this problem.

Slow speed and low operating capacity:

• As they have a limited no of components so their speed is slow, their power is also slow.
• Due to their low speed, they have low operating capacity.

Large size and high weight:

• To add components to the single-sided PCB you need to enhance PCB into its dimensions. As it is single-sided so that’s why we can not add layers. By enhancing PCB into its dimensions, the size of PCB.
• The enhanced size and large no of components ultimately enhance the weight of single-layer PCB.

Conclusion:

• At the end of it all, we can conclude that single-layer PCBs have unique advantages, benefits, and applications but as an end-user, you always have to choose which type of PCB you need.
• In modern technology advancements, single-layer PCBs are now in an underestimated situation but are still used.
• With a low budget and volumes of specific design single-layer PCB is the right choice when compared to the other types of PCB.

That’s all for today’s article. I hope you have enjoyed the article and made grip on the understanding points. However, if you still face any skepticism regarding single-layer PCB then please feel free to leave your questions in the comment section. I will provide an answer to these questions to the best of my knowledge and research skills. Also, provide us with your innovative feedbacks and suggestions you improve the quality of our work and provide you content according to your needs and expectations. Stay tuned! Thank you for reading this article.

A detailed Guide on PCB Fabrication Process

Hello friends, I hope you all are doing great. Today, I am going to share the 10th chapter in the PCB learning series. So far, we have studied the basics of PCB i.e. What is PCB? Main Types of PCB, techniques to mount components on PCB etc. Now, we are ready to have a look at the complete PCB Fabrication Process.

So, in today's tutorial, I am going to share a detailed guide on PCB Fabrication Process. We will discuss everything related to it i.e. How PCB boards are manufactured? Which material is used to fabricate printed circuit boards? etc. But before starting the Fabrication PRocess, we first have to understand a few terms/features. So, let's get started:

• PCB of DVD player:

RoHS-compliant PCB

• RoHS stands for Restriction of Hazardous Substances.
• EU ban the use of lead under the legislation RoHS. So, in PCBs, lead can't be used.
• RoHS-compliant PCB means that PCB is free from lead, Mercury and other heavy toxic metals.

PCB Lamination

• Laminates are prepared, first controlling pressure and temperature for cloth or paper with a thermoset resin and then a final integral piece of uniform thickness is formed.
• Its size can be up to 4×8 feet.
• Desired thickness can be achieved by controlling cloth weaves, thickness and resin percentage.
• Some important characteristics of the laminate are:

1. strength of fire retardant
2. dielectric constant(e) of the laminate
3. the loss factor of laminate
4. tensile and shear strength of the laminate
5. the glass transmission temperature and
6. the z-axis expansion coefficient.

Different dielectrics are used to obtain different insulating values depending on the requirement, which are:

1. Polytetrafluoroethylene(Teflon)
2. FR-1, FR-2, FR-3, FR-4, FR-5,and FR-6
3. CEM-1, CEM-2, CEM-3, CEM-4, andCEM-5.

Here are a few of the factors affecting the laminate quality: 

1. Size of the board.
2. Increasing frequencies.
3. Uneven distribution of fiberglass glass or other filler.
4. Bubbles and thickness variation in resin.
5. Variations in the dielectric constant.

Key Substrate parameters

• The circuit board substrates are made up of dielectric composite materials.
• The composites contain

1. matrix(epoxy resin)
2. reinforcement(glass fibers, paper etc.)
3. filler (ceramics)

Reinforcement has two major classes of materials

1. woven: these are cheaper but have a high dielectric constant that is not suitable for many applications.
   
2. non-woven: these are expensive but suitable for RF and analog applications.

Key parameters of substrates are:

1. thermomechanical(tensile and shear strength, glass transition temperature and thermal expansion)
2. electrical(tracking resistance, dielectric constant, dielectric strength, breakdown voltage etc.)
3. others(moisture absorption)

• At a transition temperature, thermal expansion increases because the resin in the composite becomes soft. Below transition temperature, thermal expansion decreases and matches with copper and glass. Above transition temperature, a very high thermal expansion exerts mechanical overload on the board components.
• Expositions to high temperatures and repeated soldering can be the reason for the failure of the plating, especially with thick boards.
• Dielectric substrate constant depends upon the material used and the frequency(decreases with the increase in frequency). Signal propagation speed depends upon dielectric and phase distortion depends upon frequency. So flat dielectric constant vs characteristics frequency is important. The transmission line impedance is inversely proportional to the frequency therefore faster edges of signals reflect more than the lower edges of the signal.
• At maximum voltage gradient, material suffers from breakdown is determined through dielectric breakdown voltage.
• Tracking resistance means how the material resists high-voltage electrical discharges creeping over the surface of the board.
• The amount of electromagnetic energy from the signals in the conductor, that is absorbed in the board material is called loss tangent. It is important for high frequencies. The cost of the board increases by choosing low-loss material(expensive) in high-frequency digital design.
• When the material is exposed to high humidity or water, moisture absorption occurs. Both resin and reinforcement absorb water. Absorbed water can cause degradation of key parameters. It affects tracking resistance, dielectric parameters and dielectric constant. Absorbed water can cause cracks during heating and soldering.

Common Substrates

• FR-2, FR-4, aluminum or insulated metal substrate( IMS) and flexible substrates(Kapton and parallax) are the commonly used materials as the substrate.
• FR-1, FR-3, FR-5, FR-6, G-10, G-11, CEM-1, CEM-2, CEM-3, CEM-4, CEM-5, PTFE(Teflon), RF-35, alumina and polyimide are rarely used as a substrate.

Copper thickness

• Copper thickness is the weight of copper per area. Its unit is ounce/square foot. (1 ounce/ square foot = 34 micrometers thickness).
• A heavy copper layer means 3 ounces of copper per foot. It is used for high currents and to dissipate heat.
• In FR-4 substrate 1oz copper/feet is the common thickness. Other options are also available.
• Metal core boards use thicker copper(35 micrometers) for high-power devices.

