internal hole size tester

thingiverse

EDIT: 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?263,129116http://forums.reprap.org/read.php?263,134103https://github.com/alexrj/Slic3r/issues/1588http://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 firs, 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 test, 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 setting 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