So basically you use a little bit of ink roughly where the typeface will be, when the laser melts the plastic, some pigment will diffuse into the melted plastic, but the unmelted/undiffused stuff is still removable.
If I had to guess this is how it’s actually done on the nicer older keycaps.
You’re right. The main challenge was just zeroing in on the point where the plastic softens to let the heated ink penetrate without deforming or burning the keycap. I think there’s potential here to do it better than I have, but I do think I landed on one of 2 or 3 different possible settings that will work decently well.
It’s a low-rent form of dye-sublimation, and I don’t know if they’re using lasers, but dye-sub is one of the preferred ways to add legends to PBT keycaps.
I imagine it’s order is:
Ink
Engrave
Wipe off excess ink.
So basically you use a little bit of ink roughly where the typeface will be, when the laser melts the plastic, some pigment will diffuse into the melted plastic, but the unmelted/undiffused stuff is still removable.
If I had to guess this is how it’s actually done on the nicer older keycaps.
Though I could be entirely wrong here…
You’re right. The main challenge was just zeroing in on the point where the plastic softens to let the heated ink penetrate without deforming or burning the keycap. I think there’s potential here to do it better than I have, but I do think I landed on one of 2 or 3 different possible settings that will work decently well.
It’s a low-rent form of dye-sublimation, and I don’t know if they’re using lasers, but dye-sub is one of the preferred ways to add legends to PBT keycaps.