SOLDER RESIST AND LEGEND PRINTING
A. Solder Resist (Solder Mask Application)
Purpose: Protects copper traces from oxidation, short circuits, and solder bridging during assembly.
Process:
1. Cleaning: The PCB surface is cleaned to remove oxidation and contaminants.
2. Solder Mask Application: A photosensitive solder resist ink (usually green but also available in other colors) is applied by spray coating.
3. UV Exposure & Development: The mask is exposed with an automatic UV Laser machine, hardening the printed areas.
4. Curing: The PCB undergoes heat curing to strengthen the solder mask.
B. Legend Printing (Silkscreening)
Purpose: Prints component labels, part numbers, polarity markers, and other identification marks on the PCB.
Process:
1. Printing Methods:
• Screen Printing: Traditional method for simple, large-scale production.
• Inkjet Printing: Precise, digital process for high-resolution markings.
• Laser Marking: Used for high-durability and fine-detail markings.
2. Curing: The legend ink is heat-cured or UV-cured for durability.
This phase ensures PCB protection, readability, and ease of assembly.
