An Introduction to PCB Manufacturing
A PCB, as any techies reading this will know, is a printed circuit board. This is the board that you will find in the vast majority of your electronic devices and gadgets. which is used to support as well as connect the various components. That is required for its function.
The ‘printed’ part of printed circuit board describes the pathways or ‘traces’ that run between those components and which dictate the way the components operate. This is normally accomplished by laminating copper sheets onto a non-conductive substrate (such as wood). Then scratching away the unwanted metal to reveal the desired pattern. This will then act as the circuits once attached to a power source (such as AA batteries). As you know can be used to accomplish a huge variety of ends.
This is a crucial element in a vast number of products, inventions, and creations and we owe a lot of our modern-day conveniences to the process. With that in mind then, read on and we’ll take a look at the process responsible for automating so many of our daily tasks.
When talking about the board on its own without the additional components that give the circuit its function. PCB is actually not the correct term. The board alone is known as a ‘printed wiring board’ (PWB) or an ‘etched’ wiring board (EWB).
The first stage in manufacturing these wiring boards then is to create an image of the wiring to work from using CAD software the same way you would make schematics for the part itself. This is your job as the inventor, so make sure that your circuit works by testing it with your breadboard or whichever set-up you have at home first. Next, you should do a ‘test print’ onto a sheet of paper using a laser printer.
Before the circuit itself is created, raw PC boards will first be loaded into a drilling machine which will drill the required holes where needed. These boards are usually made of glass-epoxy. And will have copper attached to either side (we’ll get to that in a moment). Silk screening will have been used beforehand to add company logos and another branding.
What you’ll be left with is a file that can then be used to recreate that circuit using conductive strips. And a board with holes drilled into it. This is usually accomplished through an etching process that uses a laminate material with sheets of copper already attached to both sides. This copper is then ‘etched’ away in order to leave only the desired connections and circuitry to connect the various components.
This etching, however, doesn’t resemble the etching you might have done at school. Rather it involves corrosive chemicals that can erode the copper where it isn’t wanted. First, though the desired ‘traces’ need to be protected.
This can be accomplished using a silk screen printing method for In large volumes. This is the main commercial method (here etch-resistant inks are printed to protect the copper foil). When the circuit boards are required in smaller volumes. The circuits will often be printed onto a transparent film to act as a ‘photomask’ before etching begins. In some cases, additive processes can be used wherein the copper strips are added to a bare laminate.