Casting parts in silicone is great, and 3D printing in resin is fantastic for making clean shapes, so it’s natural for an enterprising hacker to want to put the two together: 3D print the mold, pour in the silicone, receive parts! But silicone’s curing process can be inhibited by impurities. What’s cure inhibition? It’s a gross mess as shown in the image above, that’s what it is. Sadly, SLA-printed resin molds are notorious for causing exactly that. What’s a hacker to do?
Firstly: there are tin-cure and platinum-cure silicones, and for the most part tin-cure silicone works just fine in resin-printed molds. Platinum-cure silicones have better properties, but are much more susceptible to cure inhibition. Most workarounds rely on adding some kind of barrier coating to molds, but [Jan Mrázek] has a cheap and scalable method of avoiding this issue that we haven’t seen before.
A small number of the test pieces used to narrow down a working process. These pieces have loads of flat sides and corners. Many potential solutions worked only for flat mold surfaces, leaving corners problematic.
[Jan] goes into a lot of great detail about this issue and his results, but here’s the short version: after carefully cleaning the resin printed mold to ensure absolutely no uncured resin is left on the surface, he submerges the print in water. The print (sitting in the water bath) is exposed to external UV curing for 30 minutes, followed by a 6 hour soak in the water. After this, the water is changed and the process repeated. That seems to be all that is needed to end up ..
Support the originator by clicking the read the rest link below.
