Technical Guidance: Character Design Specifications

In order to facilitate component assembly, future maintenance, and traceability of PCB manufacturing information such as the manufacturer and production date, various characters are typically silk-screened onto the PCB.

Traditional PCB character silk-screening is produced using a screen printing method (hence the term "silk-screen characters"). In addition to the standard "silk-screen characters," JLCPCB also offers options like "high-definition characters" and "high-precision characters," which can be selected by the customer in the ordering interface. The differences are as follows:

1. Character Size Parameters:

The character line width and character height should be proportionate. There should be an appropriate gap between characters, and linear character widths are preferred over outlined character widths.

❶ Standard Font: Character stroke width ≥ 0.15 mm, character height ≥ 1 mm (high-precision characters supports a minimum character stroke width of 0.1 mm and a minimum character height of 0.8 mm).

❷ Hollow Font: Character stroke width ≥ 0.2 mm, character height ≥ 1.5 mm.

[Special Note] If the dimensions fall below these parameters, JLCPCB's engineering team will not adjust the character height in the files, but they may adjust the character width appropriately. Complaints related to unclear or blurry characters due to exceeding production capabilities will not be accepted.

2. Character-to-Solder-Pad Distance:

Characters should not overlap solder pads. Characters should be at least 0.15mm away from solder pads, with a gap of more than 0.15mm between character lines.

[Special Note] If the distance is less than this parameter, JLCPCB's engineering team will directly remove the characters on top of solder pads to avoid issues like solder bridging during SMT assembly. Complaints about characters missing due to this will not be accepted.

3. Treatment of Characters on Copper Surface:

Characters over exposed copper, tinned or gold-plated, will be removed directly.

4. Treatment of Characters on Substrate:

Characters on substrates with no copper (whether with or without ink), will be retained entirely.

5. Special Character Design Instructions:

To avoid interfering with component assembly, characters overlapping with solder pads or copper areas should prioritize exposed copper solder pads or copper areas (meaning the removal of characters from the copper surface). For customers with specific character requirements, you must ensure that the characters are printed on exposed copper solder pads or copper areas. Please make clear remarks when placing your order and confirm the production draft for the final result.

Example: Please specify in remarks “allow characters XXX to overlap with the solder pad.”

Once again, without specific instructions when placing the order, characters overlapping with solder pads or copper areas within 0.15mm will be removed.

Attention to these details is crucial, so make sure to communicate these requirements to your PCB design team. Don't simply provide files without conveying this information. The image below is an example of the default process where CAM engineering directly removes the corresponding characters in the window area.

Image shows the comparison between the original draft and the production draft.