Introduction: Printed Circuit Boards
Printed circuit boards or better called PCBs are seen as an important component of the electronic items. This invention has found a place in almost all the electronics that work on computations which range from the simple calculators to other devices like that of the digital clocks.
Table of Contents
- Introduction: Printed Circuit Boards
- What do we Understand by the Term PCB?
- What are the Steps that Form Part of the PCB Manufacturing Process?
- PCB Manufacturing Process: Required Raw Materials and prerequisites
- PCB Manufacturing Factory: Required Machinery
- PCB Manufacturing: Required Licenses and Compliance
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The work of the PCB involves the routing of the electrical signals through the electronic item. This in turn satisfies the requirements of the electrical devices that might be mechanical or electrical. In short it can therefore be said that the PCBs play an important role when it comes to channelizing the electricity so that the electronics can be brought to life.
Printed Circuit boards in a way ensures that the current is directed around its surface with the assistance of different pathways involving copper. This copper network that has the complex system is a deciding factor that acts in determining the role that must be played by each of the pieces that forms the PCB circuit board.
What do we Understand by the Term PCB?
PCB is the short form for printed circuit boards. Electronic circuits forming a part of modern life are assembled with the help of such circuit boards. The design layout of the PCBs is in itself very much demanding, consisting of many layers of copper along with the layers that offer insulation. Signal traces form a part of these layers.
Most of the systems making a mark in modern life carry the capacity to have boards of at least eight layers. The PCBs design is equally important as that of the design of the circuit which would fuel the efficiency and performance of the entire system.
Certain effects associated with the PCB can possibly prove to be harmful which affects the performance of the circuit. These can include the following:
- Resistances in case of leakages
- Ground planes
- Dielectric absorption, etc
Further, the PCBs related tendency that works on absorbing the moisture present in the atmosphere simply stands to mean that the changes that occur in the levels of the humidity most often presents the related cause underneath the parasitic effects that can invariably vary on a daily basis.
On a general basis, the effects associated with the PCB can largely be looked upon as being divided into two main categories which are as follows:
- On the first hand, comes those that play the role in casting an effect on the circuit’s dc operation or that of the static operation.
- On the second hand, comes the category that casts a noticeable effect on the circuit operation which can be either the ac related or might be dynamic with a special focus at higher frequencies.
Another feather in the hat of the design of the PCB can be found within the topic that speaks of grounding. Grounding presents an area that can pose problems, especially when it's about the designs pertaining to analog signals and also includes the mixed signals. Therefore a conclusion can be made that if there takes place the implementation of the circuit design that is based on PCB, then it would not change the fact that still there is requirement of the proper techniques.
Irrespective of everything, the good thing is that there exists numerous principles pertaining to grounding that entail quality, to name them we can pinpoint to the utility of the ground planes, which form an intrinsic component of the PCB environment.
What are the Steps that Form Part of the PCB Manufacturing Process?
It is very crucial to note that before the work starts on designing the PCB, the circuit designers must acquire the requisite knowledge and pay a visit to the board shops that deal in the PC and also resort to getting in touch with the fabricators. This would open ways for meeting the demands that surface with respect to the manufacturing of the PCB.
In contrast to this, it is seen that many companies resort to outsourcing the inquiries related to the PCB manufacturing from the suppliers that are located overseas. This sounds highly impractical.
Given below are the steps that are involved in the manufacturing of the PCB:
- In the first instance, it is pertaining to the design and the much needed output. It is to be noted that there must be compatibility of the circuit boards with that of the PCB layout that comes into existence with the help of the PCB design software.
The PCB design software’s that are most commonly used includes like that of the Eagle, and Altium Designer etc. In addition, the design is exported by the designers, in event the PCB design has very well received the approval for the production to take place. It is to be remembered that the design involving PCB is required to undergo a check.
It is the function of the PCB design software that looks after the design so that it is assured that no error is left undetected. Besides this, the plan is thoroughly examined by the designers that involves the elements regarding the width of the track and the size of the hole etc.
Once the examination has been done, the PCB file would be forwarded to the board house so that the production could be carried out. Design for manufacture check would form an essential component prior to the fabrication of the circuit board. This would ensure that all the requirements pertaining to the design would be fulfilled in respect of the tolerances while the process of manufacturing takes place.
- Under the second step, the PCB printing would follow, preferably after the DFM check has been conducted by the manufacturer. A unique printer, which is called a plotter, is used by the manufacturer so that the circuit boards can be printed. This unique printer is employed to give effect to the photo films to come into existence.
The photo films would be invariably used by the manufacturers to image the printed circuit boards. Even though the plotter can be looked at as a simple laser printer, it cannot be construed as being a standard one.
Printing technology that is used by the plotter is no doubt a very precise one that puts forth a film of the PCb design which is very much a detailed one. As regards to the final product, the result appears in the form of the plastic sheet together with the PCBs photo negative that is present in the black colored ink.
In respect to the inner layers in the PCB, its copper parts that are conductive are very much represented by the black colored ink. The non-conductive material is represented by the remaining clear portion. Opposite pattern is preached by the outer layers.
The film is developed by the plotter in an automatic fashion and thereafter in order to get rid of any undesired contact, the film is stored in a secured fashion. Black colored film sheet is received by every individual layer forming PCB along with the solder mask.
