Imagine that you have finished with laying out your board in KiCad and you’re ready to make it. What are your options? One option is to make your PCBs at home. There’s a guide available on the Fritzing website.
The process described in the Fritzing guide is called etching. It involves the use of various chemicals, in chemical baths. Some of these chemicals are toxic. You have to have special safety equipment, and keep your children and pets away. The process emits smelly and potentially dangerous fumes. Once you have your board etched, you still need to use a drill to make holes and vias, and then figure out a way to connect your top and bottom layers.
If this sounds like not your kind of thing (I’m with you!), then you can opt for a professional PCB manufacturer service. PCBWay, OSH Park and other manufacturers like ExpressPCB and Seeed Studio are very good at what they offer.
Professional PCB fabricators
You can get a professionally made PCB around $15 for several copies, and without danger to yourself as well. I’ve used OSHPark (great for beginners thanks to its straightforward user interface) and PCBWay (great for more advanced projects that need a large array of manufacturing options) extensively. I’m always happy with the result. Using an online manufacturer does take a little bit of planning because once you order your PCBs it can take up to several weeks for them to be delivered. If you’re in a hurry there are options to expedite the process if you are willing to pay a premium.
The typical small standard two-layer order costs around $10 for a two square inch board; you get three copies of that. This price works out to around $5 per square inch. The pricing is consistent in the industry, where the main cost factor is the size of the PCB. There is a strong incentive to make your PCBs as small as possible. Be aware of this when you design your layout.
Figure 3.1: An example of the Gerber files that the manufacturer will need in order to make your PCB.
Now, let’s turn our attention to the files that you need to upload for these services — and the files are Gerber files. Each layer on your PCB has its own Gerber file which is simply a text file. Figure 3.2 shows the contents of an example Gerber file.
Figure 3.2: Gerber files contain text
You can see that this is just a text-based file that contains instructions. An advantage of this text format is that you can use a version control system like Git and keep your projects stored in repositories like Github.com.
The Gerber files system and standard has been designed by Ucamco. They make equipment and write software for PCB manufacturers — things like a PreCAM software, PCB CAM, laser photoplotters and direct imaging systems. If you’re curious about how to read these Gerber files then you can look up the specification of the Gerber format specification on Ucamco’s web site. Beware, it’s a huge file.