PCB Circuit properties

• Trace is made up of a flat but narrow copper foil and its resistance should be low. Its resistance is determined by its length, width, and thickness.
• In multilayer PCB, one layer is made up of solid copper that is used for power and shielding return.
• In microwave circuits, to attain consistent impedance stripping or microstrips of transmission lines are used.
• HDI PCBs have vias or tracks with a diameter of under 152 × 10^6 m.

Safety measurements

Some safety measurements should be considered, i.e.

1. flammability
2. electrical tracking
3. maximum operating temperature
4. heat deflection

Old Technique for PCB Manufacturing

In the beginning, PCBs are designed on a clear mylar sheet having a photomask.

• First, component pins/pads are laid out on the mylar and then traces are routed to connect with the pads.
• Self-adhesive tape is used to make traces.
• In mylar layout, pre-printed non-reproducing grids are used.
• The final photomask is produced onto blank copper-clad boards having photoresist coating using a photolithographic technique.

Modern PCBs are produced by adopting the following steps.

PCB Fabrication Process

PCB manufacturing consists of many complex steps.

1. PCB Computer-aided Design(CAD):

• CAD software are used to create the software image of the PCB design.
• Commonly used PCB design software are Eagle, Altium Designer, OrCAD, KiCAD, Proteus etc.
• Online CAD software are also available i.e. EasyEDA.
• Once the design is finalized, the CAD software generates the Gerber files, which include detailed information about drill drawings, copper tracking layers, component notations apertures, components labeling etc.
  

2 Panelization:

• Panelization is the process of adding a PCB design multiple times in a single PCB board.
• If you want mass production, the best practice is to create a panel of your PCB design.
• It reduces the cost and manufacturing time. (We will cover PCB panelization in our next chapter)
  

3 Copper Pattern Printing

• On the copper foil layer, the PCB design generated from CAD software is printed using black ink, it acts as a protective mask for the copper under design traces/pads.
  
• The remaining unwanted copper has no black ink and a process called etching removes it, as it's unprotected by the design mask.
• Some other techniques used to create copper patterns:
  

1. Silkscreen printing
2. Photoengraving
3. PCB milling
4. Laser resist ablation
5. Laser etching

4 Chemical etching:

• The process of submerging the board into the ferric chloride solution is called chemical etching.
• The function of etching is to remove copper from all the surfaces not protected by the resist.

5 Lamination:

• Note the via, visible as a bright copper-colored band running between the top and bottom layers of the board.

[TEPImg9]

• A stack of material is laminated in a press by applying heat and pressure for a certain time. Multi-layer PCBs have trace layers inside the board.

6 Drilling:

• Drill bits are used to drill holes through PCB. It is made up of solid-coated tungsten carbide.
• Holes can be made conductive by electroplating. These conductive holes are used to electrically connect the layers of PCBs.

7 plating and coating:

• PCBs are plated with solder, tin or gold over nickel.

8 Solder Resist

• Areas that do not need to be soldered are covered with solder resistance.

9 legend printing:

• After the solder resists is done, a legend is printed on both sides of the PCB.
• Silkscreen printing, liquid photo imaging, and inkjet printing are the three methods to print legends on PCB.

10 Bare board test:

• Boards without components are tested for shorts and open. It is called the bare board test.

11 Assembly:

• Assembly is the process of stuffing bare boards with electrical components.
• After assembling, many tests are performed on the PCB. If it fails any test, means it needs rework.

12 Protection and Package

• For protection, a conformal coating is done to avoid leakage of current and corrosion.
• After all the protection checks, the final product is placed in a package.

Precautions

1. Based on the required circuit, the PCB board dimensions are decided.
2. Components and heat sinks are also positioned carefully.
3. Decide the no of layers, ground and power planes as a power plane acts to encounter a ground plane, so shouldn't be together.
4. Signal planes should be on external layers, especially if both AC and DC involve in the circuitry.
5. High-frequency signals are routed in the internal layers between ground & power planes for attaining optimal EMI performance.
6. Routes copper thickness, dielectric layer thickness and trace width are used to determine the line impedance. To route signals, normally three striplines are used named: microstrip, stripline and dual stripline.
7. During components and vias placing on the PCB board, heat effects and geometry should be taken into account.
8. If you are placing an order on a PCB manufacturing company, make sure you provide the final Gerber files.
   

How to order for PCB Manufacturing?

There are many online PCB Fabrication Houses available, offering PCB & PCBA manufacturing services. We are going to take the example of JLCPCB Fabrication House. Let's see How to place an online PCB Fabrication order on JLCPCB company.

• First of all, open the official website of JLCPCB Fabrication House.
• They have placed an online Quote Calculator, where you need to enter all your PCB requirements and it will give you the cost and time required to design it.

• As you can see in the above figure, I have placed an order of 5 PCBs and the size of each PCB is 100x100mm, and I am getting a price of $2.
• As you increase the quantity of PCB boards, the price per board reduces.
• JLCPCB is a well-renowned PCB Manufacturing House and always provides quality work at a nominal price.

APPLICATIONS OF PCB:

• In electronics: used in computers, home appliances, communication systems etc.
• In industry: used in power, measuring and industrial equipment.
• In medical: used in scanning, monitoring and surgery equipment.
• In the automotive industry: used in navigation, media devices, control systems and proximity monitors.

ADVANTAGES OF PCBs:

• Inexpensive/ cheaper.
• High volume production.
• Hold the components easily.
• Highly reliable.
• Automated soldering is possible.

So, that was all for today. In the next lecture, we will have a look at the PCB Panelization Process. I hope you have enjoyed today's lecture. Thanks for reading.

Introduction to Double Layer PCB

Hello! Friends I hope you are all fine. In today's article, we tend to unlock the details on the double sides of PCB which is a type of PCB. It comes with a conductive copper layer on both sides of the board, unlike single layer PCB which has only layer one side of the board. I will try to elaborate on each and everything about double-sided PCB with the best of my effort. So you do not need to move your attention to another source for elaborating this article. In this article, we illustrate the double-layer PCBs, their advantages and disadvantages. We will also study double-layer construction methodology, its applications. In termination, we will discuss the conclusion of today’s article. Let’s start our article by exploring PCB and its main applications. Let’s start to absorb the basic and advanced information about double layer PCB.

