Fitting parts - steel and sls

#1

Just wondering about fitting parts with steel.
If an object has a 20mm diameter hole, what diameter should a peg be to fit in it with the least play but still easy to remove from the hole?
And the same for sls.
Thank you

#2

Hello,

For steel this is hard to say because as the production of your model involves a thermal step, shrinkage is something you should take into account and this may have also an influence on the peg.

Clearance should be at least .8mm, but the shrinkage is different between small or big parts. Please be aware that we do not guarantee the dimensional accuracy of the parts printed in steel, but small adjustments to the final printed model can be made by yourself using mechanical methods. Minor deviations in size are acceptable and sometimes deformation may occur. This material is not recommended for technical and functional parts requiring high precision or for fine jewelry with delicate details and parts with walls under 1 mm thickness. Please read also https://i.materialise.com/en/3d-printing-materials/steel/design-guide#anchorShrinkageCompensationandDimensionalAccuracy11

The answer for SLS is much easier and can be found also in the design guide at https://i.materialise.com/en/3d-printing-materials/polyamide/design-guide#anchorTheRightSpacebetweenYourMovingParts4
Kind regards Lizy

1 Like
#3

So just to understand the math of clearance.
Would the peg be 19.2mm that fits into a 20mm hole?
Or would it be 18.6 mm in diameter.
Thanks

#4

Hello, as I said before it’s impossible to advise you with exact numbers because we always have this shrinkage compensation of 2 to 3%. Our accuracy is up to ± 1% (after the shrinkage compensation). So, if you order 19,2 mm, this peg should fit, but we can’t guarantee that it will be exact 19,2 mm and as long as the peg is within the shrinkage and accuracy limits it will be considered as a good part. Kind regards Lizy

1 Like
#5

Hi, if hole diameter is critical it is best to print an under sized piolet hole and thin drill the hole to size this will give you the precision you need.

Ford

1 Like