Month: August 2016

All holes in my parts become 0,5mm smaller than designed. Why?

I have printed a calibration cube before, which was exactly 20x20mm, with some negligible margin like 0,04 or 0,08. I just checked my latest printed part and the width is nearly perfect. It’s designed to be 35mm wide, and it measures exactly 35,00 (with +/- 0,05 error, depending how I hold the micrometer I guess).But this latest part has holes, e.g. 4mm diameter, and they turn out to be much smaller. E.g. 4mm becomes 3,5mm, 16mm becomes 15,5 and 7,3mm becomes 6,8mm. So when I design parts, I always seem to have to add up 0,5mm and maybe another 0,1 so the screws go in easily. It seems to be the same size of my nozzle, which is also 0,5mm, but I have doubts it has something to do with it. Even 3mm holes become 2,5mm!This happens whether I use Cura or Slic3r, and I don’t know how I can fix this. It must be somewhere in the slicer settings, or the printer settings. But where? Adding 0,5mm to any circle inside the part is a solution (with 0,1 or 0,2 extra for some space so the screws get easier through), but this week I downloaded a bowden carriage part and it had the same error of 0,5mm. Which makes me believe it’s in the settings.EDIT/UPDATE: So it seems that the wall goes over the outline of the hole, and since my nozzle is 0,5mm, 0,25mm end up outside the hole and 0,25mm inside the hole, making up for the 0,5mm smaller holes. A simple algorythm that’s been created by Bowyer would have solved the issue, then users started to complain about too big holes and it got removed from Slic3r again. So far for the development in 3d printing… http://ift.tt/2azjRDl