Before discussing the double layer PCB. we must have an idea about what’s PCB.

PCB and its classification

 PCB is an abbreviation of printed circuit boards. PCB may be a sleeky chip created by compound epoxy glass fiber or laminated completely different substances. It includes a plate of insulated substantial and a sheet of copper foils coated to the substrate.

Criteria of Classification of PCB

PCBs are classified according to their number of layers and holes on them.  There are three types of PCB depending on the number of their layers.

• Single-layer PCB
• Double-layer PCB
• Multilayer PCB

Now to move our attention back to our article which is double layer PCB

Introduction to double-layer PCB

A double-sided PCB is also known as a Two-layer PCB is a kind of PCB that has a copper layer on both sides aboard. Here copper layers means the conductive layers. Simply we can say that it Comes with two conductive patterns on two sides of the base material which is called the substrate. The pattern on the sides is connected using a connection bridge which is known as VIA.

2-Layer PCB Pricing

• Let's have a look at the pricing of 2 Layer PCB, so I am going to take the example of PCBWay Fabrication House.
• If you have a look at the below figure, you can see that, if we place an order of:
  • Size: 150x100mm
  • Quantity: 10
  • Layer: 2
• It will cost us $41 in total, and it's quite affordable.
• The price per PCB board decreases as you increase the quantity.

What is via?

 Via is a hole in the vertical direction on the PCB board which is filled with metal foils due to which we connect the writing patterns.

• The area of double-sided PCB is twice that of single-layer PCB that allowing it to be used in vast applications with high-density components

Purpose of double-sided PCB 

• The main purpose of this board over single layer PCB is that on this board we can connect components on one side with the other due to the presence of the hole on it. We can easily tackle with connections on this board although it is no easy task to develop a double layer PCB.

Types of double-layer PCB 

 There are two types of double-layer PCB.

• Without through-hole metallization (non-PTH)
• With through-hole metallization ( PTH)

PCB Manufacturing Process

 Following steps are included in making a PCB:

1. Initialization
2. Optical lithographic
3. Etching
4. Stripping
5. Plating of tin
6. Drilling
7. Testing
8. Component loading
9. Soldering

Initialization

• First of all, we must have a print of layout which may be obtained from Computer-aided machine, then cut the copper layer according to requirements and make sure that board is clean and free from any dust than mounting holes on it.

Optical lithographic

• In this step, we may transfer the copper tracks by exposing them to radiation sources like UV radiations

Etching

• This is used to remove the copper-clad which is unnecessary.  For this purpose the board is  dipped in the etching solution  and remains in solution for 6 to 7 minutes at 40° C . There are  many types of etching solutions like

1. Ferric chloride
2. Cupric chloride
3. Alkaline ammonia

Stripping and tin plating

•  In this step final touch is given to the copper layer on board and plating is optional which protects the copper from being oxidizing.

Drilling and testing

•  In this step, components are created on board of different widths. This may be done by using manually operating drill machines by using CNC drilling machines.

Techniques for interconnecting components onboard

Technically two methods are used for this task.

• Through-hole technology
• Surface-mounted technique

Through-hole technology

• It is a technique in which we can make an electric circuit by using a wire which passed through holes and bored into PCB. In the late 1980s, every component was pointed through this technique on PCB.

 Surface-mounted technology 

• In this technique, there is no separate use of Wire. In its place, we can join components straight to chips which reduces space requirements.

Construction of double-layer PCB 

• The construction of this board is alike to single-layer PCB, its construction is delineated here with elaborate.
• In this circuit substrate is factory-made by the fiber or epoxy resins, the sort of base material depends on rigidity and adaptability of aboard.
• In the double layer PCB, PCB over base substances copper lamination is done to supply a semi-conductive method for parts.
• To protect From setting each side of the Board contains a solder mask over copper covering.
• There exists a silkscreen on top of the sides whose purpose is to able a person to add symbols and character on board so that a standard person will perceive the Board function.
• Double-sided PCB area units are terribly like single-sided PCB except that they need two-sided traces with high and bottom layers. These boards will mount conductive copper on either side of the card that permits the trace to cross over one another. This leads to the next density of circuit while not the Requirements of point to point fastening. These kinds of circuit boards area units are a lot of advanced than single-sided PCBs that are often harder to supply. However, the advantage of victimization double-sided PCB so much outweighs the con’s

Double-sided circuit boards are one of the foremost well-liked kinds of PCBs. They allow makers to supply a lot of advanced circuits which may have profit uses in higher technology applications.

Advantages of double-layer PCB over single layer PCB 

• The most important point is that number of interconnection are approximately double that of single-sided PCBs
• They are more flexible and have easier electrical interconnections.
• Single-layer PCB has only one conducting layer over base material while double layer PCB has two conductive layers on both sides of base material known as a substrate which is made of fiberglass and is compact in its sense.
• Both double layer PCB and single layer PCB  works as an electronic catalyst to deliver power to other components
• Double-sided PCB tends to increase the circuit density and reduce the overall cost.
• Although double-sided PCBs have complex circuits as compared to single-sided PCBs they are perfect and more suitable for advanced electronics because they can be used on both sides which reduces the side of the board in return reduces the overall cost.•The most important advantage of double-sided PCB is that we can repair and rework their connections.

Disadvantages of double-layer PCB 

• We need very careful attention for manufacturing of layout of double-sided PCBs especially in the distribution of power across the different components.
• As they have the open structure of circuit loop there may be a chance of EMI radiations which may change the crosstalk between closely spaced tracks overboard

Application of double-layer PCB 

• Due to the availability of flexibility in their structure, Double-sided PCBs are used in many applications for various purposes.
• High low temperature and solder coating are one of few important applications of Double-layer PCB.
• Double-sided PCBs are used in merchandising machines, amplifiers, automotive dashboards, and plenty of lots.
• Double-layer PCBs are used in the red lightning circuit which makes the light circuit.
• Double-layer PCBs are used in printers.
• Double-sided PCBs are used in Industrial controls for various purposes.
• Double-sided PCBs are used for instrumentation.
• Double-sided PCBs are used for testing the types of equipment.
• Double-sided PCBs are used in power supplies and hard drives.
• Double-layer PCBs are used in converters.
• Double-layer PCBs are used for control relay purposes.
• Double-layer PCBs are used in the Automotive dashboard for controlling the different functions.
• Double-sided PCBs are used in traffic systems
• Double-sided PCB has wide use in vending machines.
• Double-layer PCBs are used in inline reactors.

