markaudacity

“Note that if you paid the typical $50,000 for an injection mold, some poor engineer would have to take your model and make tons of changes to it so that it could be made in an injection mold“ Sure, absolutely. Injection molding is not a rapid prototyping technique, though, and to expect the same level of pre-processing to get a good result from FDM as from injection molding is a bit out of scale, I think? FWIW, PrusaSlicer never had this problem, even on a trashed Prusa Mk2, so I don’t think it’s entirely universal to the medium. I would expect a bit more from Cura? [I get that inches are stupid, believe me, but since this is an English-language forum and since almost all native English speakers, and thus most native-English-speaking makers and manufacturers, use inches, it’s not that crazy to expect folks to know that .020”=.5mm 😉]

I am familiar with the difficulty of accurately depositing an inner radius with FDM—someone has described it as "trying to draw a circle with snot" 😄 My experience so far is with this occurring with small holes, and usually by a nozzle diameter or two, but I have a part with a 1.129" round hole that prints at 1.09 and a .631" hole that prints at .603 with a .4 mm nozzle—an enormous discrepancy. Exterior dimensions are within .002", so I know it isn't a scaling issue. There has to be a way to compensate for this without having to change my model to dimensions that will be wildly out of spec once I cut them in aluminum. Halp!