You can not print over the top of air. If there is an overhang you need to enable "support" in Cura. If you do then Cura will print some removable structure under the overhang.
Most people when they design parts try to design them so they can be printed without supports by avoiding overhangs but sometimes you can't avoid it. On a single extruder printer, you have to use the same material for supports as for the part. (On a dual-head printer you can use water-soluble support and get a much nicer result but that is expensive) The suggestion to make the part in metal is good. But we like to print them first to verify fit and function. Then after it is seen to work, generate the OTHER kind of g-code from the same design file and send it to your mill. But this workflow fails if you don't make both printed and milled parts from the same design file. A hybrid technique I sometimes use is to print the part with under sized holes and then machine the holes to size. The tool needs to move VERY slow so as to not heat the plastic it is cutting. Same with counterbores, OK, more details, You CAN print over air if the "ceiling" has a 45 or 60 degree slope. So make your counter-bores have "vaulted ceilings" and then after the print is finish machine the bottom of the counterbores flat. Plastic is so soft you can use the counterbore cutter by hand. I do the same with counter-sink holes for flathead screws. I "finish" them with a cutter, On Thu, Nov 12, 2020 at 9:05 AM Gene Heskett <[email protected]> wrote: > 2 scans attached if they get thru the listserver. > > I am having a problem with this part, printed right side up, I am getting > this from PETG at 250C nozzle/70C bed. The ledge in the center, > destroyed as you can see, has an overhang of about 1.5mm to retain the > bearing. Turned over, its destroying the bottoms of the cap screw > counterbores. And the supports in the bolt holes are being caught and > pulled back out of the holes, mucking up the bottoms of the counterbores > that bolt it all together. > > Suggested fixes? > > Thanks. > > 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) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > Genes Web page <http://geneslinuxbox.net:6309/gene> > _______________________________________________ > 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