Conclusion

In the end, we concluded that double-layer PCBs have two layers than a single layer which has one layer. Due to advanced technology requirements, we need double-layer PCBs. Double layer PCBs are less costly but they have innovative features than single layer PCBs. This worthy feature is the demand of the modern era. Double layer PCBs have worthy applications. It also has some drawbacks which demanded that we have to develop PCBs that are effective than double-layer PCBs. You always need to opt for which kind of PCBs you would need.

That’s all for today’s article. I hope you've got enjoyed the article and built a grip on the understanding points. However, if you continue to face any skepticism concerning double-sided PCB then please be at liberty to depart your queries within the comment section. I'll give a solution to those inquiries to the simplest of my data and researching skills. Also, give North American country along with your innovative feedbacks and suggestions you improve the standard of our work and supply you content in keeping with your wants and expectations. keep tuned! thanks for reading this text.

 

Quick-Turn PCB Prototyping Service

Hi friends, I hope you are enjoying yourself a lot and having a great deal of fun. Our mission is to help you by providing quality content that meets your expectations so now today we will discuss all quick turn PCB prototyping services. We will discuss what is quick-turn PCB? What is a PCB prototype? What is a quick-turn PCB prototyping service? Quick turn PCB general Capabilities provided by companies. Benefits, applications and importance of quick turn prototyping service. Online Quick-turn PCB service providers and time measurements. So, let's get started:

Overview

• First of all, before starting the discussion we have to know about the meanings of the words used in our topic heading.
• We have to make grip on the meanings of quick turn, PCB, prototype, and service. After understanding the heading of the topic we will be able to understand core concepts.
• Quick turn: quick turn means something or someone that does things with great speed. Day traders use the quick turn technique to make a great deal of profit.
• PCB: PCB stands for the printed circuit board. It is a combination of conductive and insulating layers to perform specific functions that meet the demands of customers.

• The prototype is defined as an original model on which something is patterned. It is an early sample product built to test a process or concept.
• Now prototyping is a fundamental process for designing a new product on which electrical components will be patterned.

• Service: service is a system that is used to provide utilities like providing PCBs to the provided/desired location.

What is a quick turn PCB?

• Now after understanding the meaning of each term used in the heading we have to understand what is quick turn PCB? What is PCB prototyping and then we will discuss what is quick turn PCB prototyping service?

• A quick turn PCB means that a customer has their PCB faster than ever before.
• A quick turn ensures that a customer doesn’t have to wait for their product so it reduces delays.
• A quick turn also ensures that the manufacturing time for the PCB is reduced.

What is PCB prototyping?

• A PCB prototyping is to help designers to determine if there are any faults in the original PCB.

• It helps to improve performance and enhance efficiency.
• As prototypes are crucial so it is very difficult to make changes in the PCB which is manufactured.
• Quick turn PCB prototyping service means that providing PCB prototypes to the customers at a very fast speed, without delay.

Online Quick turn PCB prototyping service providers:

There are some online quick turn PCB prototyping service providers available. The one I am going to recommend is JLCPCB Fabrication House. JLCPCB provides this service of Quick-Turn PCB Prototyping for researchers so that they could test their projects in no time. Here are a few of the key points of this service provided by JLCPCB:

• They provide 1-50 layer PCBs with PCB Order Quality < 1m2 within 24 hours, while normally it takes 2-3 days for accomplishing such tasks.
• For PCBs with order quality between 1m2-5m2, JLCPCB takes around 3-4 days, while the normal time range is 5-7 days.

Few other Quick-Turn PCB suppliers are:

1. pcb4u.com

Location: Santa Clara

2. pcbway

Location: china Capabilities: preferred for minimum trace and hole size...etc.

3. aipcba

Capabilities: PCB fabrication, SMT services, PCB assembly services.

4. pcbunlimited

Location: US-based Capabilities: US prototype PCBs, PCBs panel share, offshore PCBs, PCB   design and layout services, PCB assembly services.

5. pcbgogo

Capabilities: FIXME(minimum trace and hole size...etc) 6. Other Quick turn PCB prototyping service providers are:

• Homebrew fabrication
• Breadboard killer
• Foundation technology
• Linksprite
• Kingfield electronics- CEM services
• Apex
• Cadsoft Eagle
• Exception group
• Bittele electronics
• Technotronic
• 4pcbassembly
• Sinomicro PCB
• Asian circuits
• Standard printed circuit board limited
• PCB train
• Euro circuit.....etc

PCB Capabilities - Quick-turn PCB

• Providing PCB prototypes within 24-72 hours is the quick turn PCB prototyping service.
• Companies do not have to look eye only at providing PCB at a fast rate but they don’t have to compromise on the quality of the product.

