Things to Consider when Buying Printed Circuit Boards
Hello, and welcome to another hub of mine about electronics.
In this hub, you'll learn what is involved in buying a batch of printed circuit boards for your future electronics project, from design to assembly. Let's get started, first some info for those who don't know what PCB are ( This guide is a rewrite of my own quick guide to buying printed circuit boards, available at PCB reference).
Printed circuit boards are made of laminates of insulating materials, often fiberglass covered with epoxy, that help the components that make a circuit have a firm base for soldering and use. The component connections are made with tracks that run on one or both sides of the board, and the contact points, called pads, are often drilled for the pins to go through and be soldered to the board.
The green color most people are familiar with is a protective layer called solder mask. This layer helps to protect the tracks from corrosion and wrong joints in the soldering process that could cause a short circuit or other malfunctioning. Most professional boards also use what is called a silkscreen, which is mostly used for drawing the outlines of the components or to write some trademark notice or other comments directly to the board.
So let's start with the ordering process. There are some things to do before you actually order the boards, one is to check if the manufacturer you are considering offers short runs or standard sizes, as that will allow you to buy a cheap set and not have to pay upfront for a large batch of custom boards when you only need one or two.
First thing to do is to have a circuit design and schematic, because why would you need a circuit board if you don't even have a circuit in the first place?. There are many free tools out there that will help you with creating your schematic, and I suggest you look for one that will allow you test and simulate the behavior of the circuit, and also to create at least one working prototype of your project to ensure that it will work before ordering your boards, because if the circuit is defective, a good board can't do much to make it work like its supposed to.
Now that you have your schematic and prototype tested and built, you need to actually design your printed circuit board.
This process can cover quite a bit of time and a lot of working knowledge of how the routing of the tracks affects the performance of your circuit, but for the first and simple circuits, it can be quite easy to do. There are many manufacturers that offer their own software solution for the design of the boards, make sure to check their sites for a download and instructions on how to use them.
Also note that since you most likely will be ordering one of their standard sized boards, you need to set the project for your design using those dimensions, or they may not be able to built it for the price specified, since they most likely will consider it a custom job.
One of the benefits of using software to design the boards is that the output files have been standardized to the Gerber file format, that is used for the plotters when actually printing the tracks on the boards, so any tool you use should have the option to export the design to said format.
Again, its time to double check your design, prototype and now the board layout, since any defects in this stage will cost you money on replacements if you discover them after ordering the boards, so make sure to get them right. After that, getting the boards is as easy as selecting the boards you want to order, upload the Gerber file and pay.
First thing to do once you have your boards is to check them for manufacturing defects and shipping damage, such as broken boards, holes not drilled or tracks incomplete or defective. Doing this before you start soldering the parts will allow you to have a replacement quickly in case of defect, while saving you money on replacements or having to desolder your work before sending in for replacement or refund.
Now that you have your boards safe and working, its time to actually build your circuit, which should work as you double and triple checked them before ordering the boards.
Having your circuit in a printed circuit board is a great asset to your project, as it makes them look professional and depending on complexity, even impressive by themselves.
Good luck in your projects, and have fun making electronic circuits!