Warping on Flat Piece

Support & Troubleshooting
1

Hello,

I have printed a flat piece on a form 2 using white v4. Settings were set to lowest resolution. Parts printed, IPA bath 1 for 10 minutes, IPA bath 2 for another 10 minutes. Air dry until parts are dry then placed in curing oven for 1 hour.

Parts initially come out great and flat. One week later they are severely warped. These are functional prototypes so as soon as the parts become warped the prototype no longer works.

Any advice?

20181029_115240
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Thanks!

2

You can heat these in a oven on a fat cookie sheet at 250f for about a half hour. You’ll need to experiment on that. Moister evaporation does this and is common with both 3D printed and cast resin parts.
DON’T use the cookie sheet for baking afterwards.

1 Like
3

Do you mean heat them to unwarp them? Thanks

4

Yes, as bending them will introduce stress and they most likely will crack. You can do a search of “how to straighten bent resin castings” and see the results.

5

Do you know the root cause though so I can squash the problem before it even starts? Thanks

6

Even to make a educated guess, we have to know how you printed/cured it: Did you use supports, or print it directly on the build platform? Did you orient the model yourself, or did you use the PreForm auto functions? Did you leave the supports on for washing/curing?

7

I have a bunch of ruined prints caused by this. I find that post curing with heat longer than I used to really helps. Also making sure the parts are bone dry before putting them in my cure chamber. Maybe I’m crazy but I post cure for 12 to 24 hours in my UV led chamber. Perhaps leave them in the ISO for a shorter time as well. You really only need 5 mins or so per bath then I use compressed air to dry them off.

8

When I have a thin piece that I do not want to warp, I don’t “cook” it at all. I do the minimal amount of time in the Form Clean (depending how dirty the IPA is) take off the support structure and that’s it. However our prints are rarely functional but usually only for aesthetic evaluation on occasion they are used for snap fit evaluation and I follow similar for thin parts in those situations too.

9

Thanks for all the replies…here is exactly my process…

  1. Use Preform to orient parts. I allow the software to auto-orient until supports are not on my cosmetic surfaces. I never build directly on the build plate, always have a raft.
  2. I use 0.5mm point size 0.8mm density, white v4, 0.1mm layers
  3. Parts are soaked in IPA bath_A for 10 minutes then bath_B for 10 minutes with supports left on. 99% IPA.
  4. I set the parts in front of a fan for 5 minutes to help evaporate all the IPA, I make sure parts are dry before putting it into UV oven.
  5. I cure the parts in the UV oven with supports left on for 30 minutes on a spinning plate, manually rotate the parts to expose lesser exposed areas then bake for another 30 minutes.

Parts come out fine at first. Its only after a few days do they start warping. I do not have a form cure or form wash. My UV oven is as suggest by formlabs years ago seen here:

I’ve been using the form 2 for a few years now and only recently have I seen the warping get this bad. Maybe the last two software updates on preform. I am not ruling out that it could be my process though.

Just looking for insight on what to try to avoid this.

Thanks again

10

Any other tips? Thanks all

11

Attach a flat metal plate to your print, fix it with something to the plate. And put it into the oven. We had very good results, putting dental SG plate into the autoclave at 121°C, 1bar, 1hour. Let it cool down slowly remove the metal plate.

12

IPA warps and distorts the parts, longer you wash the part in ipa the worse it will get.

13

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