Items	General Manufacturing Capabilities	Companies general Remarks
How many layers	1-10 layers	For orders above 10 layers, contact to company.
Material	Aluminium or RF-4	For Flex, Rigid-flex, Metal-based (Aluminium etc.,), HDI, Halogen-free, High Tg, etc.
Maximum dimensions of PCB	500*1100mm (min 5*6mm)	For any size Greater than these Standard dimensions customers have to contact to the company
Tolerance in board size	±0.2mm/±0.5mm	±0.2mm for CNC routing, and ±0.5mm for V-scoring.
Thickness of the board	0.2-2.4mm	0.2,0.4, 0.6, 0.8, 1.0, 1.2, 1.6, 2.0, 2.4mm. For other thicknesses, customers have to contact to company.
Tolerance in the thickness of board	±10%	Normally “+ Tolerance” will occur due to PCB processing steps such as solder mask, electroless copper and other types of finish on the surface.
Board Thickness Tolerance(t<1.0mm)	±0.1mm
Minimum manufactural Trace	0.1mm	Min manufactural trace is (0.1mm), To save cost design trace should be above 6mil(0.15mm)
Min Spacing		Min manufactural spacing is 0.1 mm. To save cost it should be 6mil(0.15mm)
Thickness of outer copper layer	1oz/2oz/3oz(35µm/70µm/105µm)	Also known as copper weight. 35µm=1oz, 70µm=2oz, 105µm=3oz. For copper weight greater than 3oz customers have to contact the company.
Thickness of inner copper layer	1oz/1.5oz(35µm/50µm)	Inner copper weight as per customer’s request for 4 and 6 layers is 1-1.5 oz.
Drill Sizes	0.2-6.3mm	Min hole size is 0.2mm, max drill size is 6.3mm. Any holes greater than 6.3mm or smaller than 0.3mm customer will have to pay extra charges.
Annular Ring’s minimum width	0.15mm(6mil)	Min width for Annular Ring is 0.15mm(6mil), for pads with vias in the middle
Diameter of finished hole	0.2mm-6.2mm	The final hole diameter will be smaller than the size of the drill because of copper plating in the holes.
Tolerance of finished hole size	±0.08mm	For example, if the drill size is 0.8mm, the finished hole diameter ranges from 0.72mm to 0.88mm will be considered acceptable.
Solder Mask	LPI	Liquid Photo-Image able is the most adopted. Thermosetting Ink is used in the inexpensive PCBs
Width of minimum character	0.15mm	Characters of less than 0.15mm wide will not be Identify easily.
Height of minimum character	0.8mm	Characters of less than 0.8mm high will be too small to be identified.
Width to Height Ratio of character	1:5	In PCB silkscreen legends processing, 1:5 is the most suitable ratio for character width to height.
minimum diameter of PHH( plated half holes)	0.6mm	Design Half-Holes greater than 0.6mm for better connections.
Surface Finishing	HASL with lead HASL lead free Immersion gold	These are the tree most popular types of surface finish.
Solder Mask	Black, yellow, white, blue, green, red	No extra charge (Green, Red, Yellow, Blue)
Silkscreen	White, Black and None	No extra charge.
Panelization	Tab-routing with Perforation (Stamp Holes)V- scoring Tab-routing	For break-routing min clearance between boards should be 1.6mm and for V- scoring it should be zero.
Others	UL certificate, Fly Probe and A.O.I. testing, ISO 9001:2008	No extra charge.

Quick turn PCB service types:

PCB manufacturing service providers provide PCB quick turn services as

• 1-day quick turn PCB prototype
• 2 days quick turn PCB prototype
• 3 days quick turn PCB prototype
• 5 days quick turn PCB prototype
• 10 days PCB standard PCB prototype
• > 10 days PCB prototype.

Benefits of quick turn PCB prototyping service:

• Why do designers rely on prototypes instead of making a standard product? The answer to this question is that the prototype allows designers to test the functionality of the product in the design process at several stages and allow them to make adjustments according to their needs.
• Prototyping creates several advantages for customers and manufacturers as

1. Reduced timeline:

PCB prototypes help designers to complete their final product in these ways by saving their time.

• PCB prototypes complete the testing process at a fast rate. Without prototypes, flaws will waste a lot of time, lost revenue, and make a customer unhappy.
• PCB prototypes also save time by providing visual assistance to clients during the production process.
• At several stages, Prototypes help in testing before a full production run and save not only time but also minimized rework.

2. Reduced costs:

Prototypes help in reducing cost by avoiding the following issues:

• Catching design flaws
• Pinpointing cost-saving adjustments.
• Determining product adjustments.

3. Test components individually:

Designers use PCB prototypes for testing purposes. Most beneficial testing is achieved by testing simple PCBs. This type of testing is used to achieve the purposes listed below

• Testing design theories
• Breaking down complex designs.

4. Accurate reliable prototype:

Accurately designed reliable prototypes help throughout the designing and manufacturing process. Quality PCB prototypes allow designers to test the following aspects:

• PCB design
• Functional testing
• Conditional testing
• Final product design

5. Manufacturing review and assistance:

Using third party PCB prototyping services companies gain benefits but several things can go wrong in the design process that results in mistakes listed below:

• Excessive input
• Design blind spots
• Design rule check

Applications of quick turn PCB prototype:

Quick turn PCB has several applications in different industries. The applications in different scenarios are listed below:

1. Electronic designers who require high-quality boards use quick-turn PCB prototypes.

2. PCB assembly manufacturers designs products for the mass market use quick turn PCB prototypes to fulfil the needs of the market. 3. Designers also need to work on new ideas so they use quick turn PCB prototypes. 4. To provide the investors and clients the samples of their products designers need to show quick turn PCB prototypes.

Importance of quick turn PCB prototyping service:

• The role of PCBs in the best performance of electronic devices can not be denied.
• Electronic devises based companies heavily depend upon PCB prototyping firms and their efficiency of fabrication.
• However, to meet challenging deadlines, pressing schedules, and excellent quality PCB manufacturing, quick turn PCB prototyping service plays a crucial role.
• Let’s know-how companies benefit from their quick services and attain their business goals.

1. By providing quick turn services, companies increase their number of customers.
2. For the projects that need to be completed in a very short time, companies charge extra amounts. To attain the goals of extra profit, and everything related to PCB manufacturing should be perfect.
3. By providing reference prototyping services, companies built a trust relationship with their customers.

• Listed above are the benefits/ importance for companies providing quick turn PCB prototyping service. Quick turn PCB prototyping service is not only beneficial for companies but also for clients. Here is the importance of quick turn PCB service for customers.

1. By obtaining their prototype according to their demands, customers can complete their projects on time.
2. Customers do not have to waste their time in transportation and searching for PCB, they just have to order PCB and mention their requirements. Their desired PCB will be at their door.
3. There are also some cost benefits to customers in this service.

Quick turn PCB prototyping service time measurement:

• When an order is placed in the morning like at 9:00 am then at next business day noon, 1 day is completed and from noon after 24 hours, 2nd day is completed from your order.
• If an order is placed at 12:00 am then after 24 hours, 1 day will be completed. And next days will be counted similarly.
• For orders placed after 4:00 pm lost much of their time so placing late time orders is not suitable.

