Hello everyone. I am trying to print a solid cylindrical (OD - 50mm, ID - 15mm, H - 45mm) using the elastic resin. I am going to use it as a roller for a robot. Therefore, my primary requirement is smooth and even surface. For the first print, I printed it vertical with no support touch points on the circular surface. However, the print was distorted in XY plane (A) (pic inserted below). Thereafter, I printed a 1/4 size model at 25deg (B), 45 deg (C) and 90 deg (D) (pic inserted). I was satisfied with the 45 deg model and planning to print full scale model.
I am not sure about the support sizing and density. I have been using 0.6mm-0.85mm for my prints. And I would love to know if anyone has attempted this before and share their positive results.
Also, for post processing, what would be the most efficient way to remove the support material without affecting the surface finish.
For the first print, I printed it vertical with no support touch points on the circular surface. However, the print was distorted in XY plane (A) (pic inserted below).
Just to clarify, did you print completely unsupported, directly on the build platform, or just vertically oriented but on supports? It looks like it was directly on the build platform but I want to be sure.
I really like working with Elastic resin, but it has a lot of quirks and this application may not be the best for it. It’s great to be able to print things like this directly, but in this case, for simple cylindrical geometries, you might have an easier time printing a mold in a general-purpose resin and casting a silicone or polyurethane rubber roller. It would be more steps from your design to your finished part, but you might get. better, more consistent results.
That being said, it’s not unreasonable to try to print this. Assuming this is a cylinder where the 15mm ID hole goes all the way through, the first thing I would try is another print directly on the build platform, but with the bottom vented to eliminate cupping and potential pressure blow-out issues. I would subtract a vent channel like this: vented-cylindrical-roller-for-elastic.stl (102.4 KB)
and see if that reduced the distortion when printing it. It might not help, but I think it would be worth a shot.
Unfortunately, I don’t have much advice for your support sizing and density, but my opinion would be to try a smaller support size and higher support density first. It’s difficult to get a good surface finish after removing supports in Elastic, but there are some things that some people have success with: careful regular sanding and buffing with a lot of patience, freezing the part first and then sanding it to make it harder and more sand-able, and trickiest of all, re-coating the support marks with some liquid resin (possibly thinned) and then curing that with sunlight or a Form Cure.
Hopefully some other folks will chime in with additional ideas.
My last rings prints from elastic resin show no issue while printing with supports and not direct on the build platform. I’ve posted it in other thread, here are the main info for your problem:
“I’ve printed 3 rings 10mm height , 1.5mm wall thickness with diameter of 19.82mm, 20.76mm, 33.77mm”
Regard to the surface finish of the supports, for this kind of models, i’m printing it a bit longer and cut the edge with sharp knife such as Scalpel (surgeon knife).
Thank you reaching out, your answer was really helpful.
Answering you questions -
I didn’t build directly on the platform, it was supported on a raft of 2 mm thickness.
Some comments/followups regarding the problem -
You’re absolutely right to point out that I could get more consistent result with silicone molding. However, in this particular scenario, 3D printing is my only option.
Since this material is elastic, I am scared that sanding directly might peel off a chunk of material and therefore, waste the part. Would you recommend that I freeze the part and then sand it?
I am also thinking that since the hardness of the material is higher than what I expect, I would modify the design slightly (add holes in the solid part) so that it could compress and give me a softer feedback.
It is a little bit wider on the top edge, this is happens to every print with elastic that i’m using. it is for the last 2-3 mm of the part and giving me some assistance while i’m placing this ring on a shaft. If you need something completely straight by definition, just print it longer and cut both edges.
If i’m looking on it its parallel from both side and not distorted to the side as your first picture.
Give it a try with supports, the flexibility giving it some space to return to its place from layer to layer.
The tolerance is quite larger then required, I find it to be 4-5% larger then set.
