So this is a variation on dye sublimation, one of the main ways legends are printed onto single-color keycaps. The process is basically your second idea and exactly as @Uranium_Green says.
Coat the area in ink from a marker meant for permanently decorating cloth or various polyesterish plastics. The intended heat source is a glorified clothes iron made for DIY crafting.
Feed the Laser a simple bitmap image and run it low and slow, so it heats up the plastic but doesn’t melt or char it like on several of the earlier trials in that photo.
This should cause the heat-activated ink to integrate more or less permanently to the polyester-based PBT plastic. Then I clean off the unlasered ink with isopropyl alcohol and/or acetone. The zapped ink doesn’t fade at all, though as you can see it’s not super vibrant.
The sweet spot to do this without charring or melting the keycap is pretty small, though though there’s probably another configuration where you use higher power and quicker movement. There might also be one at even lower power and longer time. I’d seen several people try it, but with weird projects on cheap lasers you’ve typically got to find your own settings. Also, don’t laser ABS; very bad idea.
Awesome, thank you! I could have Googled this, but it is always awesome to get information from someone who can give a better summary.
Since you are closer to the laser etching/cutting aspects than I am (I have a traditional hobby CNC machine and do a ton of 3D printing), I am curious if hight mapping has been integrated into laser etching yet. The reason I ask, is that when I cut fine pitch PCBs, I need to be at very specific depths of cut, usually within 0.1mm or so when precision is required.
Working with small curved surfaces could be problematic for maintaining the correct laser focal point? Maybe? Possibly? Even applying a generic hightmap could allow for better etching consistency IF high precision is required. If that doesn’t matter, cool.
In the low-end space where I play, and I think well into the mid-range, the engraver/cutter is on a 2d gantry, basically a Core-XY 3D printer with no Z axis. I focus manually with thumbscrews and a shim. 3-axis and even 5-axis lasers exist, but I think most of them are industrial class.
So this is a variation on dye sublimation, one of the main ways legends are printed onto single-color keycaps. The process is basically your second idea and exactly as @Uranium_Green says.
This should cause the heat-activated ink to integrate more or less permanently to the polyester-based PBT plastic. Then I clean off the unlasered ink with isopropyl alcohol and/or acetone. The zapped ink doesn’t fade at all, though as you can see it’s not super vibrant.
The sweet spot to do this without charring or melting the keycap is pretty small, though though there’s probably another configuration where you use higher power and quicker movement. There might also be one at even lower power and longer time. I’d seen several people try it, but with weird projects on cheap lasers you’ve typically got to find your own settings. Also, don’t laser ABS; very bad idea.
Awesome, thank you! I could have Googled this, but it is always awesome to get information from someone who can give a better summary.
Since you are closer to the laser etching/cutting aspects than I am (I have a traditional hobby CNC machine and do a ton of 3D printing), I am curious if hight mapping has been integrated into laser etching yet. The reason I ask, is that when I cut fine pitch PCBs, I need to be at very specific depths of cut, usually within 0.1mm or so when precision is required.
Working with small curved surfaces could be problematic for maintaining the correct laser focal point? Maybe? Possibly? Even applying a generic hightmap could allow for better etching consistency IF high precision is required. If that doesn’t matter, cool.
In the low-end space where I play, and I think well into the mid-range, the engraver/cutter is on a 2d gantry, basically a Core-XY 3D printer with no Z axis. I focus manually with thumbscrews and a shim. 3-axis and even 5-axis lasers exist, but I think most of them are industrial class.