Conclusion:

When we think about PCB prototyping, it seems an additional step that will enhance the PCB cost and we consider it one that never is overlooked. But the reality is that it is best to weed out errors, flaws, and faults before proceeding to the final product. Prototyping helps in reducing cost, provides us with quicker turnaround time, and provides you with more efficient design. Now designers always prefer prototypes before developing new innovative ideas as well. They know about the value of time, cost and quality so suggest to students, engineers, and innovators to use prototypes. In the end, we can say that the value of PCB prototypes can not be neglected, they are as fruitful and helpful as standard PCBs.

That’s all for today’s article. I hope you have enjoyed the article and make grip on the understanding points. However, if you still face any skepticism regarding single-layer PCB then please feel free to leave your questions in the comment section. I will provide an answer to these questions to the best of my knowledge and researching skills. Also, provide us with your innovative feedbacks and suggestions you improve the quality of our work and provide you content according to your needs and expectations. Stay tuned! Thank you for reading this article.

PCBA: Definition, Types, Material, Manufacturing Process, Price & Applications

Hey Guys! Hope you’re well. I welcome you on board. In this post today, I’ll walk you through PCBA (Printed Circuit Board Assembly) in detail. It's our 4th tutorial in the PCB learning series.

In the 1st tutorial, we studied printed circuit board(PCB) in detail and learned that PCB provides physical support and electrical connection through conductive copper layers for the electronic components placed on the board. We have seen in our previous tutorials that when we place our PCB order on some PCB fabrication house, they provide us with a PCB board without electronic components. We have to solder the electronic components on the board. But now these PCB companies also offer a service to provide finished PCB boards with electronic components attached. Such a finished PCB board with electronic components is called PCB Assembly(PCBA).

You can place these components by yourself, if you know how to solder them on the board or you can outsource it to the PCB company for the smooth insertion of these components on the boards without compromising the quality of the PCB. Curious to know more about PCBA? Keep reading.

PCBA Definition

• PCBA(Printed Circuit Board Assembly) is a complete PCB board, where electronic components are mounted by the PCB company.
• Several steps are involved in the Printed Circuit Board Assembly manufacturing process.
• Each step must be in harmony with the next one to ensure a seamless production process for getting a quality final product.
• A PCBA normally passes through a reflow furnace heating to develop a mechanical connection between the components and the PCB.

Let's have a look at the Manufacturing process of PCBA in detail:

PCBA Manufacturing Process

The PCB undergoes DFM(design for manufacturability) check before the actual PCBA process even starts. The DFM check cross-checks the final PCB structure with the initial blueprint of the design. This check identifies any missing links or potentially redundant and problematic features in the final PCB design.

[TEPImg6]

If PCB doesn’t undergo this check, the PCBA process can create trouble in properly mounting the components on the board and maintaining a flawless electrical connection between them. DFM checks not only reduce the cost of the manufacturing process but also ensure the overall functionality of the PCB.

PCBA production process comes with the following steps.

1. Solder Paste

Before adding components on the board, a solder paste is added to the areas, where components rest on the finished PCB. The solder paste comes with greyish tiny balls of metals and is mixed with the flux that turns to a chemical composition and should be added in the right amount & in the right areas of the board.

To add the solder paste, a mechanical fixture is used to hold both the PCB and solder stencil in place. An applicator then takes the solder paste in precise amounts and places it on the desired PCB areas. The machine rolls the solder paste evenly on the intended PCB areas. As the stencil is removed, the solder paste sits on the desired areas.

2. SMT Assembly

After properly adding the solder paste on the board, the board is then passed through the pick and place process, where the robotic machine is used to pick the surface mount components from the reels and place them on the intended areas of the board.

The components added remain in the desired areas due to the sticky feature of the solder paste. The solder paste comes with enough bond strength that keeps the components in place.

Earlier this procedure was practiced manually by humans. However, the inception of advanced technology removed the need for this erratic manual process, since the automated process by machines is more accurate and efficient than the traditional manual process.

3. Reflow Soldering

Once the electronic components have been placed in the desired locations, they remain there due to the presence of solder paste. The board then undergoes a Reflow Soldering process that solidifies the solder paste to keep the components at the required positions.

In this process, the finished board is transferred to a conveyor belt that passes through a big reflow oven having a series of heaters; the temperature of these heaters stays around 250^oC which generates gradual heat to bake the board. At this stage, the temperature is high enough to make the solder melt, keeping the components tightly in place.

Once the solder has been melted down, the finished product is then passed through a series of cooler heaters that cools down the melted solder paste, giving it strength and creating a permanent solder joint to firmly connect the surface mount components with the board.

This is the reflow soldering for the one-sided PCB. Know that for two-sided PCB the stenciling and reflowing will be done separately for each side.

4. Inspection

Once the reflow soldering has been done, the assembled board undergoes a proper inspection where the functionality of the board is tested. As the PCB passes through a reflow soldering process, it may result in poor connection quality or in worst cases, the elimination of the entire connection. To check these problematic features and common errors, the assembled board undergoes a careful inspection.

• Optical Inspection: Recognize that, manual inspection is not an option for inspecting hundreds of surface mount components on the boards, instead, automatic optical inspection is exercised to look for the defects and errors in the board. In optical inspection, an automatic optical machine is used that comes with high-powered cameras that are located at different angles to monitor the connections. The solder connections reflect light at high speed with different intensities, allowing the machine to analyze the connections of lower quality.
• X-Ray Inspection: For complex and layered circuit boards, the X-ray inspection method comes into play, where X-rays are used for the inspection. With X-rays, layers become transparent, helping you see through the layers and identify the common problems on the board. These inspections are carried out before the final functional test inspection which involves the steps to make sure the board is fully functional and does the job perfectly.

