What’s PCB printing and how are they fabricated?
The fabrication of a PCB is a complex process, but we’ll briefly explain how it’s done:
By using one of the many PCB design software packages available, the designer creates a PCB layout that fits all the required components in order for the design and product to function. The most popular PCB design software worldwide is Gerber X2 (or IX274X).
These Gerber files allow the designer to encode all of the important design information, like copper tracking layers, drill drawings and component notation. While the software also checks the design to spot any errors.
Once we receive your Gerber files, we usually perform “Design for Manufacture” (DFM) checks on the PCB data we receive, to ensure that our production capabilities (like minimum required hole sizes or space between tracks, for example) fulfill the requirements of your project. If you want us to design your PCB from scratch, then we can bypass this step as we will design the printed circuit board assembly to meet your specifications, as well as our manufacturing capabilities.
Plotting a PCBA film
Before fabricating the PCB, we use a laser photo plotter to print a film that acts as a negative for each layer of the PCB. This film is kind of like a map that shows where the copper will go when printing the copper foil. This is done in an environmentally controlled dark room.
Printing and etching
Now it’s time to make the actual PCB, there are many core substrate materials that can be used, usually an epoxy resin with a copper surface bonded on both sides. This panel receives a layer of photoresist, which is a photo-sensitive film that hardens after exposure to UV light.
We then proceed to print the PCB, by exposing the board to powerful UV lights which harden the photoresist through the clear areas of the previously printed film, while the black areas of the film protect the copper underneath it.
Then, an alkaline solution is applied to remove all the unhardened photoresist. This process is called etching. After a few examination processes, and removal of any unwanted copper, we get the exact pattern we want for your PCB.
Layer alignment, inspection and bonding
We now proceed to punch the layers, this way we make sure that each layer is aligned through the board’s registration holes, by using a machine called the “optical punch”.
After the layers are aligned, we proceed to verify that the board is free of errors with the initial Gerber files received using a laser sensor.
At this moment, the outer layers are bonded to the substrate by using a press that uses heated press plates and pressure to bond all the components together.
Drilling and plating
By using the CAD information from the PCB, a computer-controlled profiling and drilling machine proceeds to drill the holes where the components of the PCB will go. To provide conductivity between all copper interfaces, more copper is then plated into the holes by a chemical immersion process.
The process is a bit more extensive and detailed than that (some might consider it boring, but we don’t!) but here are a few more of the steps we go through to create a fully functional PCB. We’ll just list them here for brevity, but if you need more information just let us know:
- Second stage unneeded copper removal.
- Photoresist is added and cleaned again by another etching process, to ensure full connectivity between components.
- A layer of coating is added to protect the PCB from environmental factors.
- The legends and nomenclature are printed into the board.
- Profile milling of the board to get the desired contours.
- Additional surface finish by chemical plating.
- Final testing and inspection.
- Vacuum packaging and delivery.
The manufacturing of each PCB is an extensive process that requires a lot of expertise and attention to detail, and an important part of having a successful electronic production run is to use reliable firms to produce your electronics. Through years of experience, we have built a lot of trust with companies needing product prototyping and manufacturing services, so you know that if you work with us your PCBs will be created to the highest standards.