I’m struggling to print a part with silicone 40A on a Form3 and need some help.
It’s essentially a hollow cylinder with some internal features at either end.
The outside needs to be clear of supports as far as humanly possible because of the use case. But I’ve put significantly more support on the inside of the cylinder than PreForm puts on automatically.
So far I’m just getting failure after failure. It’s not a cup but it gets pullet apart as it prints.
Any suggestions?
Help!
Hi Kiml,
Can you send some photos of the print failure and also attach the .form file so we can take a look at what’s happening?
Photos of the first (left) and most recent attempts are attached. I’m hesitant to share the .form file on the forum, is there an email or some other way I can send it to you?
Pretty sure that he first attempt printed the whole way through, but then the “bottom” (top in PreForm) part broke off and dropped into the resin vat while the build surface was hanging to allow resin to drain.
I stopped the most recent attempt part way through because a tear developed not far from the build surface (you can see the big bulgy bit, where the tear was, although it stuck itself back together during curing). There wasn’t a tear in that spot from the beginning, but it seems to have opened up as the print got further on and that weakened portion got stretched with each layer that had to release from the build plate.
The three or so attempts in between mostly failed in same way as the most recent one, but I didn’t cure them. I’ve tried adding in some designed support, but the main CAD person is on an extended holiday so I have limited functionality.
Hi Kiml,
Thanks for sharing the details and photos! Silicone 40A can be tricky, especially for parts that need minimal external supports. From what you’ve described, it sounds like a combination of internal tearing, cupping, and layer release issues might be causing the failures. Here are some things that could be key to improving your print success.
It looks like you have cupping relief holes, since Silicone 40A is very viscous, you should make those a little bigger. The high viscosity might still be creating negative pressure with each layer peel inside your cylinder. With that change, I’m curious to see how that would turn out.
If that still doesn’t work, for Silicone 40A, we would recommend exploring custom tearaway supports, which allow you to better support the part from the inside, reduce stress during printing, and minimize marks on critical surfaces. Our article Design Guidelines and Tearaway Supports for Silicone 40A Resin has examples, tips, and a video to walk you through the process.
Feel free to share more details or reach out with updates on your progress! Looking forward to seeing how it turns out!
Much better results with the bigger relief holes.
I accidentally put a hole right in the middle of one of the walls, but on the plus side that gives me a another try to reduce the horizontal ridges a little.
Any tips for making the outside surface more consistent?
Great to hear! It’ll be tough to get a perfect surface with such a soft elastomer. If your application allows for it, you can try thickening up the walls a bit.
It could help to print the part with a slight tilt to reduce the risk of pulling apart. Make sure your internal support is firm but not too dense—silicone 40A needs some room to flex.
