So you hear a pig singing and ask why it got one of the words in the song wrong? :-)
The reason the belt appears to have low tension is that the CAD file I downloaded had the belt in the shape of a perfect circle and PLA is a rigid plastic. So it takes quite a lot of "pull" to force the belt to over two 40T pulleys that are 140mm on center and I simply could not make the belt tight enough to make it flat. There was quite a lot of tension but the belt had a lot of "baked-in" curve. The fit is very tight on the pulleys. It has similar tension that a real belt would have. This worked so well that I might try my spool of medium soft TPU plastic. I bet I could print a belt that might last for weeks. But then it might work worse bcause TPU can stretch but PLA doesn't. I ordered real Gates brand belts to be here in a week or so. On Wed, Jun 10, 2020 at 8:50 PM John Dammeyer <jo...@autoartisans.com> wrote: > First of all, very impressive! > Is there a reason you didn't have higher belt tension? > Thanks for that video. > John > > > -----Original Message----- > > From: Chris Albertson [mailto:albertson.ch...@gmail.com] > > Sent: June-10-20 8:15 PM > > To: Enhanced Machine Controller (EMC) > > Subject: [Emc-users] Stupid CNC stunts. A 3D printed timing belt. > > > > There was a question on another thread: "I wonder if you can 3D print a > > timing belt?" That I think was intended as a joke. But I thought it > > sounded like such a dumb idea I'd have to try. So I did. > > > > I am converting a Harbor Freight Mini Mill to CNC and have now made all > the > > parts. Except for standard off the shelf hardware, all the parts are 3D > > printed. I want to work out the easiest path for CNC conversion and > then > > publish it so as to allow more people to have CNC capability. So I'm > now > > assembling parts and needed a belt. I was able to make the conversion > to > > CNC with no machined parts. > > > > I fully expected the belt to fail as soon as I applied tension. It > > didn't. Then I thought that as soon as I'd rotate the pulley the belt > > would break. it didn't so I fired up LinuxCNC and ran the splash > > screen forwards and backwords and got bored after it just worked about 8 > > times back to front. > > > > About the belt. I went to the SPD/SI web site and found a 133T, 3mm > pitch, > > 9mm wide GT3 profile belt and clicked "download CAD file". I printed > the > > file with no modifications and using the defaults setting in Cura with > PLA > > plastic. PLA is a hard plastic not noted for being flexible. > > > > Below is a video of the belt in operation. It is also the very first > time > > this mill has moved under computer control. It is just the bare minimum > of > > parts installed for this stunt. The Z and X motors are laying flat on > the > > bench. The Z motor has a bad driver and is *very* noisy (and > replacements > > are out of stock). I placed a bit of blue painter's tape on the belt > so > > you can see it move. > > > > https://youtu.be/GPXICb9rSoE > > > > > > > > -- > > > > Chris Albertson > > Redondo Beach, California > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
