So, we have our exposure times sorted out. We’re golden now, right? Time to hit print!
Well, no. It’s still not that easy.
Resin printers have a build plate that pushes close to the transparent membrane in the bottom of the resin tank, the UV sets a layer onto the build plate, then the build plate actually mechanically raises itself up pulling the set resin off the membrane, allowing fresh liquid resin to rush in, then moves down for the next layer of resin to attach to the last layer as the UV light sets it.
That means – more variables! And you thought you had it cracked!
We can actually set the speed that the base plate raises the resin print off the FEP release plastic. And oddly, this is one area where I believe (thanks to the wisdom of many much more experienced 3d printers) that the default values you are given (for the Elegoo Mars Pro at least) are basically totally wrong.
If you set the lift values to go very slowly (40mm/min) then then plate very gently retracts, and this tends to work very well, especially for detailed prints. You can go the other way with “Vroom Speed”, and set it to around 240mm/min and then the plate goes quite quickly with a comparatively sharp yank.
The default values of 90 or 100mm/min are actually terrible. They go fast enough to put force onto the build, but slow enough to extend out the period that force is applied for. Going as fast as possible gets the pull off the plate done quickly. Going as gently as possibly minimises the stresses. This middle of the road setting? It’s the worst one to pull minis or parts of supports, or have supports not reach key pieces.
I generally use Vroom speeds for 0.05mm layer standard quality prints, and very slow 40mm/min speeds for 0.03mm layer high quality prints, and I find that works well for me.
This is something I haven’t found very well documented online, and came across chatting in 3D printing chats with people who do this professionally. It makes sense to me and has definitely given me more reliable and better prints.
Learning curve, eh?