In this section we will discribe about how 4 layer PCB is menufactured with step by step
step -1 Garber file Generation
The board designer prepare his layout on a Computer Aided Design or CAD system. Each CAD system uses its own internal data format, so the PCB industry has developed a standard output format to transfer the layout data to the manufacturer. . The Gerber files define the copper tracking layers (4 in the job we are following) as well as the soldermasks and component notations.
First They (menufacturer) check that data meets to their manufacturing requirements. These checks are mostly done automatically. The checking processing include checking track width, space between tracks pads , holes , vias ,smallest size possible for their machine ,components and their alignments The engineer can also check and measure individual areas where he wishes. Once the data is verified as good he will output all the tool files needed to drive the machines that will make and test the PCB. here is the video explaining all
step-2 Phototools for PCB image transfer
Like in some offset press and printers the designed image (circuit) need to be printed in the copper board for this they prepare thin plastic like material for transferring the circuit to the board .All the process inside the PCB house is fully automated . so that they could produce mass amount of PCB in within limited time .
step-3 Innerlayer imaging
In this step they first image the inner thin layer of the PCB before that cleaning the board is essential .In this step first board is laminated so that desired location can only be printed on the board . then some photo making machine is introduced to capture the image on the board , all the process are done in a dark room , like old camera filming process .
step-4 Etching inner layer
After printing the circuit in the board , we need to remove unwanted copper on the board so that the exact wire will be setup on the board like circuit that have printed on board .
Step-5 Registration and inspection of inner layers
after completing the inner layers . They need to be punched so that a compact board will be formed . the registration holes in the designing part will use to align the inner layers to the outer layers. The operator loads the core into the optical punch which lines up the registration targets in the copper pattern and punches the registration holes with the punching and registration machine so that exact point can be punched .
step-6 lay-up and bond
After step-5 , after aligining the board to the registeration and inspection machine they need to be bond to make a single board , All this process is computer controlled
And similar process is repeated for outer layers and then finally gold plating in required area and silk screening ( component naming ) is done by using similar printing machines . And then export quality board is ready for packing and labeling . Here Full version some extended virson of The production line is described in the video below .