BinderJet x60 Shrinkage, Bowing Issues

[Reimz]

Has anyone experienced bowing/shrinkage/warping of objects printed using a ProJet 660 printer or anything similar?
This is mostly noticeable when printing large flat objects. The corners seem to either sink into the powder bed or the centre shrinks when cooling maybe?
It can be up to 3-4mm over the length of the print bed (380mm) and in all directions but mainly along the horizontal plane. There is some slight shrinkage in the other planes too but not as noticeable.
I have tried turning the heater off after the printing cycle to see if that helps regulate the temperature in the build chamber but it hasn't made any difference.

[CSMonkey]

Projet 660 if I remember is the new name for the ZCorp plaster machine.

Any distortion has nothing to do with heat, that's not how this process works. It's the mass of the binder infused geometry sinking into the powder bed. There was a function to create supports to stop this happening on the machines I had, or simply print some support pillars that don't quite touch the underside of the model. This will stop the parts shifting.

Shrinking happens as the parts dry in their green state and can be compensated for. You need to use the on board heating to dry the part to make it removable or you risk breaking the parts.

Hope that helps,

Rich

[Reimz]

Thanks for the advice Rich!
I can see how the models would sink in the powder so that does make sense. Ours only seem to sink in the corners of larger square builds but also some models of scanned figurines there heads tend to drop out of shape when printed on their side and also some round objects come out oblong!

We have also had issues with thin builds that are printed at the top of the build chamber curling up and breaking through the top clean surface of the last few layers of powder. We haven't had a problem with parts breaking with the heater off, but we do leave most of our builds overnight before pulling them out the next day so that would let them cure well enough to be handled.