I'm looking at this imported step file. I see many details I'd change. For example the "bearing cap" has some M4 screws thread into holes with no threads and the blocks with the unthreaded hills look like they would break. I'd fill that area with plastic or use some big fillets. Lots of detailed design changes are needed. Some are just personal preferences (like brass inserts vs nut pockets) and others are fixing shortcuts the designer took.
Also, it would be better if the unit was designed around 608 skate bearings just because those are so cheap and easy to get but I'm not going to de-dimension the entire unit for this. But I bet this would work as-is. The idea is that you build one, see what needs changing then build a second version. After perfecting it then I assume everyone reading this owns a CNC machine, you make some parts in metal from your perfected CAD files. Certainly, the housings and output plates could be made on a hobby-grade CNC machine. That is the best use of printing from CAD files, the same files can drive CNC or 3D prints so you prototype in plastic before cutting an expensive block of metal. I bet I'd never find the exact motor the designer had and I'd have to adapt the design to whatever I wanted to use. If the goal is to drive a machine tool axis this would work as it can't be back driven like a belt of spur gear reductio can. On Tue, Jul 28, 2020 at 11:41 AM Gene Heskett <[email protected]> wrote: > On Tuesday 28 July 2020 12:52:09 Chris Albertson wrote: > > > Don't scale the entire part unless caliper show you the entire part is > > scaled too small. (this is very unlikely) Better to simply adjust > > the one hole you need to be larger. Or if it is less than about > > 0.1mm put the part on a lather and bore it out to size. I did this > > to all my timing belt rings to make them fit perfectly to the 24mm > > hubs. If you go slow so as not to melt the PLA the carbide boring > > bar works and just took off "fuzz" > > > holes aren't bothering me, other than hard toremove support crap. > What is bothering me is the incomplete mesh I saw in the movies, and that > easily fixed by changing the printer x and y scales. > > I think its obvious now that whats published is not 100% optimized. > > > The hole seems small but usually, it is because the plastic was not > > laid down perfectly and there are bumps and ridges and lines inside > > the hole. Make the hole perfect rather then making another larger > > not-perfect hole. Also it is MUCH quicker to bore the hole then > > re-print the part. > > > > The other trick I do is to make "temporary" bearings with either > > aluminum or even PLA while waiting for the real bearing to arrive. > > You could make them on a manual lathe in a few minutes and then you > > could verify the parts work and there is not OTHER problem before > > doing another 16 hour print > > > > I'd be surprised if you did not need to clean up the fine pitch gears > > with a nail file. > > They are amazingly clean after removal of the brim. 10 minute job to > clean them up. > > > Most 3D prints require some post-processing with a > > tiny file and maybe #600 wet and dry paper. A boring bar makes the > > inside of holes smooth as glass. > > > > A read a translation of the designer's blog page and it seems he wants > > to make a 6 axis arm with these. He will probably need to make some > > of the parts near the base of the arm in metal > > I wouldn't be surprised. These are, if built as published, going to have > enough backlash to wreck a 6 joint arm. What I'm getting off the > printer, does not always match his pix. Properly fine tuned it > definitely has commercial prospects to be exploited, and I can do a bit > of that fine tuning. > > 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) > 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
