Getting inside and outside print dimensions accurate
Hi People.
I'm working on getting a printer to produce dimensionally accurate prints. So far I have adjusted skew and axis scaling in the firmware, and things were looking pretty good, but my latest test print suggests I still have a way to go.
I had a look to see if other have run into this problem, but while I'm getting a lot of posts about "hole sizes too small while outside dimensions correct", that's a different issue to what I'm facing.
Essentially my outside dimensions are good, but my inside dimensions are not. Refer the test print I made, with beveled edges top and bottom, sized so as to have both "50mm" and "100mm" inside and outside measurements. (not sure why the image is cropped, cutting off the top of the print, but suffice to say the print is just a bunch of squares in the right places)
So the "50mm" inside averages 49.76 and the outside averages 50.42, a difference of 0.66mm.
The "100mm" inside averages 99.50 and the outside averages 99.94, a difference of 0.44mm.
I'm wondering, is there a way to correct for this in PrusaSlicer? I was wondering about reducing the extrusion multiplier, but I don't want to create problems elsewhere.
I see there is Print Settings->Slicing->XY Size Compensation. But I'm wondering if this is just the same as scaling the print in the slicer before printing, or if it behaves differently to that. Just scaling the print will not fix this.
I think what I need to do is somehow tell the slicer that the extrusions are wider than it actually thinks they are, so it can make the outside smaller, the inside bigger and I can readjust my scaling so everything is bang on. Or maybe I'm wrong too.
The nozzle is 0.8mm and the layer height is 0.3mm. External perimeter extrusion width is set to 0.9mm.
Here is a look at the underside of the print. It looks OK to me.
