Buld a cheap but reliable SLA LCD printer
Posted: Sat Apr 01, 2017 3:55 am
I plan to build a low cost but reliable SLA printer. My goal is a resolution of 200 micrometers on all axis.
My idea is to base it on a 5 inches raspberry screen (25 €) to keep the cost low.
I want to use a top-down configuration as it seems more reliable (that is my first SLA printer).
It will use daylight resin, for example the one of photocentric. Eventually I may test salt water with some resin floating on the top of it to not have to fill the whole tank with resin.
One of the problem is the XY precision: if the light does not go straight through the screen to the top of the resin, the picture projected on it may be blurred. To avoid this I plan to put the screen just 1 millimeter above the resin, and to have a unique blue LED of 10 watts 12 centimeters behind the screen. In that configuration the XY blur would be approximately of 100 micrometers.
I plan to use acrylic plates of a thickness of 3 millimeters. The tank would be 111x121x90 millimeters (XYZ).
The Z axis translation would be made using 4 M5 threaded rods, a belt and a stepper motor. It will not be very precise, but I want to keep the cost very low.
The screen would be separated from the resin by a thin transparent film to protect it from resin, even if it should never touch it.
I plan to use a 5 inches raspberry screen (800x480), so an XY resolution of 125 micrometers.
The blue power led would be a basic 10 watts. I hope it will be enough.
I will use a raspberry to drive all the stuff, with nanodlp software.
I wonder if I should set the platform goes down and then up between each layer to help the resin goes everywhere ? Or if simply goes down by the layer height between each layer and wait a bit is enough. My fear is that if it goes to deep, some resin may touch the screen on the way up …
I plan to use 200 micrometers height, does it seems realistic to you ?
Do you have any advice ?