Do you have the "Cura Setting Guide" extension installed? If so, I think it is pretty clear. There is a diagram that shows how as the parts getts fatter the holes get smaller so to compensate use "hole expansion."
I agree, it is not clear exactly what a hole is what about slots? I think a hole is just any interior facing wall. In any case the value for the expansion is in mm, so the effect of 1mm is huge on a 3mm hole but only 1% on a 100mm hole I have two solutions for 3D prints used as machine parts: 1) design the machine to work well with poor tolerences. This mostly works if you can do a from the ground up design or 2) Put the plastic part on the lath or mill and take a thin cut to true the surface. I just did this the other day. My printed countersinks where not 100% round and smooth so I whent over the part and touched them up with a countersink cutter on the drill press, had to correct some other issue with a file, Then the parts get primed and painted. On Sat, Mar 26, 2022 at 4:57 AM gene heskett <[email protected]> wrote: > On Saturday, 26 March 2022 02:28:04 EDT Chris Albertson wrote: > > If you don't want a multiplier that you can add or subtract is the > > "Walls/Horizontal Expansion" and "Wall/Hole Expansion" > > I've seen those, set for 0 ATM. I suppose if I use the hole expansion, > and it worked for a gap as big as these bearing races, I would have to > shrink little self tapping 3mm screw holes. The explanation for each, > really isn't explicite enough. I suppose I could start with wall/ > horizntal expansion set for half the nozzle size and play with the sign > to see which way was the right way. But wouldn't that need a > corresponding change in the ID and OD to maintain the same fit? > > I'm not sure cura is recognizing that the cutaway between the races is a > hole, as Its laying a band of brim in the gap where the balls go. And its > been tieing the brim solidly to the part with a .35mm spacing, so I > risked a red line and tried a .55mm space. The preview seems to indicate > a gap now. Which should make the brim a lot easier to remove. I also lost > an hours rendering time by allowing it to cross over a space narrower > than the nozzle, but in this bearing race, there isn't such a condition. > pix from openscad attached. Still the 3% correction. Assembled, runs > nicely. So I have a set of 40/1 guts for this thing now. Whats in it now > is 50/1, and explores every nook and cranny in the printers resolution > with a .4mm PCD nozzle in it. > > > Chris Albertson > > Redondo Beach, California > > Thanks Chris. > > Cheers, Gene Heskett. > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author, 1940) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
