PCB Board Design: 4 Simple Steps to Make Sure its flawless fabrication
Hello everyone, I hope that you all are doing good in your life. The topic for today is PCB board design. As we all know that PCB designing is one of the most trending topics nowadays, as It is widely in use in the manufacturing industries for example in manufacturing Medical devices, LEDs, Aerospace components, Automobile components and etc. Thus it is very important to learn its way of designing, But first, we have to understand what it is? what are its features? and then can move to its step-by-step development process. So now let’s jump into the contents of the blog without wasting much of the time.
What is a PCB design board?
Basically, a PCB (Printed circuit board) is the structure that is design to provide mechanical strength and electrical connectivity between the electronic components (for example a resistor, an inductor, a capacitor, etc.). Metal name solder provides the connection and strength to the PCB board. These design boards bring the connection routes to physical form by using tracks and pads.
In the designing process firstly with the help of layout programs or software (like Eagle), an design is developed, and then; with the help of special printers like plotters the layout is is physically obtain. A PCB provides a specific path for the flow of current or power between the components.
Components of PCB Board design
It is usually in a form of flat laminations with alternate layers of different materials mainly copper. The design can be as simple as consisting of only a single layer However, the copper traces can be available on either the side of the board i.e. front and back. Or maybe complex to a level that it contains about fifty layers or maybe more. There are six fundamental components of a PCB board.
Prepreg
A prepreg is a thin (dielectric material) fiberglass which is cover in dried resin. The resin used for covering is dried by not allowed to solidify. So that, when the design is ready for printing the resin, is exposed to a very high temperature that it melts again and acts as a glue for the components. Thus we can say that the prepreg job is to bind the core elements together. The resins which are most of the time in use are FR4 epoxy, Teflon and etc.
Laminates
Prepregs is the fundamental material that is used for manufacturing laminates. It is nothing but a kind of collection or layers of prepreg sheets with copper sheets on both sides.
However choosing the correct type of laminate is quite essential as it is the key to lowering the power losses, maintaining stability and etc. Factors that we should consider while selecting a perfect lamination are the Dielectric constant, Thermal resistance, loss factor and etc.
Copper
As mention above two thin copper layers are use to sandwich the lamination in between. However in a single layer, PCB copper is only present on a single side. This type of single-layer PCB is applicable for low-cost devices. Besides the copper thickness can vary from application to application.
Soldermask
The soldermask is the sheet or the layer present above the copper lining. It is mainly of green color and used for insulation of the copper trace. It also helps in providing mechanical strength to the PCB. The green insulation covers up all the main pads keeping the silver slots as opening the soldering.
Silkscreen
The silkscreens are nothing but a means of notation that is use for marking the silver opening available for soldering. We can say them as an indicator by better understanding. The silkscreen may contain letters, numeric values or symbols.
They are mainly white in color but can be of any as per the choice. The silkscreens also go by the name nomenclature.
As the soldermask provides the necessary security or say the strength to the internal of the PCB however the silver holes are left open in between for the soldering purpose thus to protect this opening; they are cover in a metal coat to provide better finishing.
Fabrication of PCB Board
The process of manufacturing PCB boards is very simple and it is very essential for a person involves in the electrical industry. Further below all the steps are mention one by one for understanding its fabrication process.
Designing
The first and foremost important step is designing the layout of the PCB. Initially, we need to design the blueprint as per the requirement of the customer or the application. These checks are usually done by the software itself.
While designing the blueprint all of the points such as track width, pad size, and other components are consider at the start only so the wiring and usage get easy. The most common software is Extended Gerber. Once the design is re-check and confirmed by the engineer and the customer the design is further sent to the printing house.
Printing the Design
After the approval of the design, it gets ready for physical printing. Special printing techniques called plotters are require for this process. This plotter develops a thin film of PCB in a dark, temperature control room. This film is nothing but a negative photo of the board itself. To write this on the films a layer is use.
However, each PCB layer along with its soldermask gets an individual film. This means that a single-layer PCB board design will have two films and a two-layer PCB board will have four sheets and so on.
After the printing of the films, they are align in order and holes are drill into them. These holes are for the means for the alignment of the board.
Printing of copper to the inner layer
Once the printing of the layout is complete, then the actual development of the board starts. Initially, the copper is pre-bound to the first layer, and then etching takes place leaving back the blueprint.
The next photosensitive sheet (resist) is use to cover the laminate. The resist is a type of material that hardens when exposing to UV rays.
Once the resist sheet and the laminate are align with respect to the holes from the last step, they are forged with UV rays. So that the resist layer gets hard and the rays can easily pass through the laminate. This denotes the region of copper that is to be kept open as a track.
Thereafter once, the board is ready, alkaline solution and pressure wash are use for washing it so that any of the un wants of the resists gets wash away. After washing it is dried and send for final approval.
Etching the core
The core of the PCB board needs to remove some extra copper sheets before completion of the manufacturing. Thus for the removal of extra copper etching is use. In this process, all of the unnecessary copper is cover with the etching chemical which removes all of the unnecessary parts. Leaving back only the require track of copper.
This process may differ from application to application. For large-scale applications, the copper requirement is more and for small scale, its requirement is less. More copper-containing sheets will require more etching chemicals and more effort.
Conclusion
However, here we are at the end of the blog. In this blog we have gone through manufacturing of a single layer PCB board design in depth with its step by step process. We hope that you like it and is satisfy with the content. If you do like the article then mention the part which you like the most. Besides if do have any doubt regarding the topic then feel free to ask down below. And also suggest the topic that you would like to read next on.
Regards;
Have a nice day 🙂
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Very helpful.