On Thursday 12 November 2020 13:09:43 Chris Albertson wrote: > 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.
And the design file isn't in the zip. Darnit. Nothing but the .stl's. So I think I'll print them, and try to get accurate measurements for 1/8" alu sheet. The Lid itself, I just realized has all the counterbores on the same side. Except the tracks for the belt adjusting sliders. Grrr. Most of the night and its only 53% done, and the central infill, supposedly 20%, is mostly missing. I hope I can get usable measurements from it. At 65% done I had turned the nozzle back up 7C to 250C, the flow up to 70% from 62%, and at 4.68mm up its looking somewhat better. 250C is as hot as the ender 3 pro will go. I think for PETG, a bigger heater and a 270C limit would be more suitable. But it is what it is. > 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, In metal I use a 1/8th inch carbide endmill and generate the counterbore with arcgenm18.py. counterbore.py is broken. Its output won't go by lcnc's arc test at file loading. 50% error 100% of the time. Thanks Chris. > 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 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