5. Plated Through Hole Components

Based on the type of PCB board and the components used, the PCB assembly may go beyond the scope of SMT components insertion. In that case, Plated Through Hole(PTH) components insertion is used, where holes are drilled on the board and go completely through the board establishing a conductive path from one side of the board to another. Solder paste is not used in this case because it won’t stick and creeps into the drilled holes. In this PTH process, two types of soldering processes may be used:

• Manual Soldering: This soldering is manually done by humans. In this process, one person at the station is given the task to insert components in the desired PTH area. Once finished, the board is transferred through a conveyer belt to another station where another person is destined to insert another component. The cycle continues until each hole is filled with the desired component.
• Wave Soldering: Wave soldering is an automatic process. Once the PTH components are placed on the desired hole areas, the board is transferred through a conveyer belt that passes through a special oven that smears the layer of melted solder on the bottom of the board, soldering all pins at once.

6. Functional Test

In this process, the finished product undergoes the final inspection called the ‘functional test’ where simulated power signals run through the PCB to analyze the electrical characteristics of the board.  If voltage, current or signal output in these characteristics show sudden fluctuation beyond the permitted range, it means the board has failed the test.

7. Feedback

It is important to investigate any failures to guarantee the functionality of the manufacturing process. The recommended place to monitor the output and the potential errors is the optical inspection stage because errors are detected and rectified at this stage. This saves time ^ & money and avoids PCB production with similar defects.

Where to place PCB Assembly order?

• JLCPCB is an excellent PCB fabrication house that also provides PCBA services.
• From solder paste printing and SMT to reflow soldering and optical inspection, the board goes through every step with careful scrutiny, ensuring top-quality finished PCB assembly with electronic components.
• If you’re looking for reliable and economical PCBA service, you should give JLCPCB Fabrication House a try, you won't regret it.
  

PCBA Pricing Factors

• The price of PCBA is obviously more than the manufacturing of a simple PCB board. In PCBA, electronic components are mounted on the PCB using SMT technology.
• The size of the circuit board and the number of components that need to be mounted on the board plays a key role in defining the overall cost of the assembled circuit boards.
• Moreover, the total number of holes and their sizes are also important factors while defining the price of the board.
• Similarly adding more layers to the board and the type of material used will influence the cost.
• The customization in the manufacturing process will affect the cost; the more custom features you would like to add to the board, the more the cost.

PCBA Applications

PCBs are the backbone of electronic devices used for commercial and domestic purposes. More often big electronic companies don’t spend time in designing the PCB and then separately mounting the electrical components on the circuit boards. They purchase PCBA services, where circuit boards come ready-made installed with the components.

The common PCBA applications include:

• Companies prefer PCBA services for making consumer electronics, calculators, and smart toys.
• PCBA services come in handy in the manufacturing of auto parts.
• Automotive companies buy PCBA services to install circuit board assemblies in the antilock brake system, airbag control, audio-video system, engine timing system, ignition system, and more.
• The circuit board assemblies are used in heart-related applications live developing the pacemakers and heart monitoring devices.
• Military and defense systems prefer PCBA services for making the defense system, aerospace, naval, and aviation applications.

That’s all for today. So far, we have discussed the basics of both PCB and PCBA, now we will have a look at the Top PCB Manufacturers to place your order. Hope you’ve enjoyed reading this article. If you have any questions, you can pop your comments in the section below. I’d love to help you the best way I can. Thank you for reading the article.

Top Printed Circuit Board Manufacturers Online

Hi Guys! I welcome you on board. Happy to see you around. In this post today, I’ll walk you through Top Printed Circuit Board Manufacturers Online. It's our 5th tutorial in the PCB learning series.

Whether you’re a hobbyist working on your electronic project or someone who wants to develop an electronic product, PCB is an integral part of creating electronic units. With scores of PCB manufacturers available online, it’s very challenging to pick one that absolutely resonates with your needs and requirements. So how do you keep up when almost every company claims to be the best on board?

We’ve picked the top printed circuit board manufacturers online that you can select for developing your electronic projects.

Let’s get started.

Top Printed Circuit Board Manufacturers Online

The top printed circuit board manufacturers include:

1. JLCPCB

JLCPCB tops the list for several good reasons. Introduced in 2006, JLCPCB comes with advanced PCB technology that ensures both academic and compact products with fully automated production lines. They offer an easy-to-use online system to order PCB; you just need to fill up your requirements on the online form and upload the Gerber file, and you’ll get a quick quote based on your needs.

Whether you need a single PCB for your project or you want orders in volumes, JLCPCB is a one-stop shop for providing PCB prototype and SMT assembly services. More often, you’ll get PCB delivered to your doorstep within 3-5 business days, however, it also depends on the nature of the PCB and the carrier you choose for delivery.

You can pick different features to be included in the final product i.e. number of copper layers, substrate material, maximum dimensions of the PCB, dimension tolerance, and board thickness, making sure you get exactly what you ordered online.

The commitment of JLCPCB is second to none and we’re not even bragging since the hundreds of thousands of satisfied customers are solid proof of their durable and long-lasting products stuffed with innovation and precision.

Plus, they also offer a PCB Panelization service which suits you best if you want smaller PCBs with unusual shapes in bulk orders. This will not only save money but also ensures an efficient manufacturing process with a durable product.

2. PCBWay

PCBWay is another top-notch PCB prototype and fabrication company. They are committed to satisfying customers around the world with reliable circuit boards where the final product goes through advanced testing and inspecting equipment including an X-ray inspection machine, automated optical inspection machine, and flying probe tester.

They are equipped with online pricing software where you can get a rough estimation of the PCB you want to be manufactured. In addition, they also offer a PCB assembly service for successfully mounting the electrical components on the board.

Know that with PCBway, you’re in direct contact with the company as they are not a broker and you’ll get standard PCBs at an economical price with no extra charges. Moreover, you can monitor order fabrication and processing status online to make sure you’re not left behind in the process.

Different types of circuit boards they produce, include: standard PCB, multi-layer PCB, flexible PCB, rigid-flex PCB, rigid PCB, high-frequency PCB, thick copper PCB, HDI PCB, LED PCB and aluminum PCB.

3. AllPCB

AllPCB is a PCB fabrication company that provides customized integrated solutions to meet your electronic needs. They carry high-precision processing equipment that guarantees flawless operation where every PCB goes through strict 100% AOI testing and ruthless inspection.

