PCB Silkscreen
PCB silkscreen is the printed text, symbols, outlines, and reference marks on the PCB surface. It helps identify component locations, polarity marks, company names, part numbers, and assembly information. In many PCB designs, silkscreen is used on the top layer, bottom layer, or both.
What Is PCB Silkscreen?
PCB silkscreen, also called legend, is the printed marking layer on a circuit board. It is commonly used to show component reference designators, polarity indicators, logos, warning text, and other assembly or identification information.
Silkscreen does not carry electrical current. Its main purpose is identification, readability, and assembly support.
Copper is for electrical connection.
Solder mask is for insulation and protection.
Silkscreen is for text, symbols, and visual identification.
Common PCB Silkscreen Options
| Option | Description |
|---|---|
| Top Silkscreen | Silkscreen printed on the top side of the PCB. |
| Bottom Silkscreen | Silkscreen printed on the bottom side of the PCB. |
| Top and Bottom Silkscreen | Silkscreen printed on both sides of the PCB. |
| Silkscreen Color | Common colors may include white, black, or other color combinations depending on solder mask color and process capability. |
Why PCB Silkscreen Matters
- It helps identify components during assembly and inspection.
- It improves readability for polarity marks, pin 1 marks, and reference labels.
- It can show board name, revision, logo, or tracking information.
- It helps reduce assembly mistakes when clearly designed.
Important PCB Silkscreen Design Notes
- Do not place silkscreen text or lines on exposed pads if readability is important.
- Very small text may become unclear or unreadable after manufacturing.
- Keep enough clearance between silkscreen and pads, vias, or solder mask openings.
- If silkscreen overlaps solderable areas, part of the silkscreen may be clipped or removed during CAM processing.
If a silkscreen item overlaps a pad or opening, the factory may remove or trim that part of the silkscreen to avoid manufacturing problems.
How to Choose PCB Silkscreen
In most standard PCB projects, top silkscreen is the common default choice. Bottom silkscreen may also be needed depending on the assembly or identification requirement.
When selecting PCB silkscreen, you should consider:
- Whether components are assembled on the top side, bottom side, or both sides
- Whether reference marks are needed for assembly or debugging
- Whether your board needs logo, revision, or warning text
- Whether silkscreen color needs strong contrast with the solder mask color
Common Questions About PCB Silkscreen
Why is some silkscreen missing on the finished PCB?
A common reason is that the original silkscreen overlapped pads, holes, or solder mask openings. In that case, part of the silkscreen may be removed during manufacturing processing.
Can I put logo and text on the PCB?
Yes. In many cases, logo, product name, revision mark, and simple text can be added through the silkscreen layer, as long as the design follows manufacturability rules.
Does silkscreen affect electrical performance?
Normally no. Silkscreen is a marking layer and is not used for electrical conduction.