I always wanted to start a project for making 3d prototypes with my laser in layers similar to how the legacy Candyfab project did, but never got around to it. With the recent Candyfab news , and the relative success of my Laser Cooked Bacon project, my curiosity got the better of me and I wanted to see what would happen.
I did some research and I wasn't able to find anyone that had melted sugar with a laser, there was some posts on the Candyfab forums, some seemed to think it was possible, and some did not.
So I fired up my laser and got a small dish of standard granulated sugar, all I had to do was fire the laser and see what would happen.
Success! At 60% power (of a 40w co2 laser) and 5cm a second speed, my test text melted right into the sugar as I expected.
The sugar sagged a bit and the melted sugar kind of sank into the sugar below. It was also about 3mm thick front to back, I used my trusty Laser-Cut Caliper to measure.
The sugar stuck to the edges of the text a bit blurring out the outline. I also tried cleaning up the letters with a bit of water, but without just the right technique the sugar dissolved very quickly, but it did help some with the edges. That technique is probably impractical with this size of construction.
The second test was at 80% power and 15cm a second speed and was 75x75mm in size. The resulting construction was much thinner, about 1.5mm and fairly fragile. If I were to make a 3d object with layers, I would use a power lever similar to this. The sugar was only slightly discolored, and there was very little sagging. The construction ended up breaking when I was measuring the thickness.
The third test was at 80% power and 5cm a second speed, this object is 50x50mm. The result was very solid and durable for sugar, but had quite a bit of sag and was yellowish on top. If I were trying to rapidly crank out some custom sugar treats I'd go with this power and speed.
Since the sugar never comes into physical contact with anything else, it should be safe to eat. I couldn't resist and sampled a bit of the last test, and it tastes exactly like caramelized sugar, no big surprise. If the sugar was mixed with another powdered flavoring (like cinnamon or coco) you could get some more interesting (tasty) results.
I may make some custom sugar treats for my next house party, they might go good on top of a cupcake or in a drink.
Another interesting side-note, when hitting the sugar with the laser, the sugar flared up a bit with a light orange flame, but with no smoke. I'm not exactly sure why that is, but it seems relatively harmless.
Eventually when I rebuild my laser into a larger frame, I will try to make some previsions for making 3d objects in sugar with a special sugar tray and layer leveling device.