internal hole size tester

thingiverse

Human: Make sure to turn OFF "extra perimeters if needed" or else you might have too many perimeters even when you dictate a single one. It shouldn't happen, but it did for me. I've always had trouble with internal vertical hole sizes and I'm fed up. I don't want to have to manually compensate either in slic3r or solidworks and my printer is pretty well calibrated so it shouldn't be off by ~0.5mm like it is. I set out to figure out what's going on. This problem is detailed in various forums: http://forums.reprap.org/read.php?263,129116 http://forums.reprap.org/read.php?263,134103 https://github.com/alexrj/Slic3r/issues/1588 http://hydraraptor.blogspot.com/2014/06/why-slicers-get-dimensions-wrong.html I've heard to use a single perimeter and that gets pretty good fidelity, but I find parts are weak or you have to use a higher infill to compensate. I've heard print external perimeters first and this should work in theory; it should push perimeters into the infill rather than internal hole interfaces, but in practice I've seen overfilling and just not had great quality. I would think it would be beneficial to eliminate the infill overlap So I made a short square 30x30x3 with a 3.5mm diameter hole and wanted to see if I can get it to the right size. I made 6 versions corresponding to Part0-5 with 0-4 corners cut respectively and two corners cut across from each other for part5 #6 Let that sink in, it's the most elegant solution for a simple test I did three sets of tests each giving slic3r a different nozzle size 0.25 0.4 actual and 0.8mm but mandating extrusion width to 0.5 This SHOULD have no effect on the flow math but there are some interesting issues detailed in the following forum posts I also did a set with auto extrusion width and the actual nozzle diameter although a small tweak here might help if the automatic values aren't optimal Print Settings Rafts No Supports No Resolution 0.2mm Infill 40 Notes Some settings may not matter, but I used 45mm/s 0.2mm layers 40% infill and 220C/90 with 1.75mm Hatchbox ABS and 3 perimeters unless otherwise noted Make sure to turn off "extra perimeters if needed" Again #0-4 have that many corners cut #5 has two across from each other I did three sets, one each with a 0.25 0.4 and 0.8mm nozzle diameter although the actual nozzle size used was always 0.4mm Inside perimeter first 15% overlap Inside perimeter first 0% overlap Outside perimeter first 15% overlap Outside perimeter first 0% overlap One perimeter 15% overlap One perimeter 0% overlap