Prototype printed circuit boards, or prototype PCB, are the first version of the things that mechanically support and electrically connect things like computers and other technological devices. Prototype PCBs can be single sided, double sided, or multi-layered. In 2012, the world market for PCBs reached about $60 billion. According to IPC?s World PCB Production Report for the Year 2012, that includes 1.7% of real growth over 2011.
On a basic level, there are two methods used for assembling a printed circuit board. Surface Mount Assembly and the other is known as Through Hole Construction. Prototype PCBs consist of copper sheets laminated onto a non-conductive substrate, pads, tracks and other etched features.
The prototype PCB manufacturing process is long, complex, and can vary depending on the specific process, but there are a few general aspects that almost always apply.
- Panelization: Panelization is, essentially, when multiple prototype PCBs are put together to form one big panel. Manufacturers do this so they can more easily and readily ship the desired amount of PCB boards to their customers. After they receive them they can then undergo the process known as depaneling. Many times the manufacturer will include perforated edges for convenience.
- Copper Patterning: In order to properly replicate the desired fabricator’s CAM system pattern PCBs use layers of copper foil. This copper is then etched down. After that the board will undergo specific processes depending on the desired outcome: silk screen printing, photoengraving, PCB milling, and laser resist ablation.
- Chemical Etching: Chemical etching is used to remove other unwanted copper remains on the board and under the resist that can cause problems with the materials integrity/quality. This is typically done with ammonium persulfate or ferric chloride.
In addition to these steps, there are a variety of soldering methods that can be used to attach components to a PCB. SMT placement machines and bulk wave soldering or reflow ovens typically are used for high volume production. On the other hand, skilled technicians are able to solder very tiny parts (for instance 0201 packages which are 0.02 in. by 0.01 in.).
There is so much more that goes into this complex process, but this is a good starting place for printed circuit board prototypes.