3D Printing Forum

Hi everyone. I'm wondering if anyone can help me determine what might be going on here. It's oddly much more difficult to see in photos, but nonetheless: I seem to be having an issue where there are dimensional inaccuracies in certain areas of prints when the exposed surface area increases. Hopefully you can see that the edge of this drawer pull isn't straight.

Details:
Duplicator 7
NanoDLP
Esun Hard-Tough Resin
Printed twice. Once with moderate settings, again with extremely conservative/slow settings.

Theories tested and not at fault due to test #2:
- not enough reflow time (wait after lift). Thought this was it given the viscosity of the Resin.
- not enough wait before exposure (not drastically changed though)
- lift too fast causing supports to move.

Theories:
- not enough supports for the uppers section. Though there seems to be a lot already!
- resin has a Young's modulus or 1350MPa, so is a little flexible (particularly during print). Perhaps they move during lift and don't return? Though I've slowed this down so much that it doesn't seem to be the case.
- overcure? I do have pixel dimming enable to hopefully help with this.
- as mentioned, there is some correlation between area and this phenomenon. In this print, it happens in the area where the surface area increases as it goes from Just not sure what exactly causes it in combination with that.
- trying a different resin as a test

Any ideas or tests would be extremely helpful. Thanks everyone.

Hi.
Have you tried printing in the other way around, turn it through 180°.
You could also try printing it at 45°.
Also look at supports, do you think it needs more?
These are just my suggestion. They may lead to a solution.
Lez

Hi. Thanks for the reply. In the meantime, I've definitely tried many things. Many of your great suggestions too.
- unfortunately I can't flip it around 180 since that leaves the important areas facing the bed and would result in an unpleasant surface finish
- I did try all sorts of angles which was interesting. What was revealing was that the issues followed the transition where it goes from two small areas to two large areas. So it's definitely something to do with that.
- I also did one that I supported to a nearly unusable degree. Just to rule that out. Though it still might be related to supports/print moving.

Thanks Lez. I really appreciate the reply. I'm definitely stuck at this point.

It sounds like a suction issue. As the printer is printing the biggest area it is pulling the edges as it releases from the build plate.
You could try thicker supports around the area that is distorting.
Did you also try laying it on it's side, this should give you a move uniform part.

At times resin printing seems like a black art.

Lez

Sorry I meant to say: as it releases from the FEP, not build plate.