Stephen Attaway wrote:The specific gravity is a function of how well the resin is cured. I measured heat cured resin and found a specific gravity of 1.191. Freshly printed parts on my projector using 1:1 mix with 30 micro xyz settings had a specific gravity of 1.178. The only difference between the red and cherry resin is the amount of optical absorber in the resin. This is a small percentage, so the red and cherry should be close to the 1:1 mix.
The parts are plastic-like with the ability of a 1.5 mm round wire to flex more than 90 degrees with a 5 mm radius bend. The parts will spring back after bending. The material is quite tough.
When over-cured parts become more glassy and may crack along growth lines.
Could you be more specific regarding strength. Strength means different things for different applications. Tensile strength, compressive strength, and shear strength can all be measured for the correct application. Yield strength is often used for metals to indicate the onset of inelastic behavior. I don't think yield strength is very applicable for the resin. It generally breaks (with a snap) before it takes an inelastic set. As with most polymers, the properties will often be temperature dependent.
I have printed 500 micron by 1000 micron vertical prongs with lengths of 5+ mm without problems. Printed parts will bounce quite nicely when dropped.
Can you give us a better idea of the lab test you plan?
Thanks for your reply, it's really helps.
As our lab text, we want to have a project (500 microns) that has both high stiffness and strength. So, do you ever have any text data to measure this part? Like to say, just the simple compression text, do you have some data about the compression strength and strain. If you can give me something about this, It give us a specific concept about how this 500 microns' project will be.
Thanks a lot.