Hi all; Allready sent this to Hubert, thought I'd add my comments to the archive.
I have used about half that roll of PETG, but have not succeeded in getting a fit that runs with minimal backlash, and will last overnight running at about 200 rpm input. Its breaking the spline off the upper edge of the cup if I make the fit tighter than about a degree of backlash. So ATM I have black PLA back on the printer, going to make 3 internal splines as close to 100mm in outer diameter so it fits the housing well. Then I'll make the last of 3 body caps out of PETG for its higher temp tolerance as these motors run hot, but if you are watching the list, that problem is fixable by using a near module, setting in1 to 0.00000, and feeding the PID's vel-cmd to in2, the output to a not to invert it so I can wire it to the two current pins of the driver chip, effectively sending 2.75 amps to the motor when its moving, but throttling it to 20% of that when its not moving. Making a 2M542 driver out of a $8 (ebay) TB6560 driver, mainly because I have 4 of the things I took out of a 6040 gantry mill I bought myself for a birthday present 2 years ago. Then I'll switch to TPU after I run the flexgear thru cura again and add 2 more vertical walls and one or 2 more bottom layers to improve its torsional stiffness. That will add a load dependent error of at least the backlash, because of the rubbery quality of the TPU, on top of the backlash, however there's at least that level of non-linearity in the output anyway due to motor shaft centering error in the printed pieces, you can actually see the speed variations as it turns slowly. Definitely not a candidate to run a telescope with even using a guide star. Last, play with the bearing carriers size to fit the new flexgear, and make them out of PETG because of the heat that telegraphs up the motor shaft. Thats the plan. Its been educational, but the repeated failures are getting old. I had zero failures with the TPU but I did have to put the whole Micro-Swiss kit at another $100 on the printer before I could use TPU, it moves the ejector drive from the left post to the top of the hot end, and which led to hot end freezeups from liquified plastic running back up into the heat sink and solidifying, until I put the OEM hot end back on the new carriage. Different internal design but its not "hi flow". PETG needs at least 250C nozzle temps to get near a usable flow. So thats the news from West Virginia and great great grandpas workshop. Stay safe and well everybody. 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
