Have you heard about the word PCB? Do you know how it is designed in manufacturing world? How do industries design it in a bulk quantity with higher quality and accuracy? First of all, we need to know about the designing techniques and practices. We are here to give you information about PCB designing. There are few steps that are needed to be followed carefully.
Copper clad plates are cut into desired size using cutting tool so that cost can be reduced. Now it is cleaned using water and scrubber. After that it is dried by heater for 5 minutes.
Stack and pin for drilling
do you know the meaning of stack? Stack is just the layout of layers like VCC, GND, used on PCBs in a sequential order for easy designing. WE can use two styles where first is a board with external pairs and second is a board with internal pairs based on core layer. A board with external pairs gives the idea about drill pins layer between copper layers on multilayer PCBs, a core for copper layer on the top and a core for bottom copper layer and a contrast at the center for the internal pairs style and we build core on the central layer outwards to exterior layers in the external pairs style. Power layers are assembled in a way so that power supply layer can be remain unused on rest mode conditions. We have to check the selected measurements of drilling holes specified ranges are used. We just need to select right measurements.
PCB boards are sticked together then CNC machine or drilling machine can be used to make holes on them according to the computer design which is called drilling process. Now we have to check the hole patterns carefully. Carbon is used to coat the drilled holes due to conductivity towards current flow.
As this term indicates a protective covering of transparent thin layer is used here before tracing required circuit image on special purpose cloth using CRG paper by covering the whole image. Now UV light sensitive plate is to be laminated by using CRG paper. This is a resist film towards copper bank.
Laminated circuit image pattern that is to be traced on special purpose cloth is placed under UV light or direct image using laser light to print the design on this cloth. Your track is ready to be traced on PCB board.
Printing circuit image
Now ink is used to print on PCB boards by placing the track on PCB board. Here we can see printed image on PCB. These inked PCBs are dried by heating using heater for 20-30 mins. As we know copper reacts with ammonia very easily, so here we use ammonia to remove copper except the mask portion where inked print is placed on PCB board. Ink is non-reactive to ammonia so copper under the inked part will remain on it. Now this is dipped in sulphuric acid to preserve this ink properly.
Removal of ink Traces
Caustic soda is used to remove inked traces by dipping for a while without scrubbing. If you do not have caustic soda you can just scrub it to remove ink until copper surface is seen properly. Put it into water for few minutes.
A layer of ink is exposed on PCB by using green ink and is dried in heater as mentioned above during tracking process, this process is known as masking in industry.
As we know copper get oxidised when explored to air which we do not want in case of PCB design. Tinning process is done by using to secure the copper circuit PCB board. Circuit is printed on the backside of the PCB board for easy understanding. Tin solder powder (lead free and >90% tin) with HCl acid is mixed together for overnight for best results. PCBs are immersed in this solution so that tin layer can be formed to protect from future chemical reactions with copper layer.
After completing the manufacturing process it is necessary to pack PCBs carefully. First of all, we need to check the damage before doing it. If there is no error on PCBs then it is ready for packaging. Here, we use vacuum seal packing method then boxes are used for final touch with required label marking on it with inspection then are delivered to customers on their doorsteps.