[jan Mr รก zek] is committed to making resin 3D printing more accurate, practical and less prone to failure. Let’s start with his recent article on preventing resin shrinkage.
When you want a part with an inner diameter of 35mm, you may have a good reason. When you draw a circle in CAD software, you want a circle to appear in the real world. Resin shrinkage may cause problems in both schemes. [jan] identified three culprits: resin extrusion, resin shrinkage and exposed bleeding. These three factors will be superimposed together in unexpected ways, so when you print alone, you will get a small reference cube, but when you print as a group, you will get a large reference cube. [jan]’s article comes with a test piece that can help you diagnose what happened.
Then things get complicated! Exposure bleeding depends on the printer and exposure, as well as the color of the resin and UV opacity. The shrinkage obviously depends on the chemical properties of the resin, but it also takes several days to reach the final state of complete curing of the printed matter. Of course, the curing rate also depends on the temperature. [jan] has just started to record all variables, but you can print out his test pieces or do your own work – because of the differences between resins, you may have to do this anyway.
When you are in this rabbit hole, look at [jan]’s post on stickiness and elephant feet. If you are troubled by the strange first layer, this is a huge resource. There is a simple lesson to take home: wait longer at the beginning to let the resin flow in.
Whether you are engaged in resin printing or experienced professionals, we have a lot of interesting resources. From this article about choosing the right resin to this article about whether to use resin or FDM, you have a lot to read. It’s not even mentioned that he chatted with Andrew sink’s gooey hack last fall, where he and the audience provided a lot of wisdom.