I’d like to get users thoughts on post cure warp. It often rears its unpredictable ugly head. Countless hours and material have been lost because of post cure warp. It is causing me to think my purchase for a Form 3 was a mistake. Here is my latest example:
13 duplicate parts. The part is roughly rectangular 2.9” long, 0.3” wide, a middle thickness of 0.175” with end thicknesses of 0.118”. There is a gradual taper from thick to thin regions. The material is standard clear. The layer thickness is 0.1mm. Build orientation approximately 10o to 12o from build platform. The support settings are 0.85 density, 0.4 touchpoint size, and full raft. The only change from default support settings is density, reduced from 1.0 to 0.85.
All pieces cured with all supports and raft attached. 2 pieces were Form cured at 50 C for 10 minutes. The default Form cure setting for clear is 60 C for 15 minutes. Both of these pieces were grotesquely and unacceptably warped in a localized region. 11 pieces sun cured for 1 hour, at 42o latitude, on July 26th, 8am approximate 75 F ambient temperature, direct sunlight, placed in aluminum foil pan on an surrounded by black asphalt and a light brown brick wall. Of these 11 pieces, 4 to 5 were acceptable, the other 6 to 7 grotesquely and unacceptably warped in a localized region.
Assistance please. Thanks.
I am sorry to hear that you have been having problems with warping on your parts; I know first-hand how frustrating it can be to have warped parts ruin a lot of time and effort spent on printing them. Given that the parts are still warping even after lowering the heat and attempting a sun-cure alternative, I think that it’s possible that the very thin nature of the parts could be exacerbating the issue.
With all of that being said, I think the best way to ensure a proper resolution would be to reach out to our Support Team; they will be able to review any photos and .form files to see if there is a better orientation that could lessen warping, or maybe some alternative options for curing (for instance, completely turning off the heat when curing or maybe omitting this process entirely [Standard resins like Clear don’t actually need to be cured, but only to get the full listed material properties on our website]).
Please feel free to ask any follow-ups here, but I do believe that Support would be your best bet for a personalized solution. Take care!
I’ve kept detailed notes in Dashboard. I will those notes to compile a report and send it to support. But this will take some time. I have pictures of my latest problem parts, and I have pictures of other warp problems. Turning off heat when curing may be an option, but not curing is not an option, as the parts are too soft and sticky. Most of my parts have been gray standard or clear, and post cure warp seems to be more of a problem with the clear.
Again, I will compile a report, which will take some time.
It kinda depends on which resin you are using, but like @Corey_M said, try running the curing chamber without heat. I ran into issues like this as well initially which was very frustrating. Also are these mechanical parts you are trying to make or are the aesthetic models? Because if they are just for prototyping or show, there is not as much of a need to cure them with heat as that would be to get the full mechanical properties of the material.
Yes this issue is also the bane of my existence…until I started curing some parts without heat but it depends.
Thin geometries will warp more. Parts with supports removed will warp more. Parts that haven’t had adequate time to dry from IPA will warp more. Certain resins will warp more (eg. Tough 2000 vs Rigid 4K).
I’ve found that curing without heat but for at least 2X the time leads to acceptable parts if they don’t need full mechanical strength (has worked for almost all applications except a select few).
The IPA and the no heat 2X tips are very helpful. Because I’m often rushing, my parts often are not adequately dried, but I usually towel dry them in those circumstances. I can typically accept parts with less than full mechanical strength, but I cannot accept parts that are not cured. What was frustrating about my last sun cure is I doubt the temperature exceed 35 C, but apparently that was enough.
One thing to add is that the sun-cure would be a less consistent method of curing since certain areas will get more direct light exposure than others; unless you are moving your parts every couple of minutes (flip over, rotate 90º periodically, etc) then this inconsistent exposure could actually make the parts more prone to warping (depending on geometry).
As for the paper towel method for drying parts in a pinch, just be careful not to leave too many fibers on your part from the paper towel. Personally, I will either used canned air or use my air compressor to blast parts that need to dry in a hurry; the air compressor is a more practical method because you would run through canned air pretty quickly. Just be sure to have some sort of back-stop so you aren’t spraying resin-contaminated IPA all over the room!
Thanks for the sun cure tips and good idea re: compressed air.
Always happy to help! If the issues keep happening despite these tips, please do reach out to our Support team so we can take a closer look at the parts being printed so that we can assist further.
I have a “hot air rework station” for soldering work. It has adjustable temperature, from about 200F to something over 600F. I set it at the lowest temp and highest blower speed and use that to dry off IPA. At 200F, with the wand about 10" away from my hand, I can tolerate the airflow indefinitely, so it’s not really heating things up very much. But it does a really good job of getting the IPA cooked off quickly, especially when blowing air through the underside/support side of the print. A regular old hair blow dryer would work as well as long as you don’t get too close to the print and overheat it…
Thank you, Randy. That was helpful. I found that a hair dryer from a distance worked well for me.
Has anyone done 2 stage curing? That is, a first cure a part with no heat, then do a second cure with heat. I just did a test case and it worked well. After the first cure, the part didn’t feel to quite have the strength that I desired, so I removed it from the supports, then cured it again at 40 C for 10 minutes. I removed it from the supports because it has a flat surface that I placed directly on the turntable, so there was no risk that it could deform under gravity with heat.
I’ve definitely done some similar “alternative methods” for curing and that sounds like it could be a viable solution for your parts; not every part (especially thicker parts) is as prone to warping, so trying to find a personalized solution when you run into problematic parts is always a good idea. Please do keep us posted with how this method pans out!