Warping - not talking about space flight

Having gone through my first liter of resin, I am battling a problem of keeping parts flat.

I have printed the same part - about 30mm x 20mm at about 1mm thick several times. I’m having trouble keeping the surface flat. Once I clean off the alcohol, it seems very flat and nice and smooth. However, at some point during the curing process - either by UV lamp or outside sun, doesn’t matter - the surfaces warp. It happens with both clear and white.

Is there any difference to build orientation that may cause this?

Any recommendations on how I can get them flat again and they stay flat?



In my experience, limited to non-Formlabs resin, it’s the fast curing (and associated heating) that causes warping. Rinsing the part well (IPA, then water, then warm water, then hot water, then quick IPA rinse again) and curing slowly should reduce the warpage.

I have had to stop producing parts for clients with completely flat surfaces and no additional support (web or hollow frame) as I could not prevent the warping. In my experience curved and organis objects print much better than flat ones. In my opinion it isn’t just an effect of the curing process but also down to stress built into the print during the peel process - I often noted that the direction of warping corresponded to the direction of the peel.

I really like both suggests. Thanks both of you.

I’m going to print the same parts once again. This time, one of them in the same orientation as before, but will be using Ante’s suggestion (makes good sense to me).
The other part will be 45 degrees rotated about the peel axis as this too makes logical sense to me.
I’ll post my results later for all to see.

Thanks again

I’m curious. How’d it go?

I gave up. I still can’t get a flat part direct from printing. If I need a flat surface I increase the size then print it. Then, using files, sand paper, and sometime my mini mill I shave it down to the required dimension. It’s a pain, but the machine just can’t make thin flat parts.
To tell the truth, I’ve had the machine just about 2 1/2 yrs and have not been very impressed with its results. I don’t use it very much any more.

Avoid heat–hot water will warp it and it can warp from the heat of the sun as well.
Arrange the supports so that it has a good structure to keep the shape while it cures and don’t remove the supports until you need to since that will help keep the shape.
Besides that, making it thicker and sanding it down is the other way to get them flat.

have you tried putting a weight on top while its warm and letting it cool?