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What is Printed Circuit Board?

Written By Mohammed SHAFI

feature image of printed circuit board

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A printed circuit board or a PCB is a device that is used to mechanically support and electronically connect electric components by using conductive pathways.

PCBs are a part of our daily lives as they have become widely important in manufacturing companies to ease the production process. Everything from mobile phones to laptops is made using PCBs, which is why you need to know everything there is to know about them.

In this article, I am going to highlight everything that you should know about PCB design.

Printed circuit board
Printed circuit board, By Raimond Spekking

Things You Should Know Before Starting PCB design

There are a couple of things that you should keep in mind before designing PCBs. Here are a few of them.

PCB size:

The first thing that comes into play is the PCB size. The size of your PCB depends on the size of your product.

So, before you determine how big or small the PCB should be, you should take a look at the size of the product you are designing that PCB for.

For example, mobile phones have smaller PCBs compared to the ones installed on laptops.

PCB layers

On the other hand, the number of layers in the PCB design determines how complex a PCB is going to be. In the manufacturing process, the designer takes the product complexity into account and designs a PCB to meet the needs.

However, that doesn’t mean that a PCB with a single layer is not complex. The more layers we add to a PCB, the more complex and costly it gets.

Usually, two layers are used for simple toys, and up to 8 layers are used for smartphones.

Moreover, before you design a PCB, you need to ask a few basic things from the client.

For example, you need to know about the number of layers, the material of PCB, thickness, color, weight, and Gerber file so that all the requirements are met.

As the PCB manufacturing process is very complicated, you need to be very careful when designing them. While they are mostly used as the basis for electronic circuits, they are also used to provide a mechanical basis for products and circuits.

PCB Manufacturing

A PCB can be designed in several ways, the most prevalent of which are mentioned below.

PCB constituents

The first part that you need to figure out is the material you will use to make the PCBs. As they can be made from a variety of substances, you have to choose one that offers a degree of stability and is also durable.

Depending on where you are going to use the PCB, it might have to endure extreme pressure, which is why you need to be careful when manufacturing them.

So, you have to come up with a material that is not only perfect but isn’t much expensive. Most commercial PCB designing industries use cheaper material so that they can produce low-cost products.

However, if you want a balance between expense and durability, you can have a look at the PCB designs by the MKT factory.

Chemical Etching

If you want to create PCB with tracks for the components, you have to obtain a copper clad board first.

After you have chosen the PCB boards, you have to create the required tracks on the board and then remove whatever copper is left. This process is usually done using chemical etching.

Ferric chloride is the most preferred etching material, so you can use that to get clear etchings.

Photographic Process

Now that you have made clear markings with etching, to get the correct pattern of the tracks, you have to use a photographic process.

In this process, the copper on the PCB is covered with a thin layer of a photo-resist material. The PCB is then exposed to light, which passes through everything except the photo-resist material, and hence, the pattern of tracks.

After the imaging is completed, the photo-resist material is placed in a developer so that we can obtain the areas where the tracks are made.

Placing PCBs in Etch

Last but not least, the printed circuit boards are placed inside ferric chloride or your preferred choice of fetching material. This stage is used to etch the areas of the PCB where there is no track of copper.

After you have determined the concentration of the ferric and the thickness of copper on the PCB, the material is dipped.

However, you have to make sure that you place the PCB inside ferric chloride for a specific period, or else you will not be able to get an outline for untracked areas of copper.

Other Methods of Manufacturing

Where most of the manufacturing industries follow the process mentioned above, there are other methods of producing PCBs.

Another popular method of PCB board manufacturing is by using a specialized, highly accurate milling machine. Just like the photo-resist material is used to control the area where tracks have to be made, in this method, the machine is controlled to mill the copper where it is not required.

However, there is no mechanical control of the machine as everything is automated through software so that maximum precision could be achieved.

This method of production is not ideal for large orders as it takes more time to produce PCBs. But, if you have a special design request for PCB, milling machines can come in very handy.

PCB Prototyping

A very important part of any development process is to make a prototype before making the actual product.

Just like it wouldn’t be feasible to spend a huge amount of money on a project before making sure that it works, you should not waste money designing PCBs before making sure that it does what you want it to do.

So, before you begin with the production process, you should test the circuit board. Usually, you would want to get all the client’s requirements and get a prototype up and running as soon as possible.

You should then test the prototype for any limitations and ensure that you don’t make any big changes or introduce new elements during the final product.

The Bottom Line

The PCB manufacturing process is very complicated but is an essential element of any electronics or mechanical production lifecycle. The advancements being made in technology has initiated a lot of improvements in the production of PCB and optimize their manufacturing process.

If you follow each step religiously and make sure that you are making sure of the latest tech and technology, you can reliably produce premium quality circuit boards.

References:


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About the Author

Mohammed SHAFI

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Mohammed Shafi is the Founder of Mechanical Students. Also, he is the Lead Content Writer of MS. He also holds the position of Assistant Professor at Sreenidhi Institute of Science and Technology.

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