Print not fitting to dimension - any hints?

[drayson 75]

Hi all,

recently I printed a typical 25x25x25 mm test cube BUT....

it has only 24.73x24.75x24.83

I know, this is shrinkage (hopefully) but is there any way to anticipate it?

factor in cura?

setting of steps?

Has anybody deeper knowledge?

Any hints are appreciated!!

Thanks

drayson

 

[Daid 306]

Best way to compensate for it is in the 3D model. Shrinkage is a bit unpredictable and depends on the shape of the model. If you need submm accuracy you usually need to tune your model a bit. Just you need to tune an injection mold.

 

[drayson 75]

Hi Daid!

Thank you for reply!

Understud - depending on shape, geometry and "heat flow" the shrinkage of a particular part of the model is different to anoter part of the same model - so can not be considered via just a scaling factor in cura.

So best idea would be to print it once, measure it on several points, calculate the deviation, adjust the model itself by the calculated factors and print it a second time with hopefully fitting dimensions...

Right?

 

[Daid 306]

Yes, that usually is the method. There are some general rules that usually work. Like 3mm screw holes, if you want lose 3mm screws in there you use 3.2mm holes, 3mm holes for "screw them in" and 2.8mm for "need to use threading tools"

Generally "parts that need to fit together" you keep 0.2mm clearance.

But these rules do not always work.

 

[drayson 75]

Got it... lot of tweaking as usual :-)

Thanks for your assistance !

 

[gr5 2,234]

I often print only 3 or 4 layers and abort the print. Then measure the actual size and go back to the cad and adjust.

 

[bret 0]

That is a great idea gr5. I think I will start doing that more often.