Dye-sublimation involves using high heat to transfer and permeate dye into the surface layer of the keycap plastic; the ink does not merely adhere to the surface but penetrates the material itself. This process is most commonly used for PBT keycaps.
Production Steps:
1. Keycap Molding
Blank keycaps are injection-molded using PBT plastic raw material. They are then cleaned to remove surface oils and mold-release agents, ensuring the surface is free of impurities.
2. Printing Transfer Paper (Film)
Using specialized dye-sublimation ink, characters, patterns, and side-printed designs are printed in mirror image onto dye-sublimation transfer paper.
3. Positioning Keycaps
The printed transfer paper (film) is aligned and pressed tightly against the keycap surface, with the patterned side facing the keycap wall to prevent shifting or air bubbles.
4. High-Temperature Thermal Transfer
The prepared keycaps are placed into thermal transfer equipment (such as an oven or heat press) and heated to temperatures between 180°C and 220°C.
At high temperatures, the ink sublimates into a gas; the dye molecules permeate the surface layer of the PBT plastic, fusing with the material.
5. Cooling and Film Removal
After heating, the keycaps are removed and allowed to cool naturally. The transfer paper (film) is peeled off, revealing the pattern now set into the keycap surface.
6. Post-processing and Quality Inspection
The keycaps are cleaned and inspected for pattern clarity, ghosting, color deviation, or misalignment. Defective units are discarded, and the finished products are finalized.