If computed on a total basis, it can be said that there is a requirement of four sheets in two layered PCB. More importantly, there must be a perfect correspondence between all the layers of the PCB. The PCB alignment could be mapped easily when all the layers are used in a fashion that involves harmony.
All the films must entail the registration holes, punched into them so that a perfect alignment is easily achieved. The process of adjusting the table could trigger the exactness of the hole. The hole gets punched in the event wherein the optimal match is met by the table’s calibrations which are indeed tiny.
- Then comes the third step. This step involves the printing of the figure onto the film which is present on the copper foil. This is one of the most important step forming parts of the PCB manufacturing process which fuels the PCB to take the actual form. Laminate board is the part of the PCB which is present in its most basic form.
Epoxy resin is construed to be the core material of the laminate board together with the glass fiber, both of which are a type of substrate material. Laminate board is considered to act as an ideal body that is fit to receive the copper which in turn serves the purpose of giving a structure to the PCB.
A sturdy starting point is provided by the substrate material in view of the PCB. Both the sides entail the presence of the copper that is pre-bonded. The copper is whittled away in the process so that the design could be revealed from the films.
Cleanliness is not an issue when it is about the construction related to the PCB. The laminate is cleaned thoroughly and thereafter allowed to pass into an environment that is very much decontaminated. During the ongoing process of this stage, it is indeed important that the laminate remains free from the particles of the dust. Even a speck of dirt can become the reason behind the short circuit.
Following the above mentioned step, the panel is subjected to the photoresist which is basically the layer that consists of the film that is photosensitive. The photoresist is composed of the layer that contains the photo reactive chemicals. This chemical hardens up when it is exposed to ultraviolet light.
Once it is made sure that the board is totally prepared then in the next step, the alkaline solution is used that washes out any photo resist that is left in the unhardened form. Finally the pressure wash is employed to wash out any other impurity from the surface of the board. Subsequently, the board is then left so that it can be dried.
The board is then examined with the help of the technician that makes sure that there is no scope for the errors to surface. It is to be noted that this step is only applicable in case of the boards that entail more than 2 layers.
- The board is then taken to altogether the new step. This step basically involves the removal of the copper that is unwanted. Excess amounts of the copper is eaten away with the help of the complex chemical preparation.
The exposed copper is easily removed with the assistance of the copper solvent solution. Simultaneously, the copper that is very much desired falls under the umbrella of protection in the form of a hardened layer containing photo resist.
It needs to be highlighted that it is not important that all the copper boards would be created on an equal basis. To justify this, we can say that in case of the boards that are heavier, they ask for an enormous amount of the copper solvent and in many cases exposure is required at varying lengths.
Moreover, the heavier boards require attention with respect to track spacing. In most of the cases, the standard PCBs are very much reliant on the specifications that are similar. Ultimately the final output would showcase the board that would only have the substrate of the copper which is very much vital for the PCB.
- This step requires the layers to be in perfect alignment. The registration holes serve the purpose of making sure that the inner layers are well aligned to the outer ones. Thereafter the layers are placed by the technician in the machine known as the optical punch.
- During this stage, it is all about the circuit board taking the final shape. Now comes the right time to give effect to the fusion of the layers. This is done by the layer up process followed by bonding.
- Under this step, the holes are drilled into the stack board with careful input of precision. The drill’s movement is overlooked with the help of the computer.
- Once the drilling is done, then the panel is gifted to be plated.
- Thereafter the PCB is covered within a layer of gold or silver.
- As a precautionary measure, the PCB is made to undergo electrical tests as performed by the technician.
- The very last step involves the cutting of the PCB board.
PCB Manufacturing Process: Required Raw Materials and prerequisites
There are certain raw materials and prerequisites that form the foundation for the manufacturing of the PCB. They have been jotted down below:
- In the first place, land is needed so that a factory can be set up that manufactures the PCB.
- Secondly, the substrate is needed that would act as the base material and would impart the required rigidity as needed by the PCB.
- Then comes the need of copper which is very much obvious. It is added to the PCB, especially to the functional sides.
- Thereafter the solder mask must be fetched which finds its place on the top of the layer of the copper. This would ensure that no shorting takes place and embellish the PCB with the green colour.
- Last but not the least, the silkscreen is needed. This serves as the final layer that is present on the PCB board.
PCB Manufacturing Factory: Required Machinery
To be able to set up the PCB manufacturing factory, few machinery must be fetched, which are given below:
- The very first machine is named as heatwave soldering.
- Oscilloscope also forms an essential machinery
- You cannot possibly think of the PCB manufacturing factory without having the generator
PCB Manufacturing: Required Licenses and Compliance
The PCB manufacturing process to take place in India requires certain licenses before launching the process followed by the need to adhere to the compliances. They are listed as below:
- In the first place, there is a need to acquire a tax registration certificate.
- Secondly, there is a need to have the organization code certificate.
- On an overall basis, there is a requirement of a certification system that is three tier based.
- Firstly, the license must pertain to the quality
- On the second basis, the license must pertain to the environment
- Next, the license should be related to the occupational safety
- Lastly, the certification must be acquired related to the health management system.
In the nutshell it can be concluded that if you are thinking of starting the PCB manufacturing factory, you must be sure that you get hands on the necessary machinery, land and the raw materials. Do not forget to fetch the vital licenses and stick to the compliances.
This portion of the site is for informational purposes only. The content is not legal advice. The statements and opinions are the expression of author, not corpseed, and have not been evaluated by corpseed for accuracy, completeness, or changes in the law.
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