scaling issue with internal \ external dimentions

[33phil9]

Hi! I need help with simplify3d scaling… I am trying to print figure as below… In the model external size (marked with red) is 29.214mm and internal circle is 6.4 mm.

Once printed in 100% scale external is 28.9 and internal is 5.0 ☹ once I adjust scale to 101,08 external prints with tiny difference, but internal is still very small. To print internal in right size I need to use 128% scale ☹ but it drives external size far away…

Which settings should I consider to be changed?
Many thanks!

[wirlybird]

Small holes are going to do this. No real way around it. Just the nature of the process.
If you can't enlarge them a bit in the drawing for the model then drilling/reaming them out is the only other real choice.

As far as the outer dimension being off it isn't much which can also be anticipated but could be that you are under extruding some or it is a mechanical issue.

You might see about doing some calibrations using a 20mm calibration cube. Lots of articles about it around. May help.

What printer and material?

[33phil9]

cube prints fine... external diameters are good. it is something with slicer and holes. i guess it is a buggy algorithm....

with test i have figured out that horizontal compensation -0.25 mm worked with my 101,08 scale.. however that ratio brought down external size in my particular case i can live with that, but it is very and very strange...

[MicroVoxel]

Try playing with extrusion multipliers and horizontal size compensation. I find this model to be very helpful.