What is PCB Silkscreen?
The silkscreen on a PCB refers to the layer of ink trace that provides essential information about the components and layout of the circuit board. These markings provide valuable information about component placement, test points, and warnings, which are crucial during both assembly and maintenance.
Common PCB Silkscreen Symbols and Meanings
Functions:
- Labels like : “R1” for resistor 1 or “C2” for capacitor 2.
- Indicate Test Points: Marks for test points facilitate troubleshooting and testing.
- Provide Instructions: Symbols or text that instruct on voltages or cautions.
| Symbol | Meaning |
| C | Capacitor |
| D | Diode |
| R | Resistor |
| U | Integrated Circuit (IC) |
| J | Connector |
| TP | Test Point |
| + | Positive Voltage Connection Point |
| – | Positive Voltage Connection Point |
How is the PCB Silkscreen process performed?
- Getting the Ink Ready: Preparing the ink based on the desired color and how long it needs to last.
- Making the Stencil: Designing and creating a stencil that shows what you want to print.
- Putting on the Ink: Applying the ink through the stencil onto the surface of the PCB. The steps include making sure the ink is the right consistency to print, lining up the stencil with the layout of the PCB, and using a squeegee in manual printing or automated equipment in a factory to put on the ink.
- Drying the Ink: Curing the ink so it sticks well and stays readable for the life of the PCB.
How to choose the best PCB Silkscreen color?
Pros and Cons of Different Silkscreen Colors：
| Color | Pros | Cons |
| White | High visibility on dark PCBs | Can get dirty easily |
| Black | Good for light-colored PCBs | Less visible on dark backgrounds |
| Red | Useful for indicating danger or power | Can be visually intense for some uses |
Typically, white ink on dark PCBs and black ink on light PCBs offer the best visibility. Depending on the end-use of the PCB, colors like red or yellow might be used to denote specific voltages or cautions.
