Also, a picture is worth a thousand words. This initial test is what leads me to continue dehydrating parts. Again, I need to document some more in depth testing in a video, but that will take a lot of time that I don’t have right now.
From right to left:
- Dried with compressed air then post cured with standard protocol
- Air dried for 3 hours
- Dehydrated for 3 hours at ~35-40C
The support structures here are actually the perfect shape and geometry for exaggerating the effects that otherwise would be less noticeable on thicker parts.
Another interesting thing here is that all three of these parts looked identical before placing them in the curing oven. It wasn’t until heat + UV that warping occurred. Probably due to some kind of internal stresses introduced in this step.
The context here is that I was actually helping the materials team test warping on a previous part that I had issues with several years ago but upon re-printing last year noticed it warped less. We chalked it up to potential improvements in print settings, but I was curious because I knew that my process around drying had changed over the years so I ran this test.
I also was never really satisfied with how random warping on parts seemed, but over the years started to see a correlation with warp during rush jobs where I didn’t have time to air dry for a prolonged period of time versus other jobs where I had the time to leave parts out.
This also ties together very strongly with dimensional accuracy issues I’ve observed with Flexible and Elastic resin - which are also very much caused by IPA absorption (see link below). In these extreme cases, you can see how significant IPA drying can be on swelling of these elastomer-like materials so I believe that we can, with some confidence, also assume IPA is absorbed and trapped in rigid materials as well, causing swell, stresses and warping during post cure (as well as dimensional accuracy issues but at a much smaller scale than we see on flexibles).
I guess I can at least regurgitate this up in a blog post sometime in the next week 