If you’re looking for reliable and top-notch PCB fabrication and PCB assembly service, your search is over since AllPCB is there to help you deliver durable PCB exactly meeting your needs and requirements.

Normally, they ship the finished product within 3-5 business days, however, it also depends on the complexity of the order and the shipping cost may vary based on the size, weight and destination of your circuit boards. Furthermore, they also offer PCB Panelization which helps you place an order in bulk for the small-sized PCBs that saves both cost and time for the manufacturing process.

4. PCBgogo

PCBgogo is a highly specialized PCB Prototype Company, providing state-of-the-art medium and small-volume PCB fabrication. They adhere to the strictest standards in manufacture and assembly and also come with ISO 9001:2015 quality management system.

Introduced in 2017, PCBgogo is UL certified which guarantees the product’s reliability with a careful inspection where all circuit boards are thoroughly tested before being delivered. They carry the latest professional production equipment to ensure a seamless PCB and PCBA manufacturing process.

Moreover, you cannot only track your PCB and assembly order status online but also get notified of the manufacturing process and the shipping status of your order. An instant online quote option is available that comes with a transparent price structure making sure you get the final product with the exact features that you ordered online.

PCBgogo believes in 100% customer satisfaction instead of merely meeting financial goals. The fastest fabrication time is 2-3 business days, however, you can expedite the process and make it 12-24 hours on demand.

5. Atechcircuit

Founded in 2003, A-tech Circuit specializes in fast PCB prototypes, PCB manufacturing, and assembly services. A large inventory of stock PCB helps them cover a wide range of industries including telecommunication, aerospace, medical, automotive, and more. The staff contains highly trained experts that go the extra mile to comply with your PCB requirements. Customer satisfaction is their priority and they make sure you come back again and again for what they have to offer.

Their products and services are 100% in compliance with IPC-6012 & IPC-A600F standards and they are ISO9001:2008, ISO14001, TS16949 and UL certified. The types of PCBs that A-tech Circuit manufactures are rigid-flex PCB, flex PCB, FR-4 multilayer PCB, microwave PCB, metal core PCB and HDI PCB, so you don’t have to search for a new manufacturer for your electronic projects.

6. Unimicron

To meet the increasing demands of circuit boards in consumers’ electronics, Unimicron is another leading PCB fabrication company in the club. They are committed to designing customized PCB designs with an additional focus on maintaining the efficiency of the product with an efficient manufacturing process.

Started in 1980 as a small sheet metal and stamping company, Unimicron has not only continually evolved but also welcomed innovative ideas to manufacture and prototype circuit boards and make them align with the customer’s demands.

Moreover, high-end materials and sophisticated advanced technology are always considered in the manufacturing process. Unimicron has recently participated in new product and technology development projects with research institutes including IZM in Germany and Georgia Institute of Technology in the USA.

In November 2020, they received the “National Occupational Safety and Healthy Award” which is a helpful clue on how safe and secure is their production equipment.

7. PCBCart

Established in 2005, PCBCart is a professional PCB production service provider that takes pride in providing outstanding service in more than 80 countries around the world. Apart from high-quality PCB fabrication, they also offer PCB assembly and components sourcing services.

It is a one-stop production solution to your electronic needs serving companies of all sizes. Plus, they also offer an option to order a sample before you order in bulk, making sure you get the exact product meeting your needs and requirements. The manufacturing process is transparent and clear and you’ll never be left in the dark, as you can monitor and track your order in action and the processes it goes through before the final product is ready to deliver at your doorstep.

In PCBCart, the PCB fabrication complies with IPC 2 as quality grade, while PCB assembly is with IPC 3 and they follow strict manufacturing guidelines to ensure the reliability and functionality of products, including ISO9001:2007, TS16949, UL, RoHS, etc.

8. Zhen Ding Tech

Zhen Ding Tech strives to provide multiple customized solutions to customers around the world. The company serves a range of industries and electronic companies including IoT, Artificial Intelligence, 5-G technology, aerospace and military.

Every step in the manufacturing process follows strict guidelines, ensuring the precision and accuracy of the finished product. Use of automated production lines to ensure seamless production and on-time delivery put this company ahead of the curve.

Another aspect you may want to consider before hiring the PCB fabrication company is the qualified and trained staff. Zhen Ding Tech comes with highly skilled professionals that not only help you in the design process but also provide valuable suggestions in picking the right circuit board for your application.

9. Suntak PCB

Founded in Shenzhen in 1995, Suntak PCB is another top-notch PCB manufacturing factory on board. The company adheres to bringing in new trends in PCB design capabilities to stand out from the crowd.

As a full-category PCB manufacturing group, Suntak PCB makes PCBs that are used in communication equipment, smartphones, and automotive electronics. In the last two decades, they have established long-lasting relationships with world-renowned communication equipment manufacturers by providing customer-centric and impeccable service.

We love their mission, value and vision statements that put customers first by providing rugged and firm products using advanced and cutting-edge technology.

10. Kinwong

Kinwong is a PCB fabrication company that works ahead with clients to provide customized circuit boards for the development of the electronic project. Founded in 1993, Kinwong is the world’s leading PCB manufacturer that owns 5 production bases and 11 factories in China. The company is committed to serving its customers with more than 13000 employees worldwide.

With the main focus on incorporating innovation with the latest technology, Kinwong is specialized in producing automated circuit boards to make the electronic device thin, robust and lighter. They are one of the few domestic manufacturers that handle metal base PCB, flexible PCB, rigid PCB and rigid-flex PCB.

They have a dedicated department that is responsible for the systematic management of suppliers, ensuring a quick and automated supply chain for the prompt production of circuit boards.

Conclusion

Not all PCB manufacturers are equal. Some are better than others. We’ve shortlisted the top 10 manufacturers online that you can pick from. Again, it is advised to do your due diligence and gather enough information about the company you want to work with, this will not only save time but keep you from a lot of trouble later.

That’s all for today. In the next tutorial, we will have a look at the Top Circuit Simulators. Hope you’ve enjoyed reading this article. If you have any questions, you can approach me in the section below. I’d love to help you the best way I can. Thank you for reading this article.