As PCB is standard term in industry, it has various contents and parts which is quite often used for design by users, designed and prototype PCB manufacturers in industry. Standard terms help in common understanding and knowledge transfers. Let’s have a look on few of them:
1. Surface – Normally FR4 surface.
2. Trace – The copper wiring/lining or copper/conductive layer. Trace width is width of copper layer for wiring.
3. Plane – Normally refers to copper poured on PCB.
4. Layer – Copper film on PCB. This is conducting plane. Number of layers defines number of copper or conductive planes on PCB, using which it is designed. More the number of layers, complex is the PCB but smaller the size. From layer perspective, 3 commonly used terms are there – Single layer, double layer and multilayer (Multi layer is having more than 2 layers). Multilayer prototype circuit boards is used for complex interfacing, usually ICs with several connections. While components are placed on surface, interfacing is done on the inner layers.
5. Vias – These are holes on PCB surface which connects two layers (conductive planes). These holes are poured to make it conductive, so that they remain conducting. Vias can be covered or insulated using solder mask. An insulated via is called tented via.
6. Thermal padding – A metal distributed plane near a soldering pad. It is provided to distribute the soldering heat and momentarily heat can damage components pin/chip. This can be also distributed to form a heat sink.
7. Solder – conductive metal, which can be melted over high temperature and can add a pin to pad of PCB.
8. PADS – Soldering point. It is exposed metal on PCB, which is used for IC and components to PCB.
9. SMT – pcb board assembly. They are non drill and compact in nature used for SMD components.
10. DIP hole – Conductive holes through hole components.
11. Annular ring – This is copper ring around through hole. It can be on via or solder junction.
12. Slot – It is non conductive slot on PCB. It can circular or rectangular and can be used for mounting PCB in case or fixing components on PCB.
13. Test points (TPs) – These are open points where a probe can be put to check signal, power, etc.
14. CAD tool – Computer aided design used for circuit designing.
15. DRC – Design rule check. This is used by error check on designs like minimum size, overlap or any rule violations which can provide faulty manufacturing file.
16. Gerber Data – This is data for let’s say prototype pcb fabrication. This is standard industry term in industry and comes as output from PCB CAD tools.
17. BoM – Bill of materials, it contains all details of components of PCB. The main values are components name, value, quantity, supplier details, cost estimations, etc.
Whether you are a designer, manufacturer or user, if you have understanding of these terms, it will easier to communicate on design change, production phase, requirements, etc. A complete PCB lifecycle incorporates PCB design, PCB manufacturing, components sourcing, circuit board assembly and testing. PCB design is performed in CAD tools to generate Gerber data and BoM. Gerber data is used in manufacturing to create copper placements on substrate. PCB manufacturing is mainly a chemical process. Then components are soldered using solder and heating process. Assembly can be done using simple hand soldering as well as through automated machine process. Today, complete PCB manufacturing and assembly is an automated process and widely used for mass production in million quantities.