A drawing against warping

Recently I had some issues with warping when printing the upper half of a (dummy) motor block. The print sticks well onto the building board, but after removing the print and its support the front and the rear end of the shell bend up by a half respectively one and a half milimeter. Print with z-ultra, 0,9mm, side covers. Since I need two shells - upper and lower - to place the real engine within, I tried a solution that normally a fancy software might calculate - I bent the original drawing to get straight results.

Thats the object I want to have:

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Motorblock.jpg

And thats what has to be printed:

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Motorblock 1.jpg

In Rhino its easy to bend objects, I started with the values the first print was deformed, i.e. one milimeter and one and a half. Second print showed I overdid it, now front and rear end were hanging down. For the third print I took half of the correction, and - strike :) the bottom was flat.

Yes this can be an extensive solution and needs some trial and error. But if you need several identical parts and you need them right I think its worth a try.

cheers

Andi

Cheers for this Andi,

Great for a surface that wont be seen.

I think someone on here recommended pausing the print after the first few layers are printed allowing to cool and then restarting. Need to speak to him actually, pick his brains/intuition.

Cheers

Andy

Thanks, I guess this particular problem exists only with half-shells. The tensions of the material are retained as long as the print sticks on the raft and the building platform, but as soon as all that and the inner support of the half-shell is removed they become effectiv.

Pausing the print might be another solution. But since the drawing is adapted now.... ;)

cheers

Andi

Did you try a ABS juice?

No, since the print sticks well to the platform.

Could moisture have an effect on the z-ultra?  The workshop is not continously heated, so the humidity rises on rainy days.

regards

Andi