On Friday 08 November 2019 16:53:31 Thomas D. Dean wrote: > On 11/8/19 5:37 AM, Todd Zuercher wrote: > > I could see worn pulleys on toothed drive belts, and/or over > > tightened drive belts giving results with delayed backlash take-up > > like that. > > I am using a Sherline CNC Lathe. There are no belts or pulleys > associated with axis movement. > But there can be force related windups in the motor to screw couplings, but thats generally ignoreable with the use of spring cuts. More so with one piece spiral spring couplings than with elastomer spiders, but with ball screws not terribly important.
In this case i'd put a dial on the end of the screw to see how much end play might be showing. When I have designed stuff that might have end play, I choose which end of the screw is to be referenced and use a teeny caged ball with loose washers, and bring up the nut restraining the endplay until there is none at that end of the screw. And I generally sink the complete 3 layers of the bearing into the housing with zero clearance from the housing pocket to the edge of the outside washer. just to keep dirt and swarf out it it. Works well for me. > > Todd Zuercher > > P. Graham Dunn Inc. > > 630 Henry Street > > Dalton, Ohio 44618 > > Phone: (330)828-2105ext. 2031 > > > > -----Original Message----- > > From: Thomas D. Dean <[email protected]> > > Sent: Friday, November 08, 2019 12:30 AM > > To: [email protected] > > Subject: [Emc-users] Axes Names, Backlash and Overshoot > > > > I have a Sherline CNC Lathe with the computer system from Sherline. > > The disk drive failed. I replaced the disk and installed LinuxCNC > > 2.7.14. The install completed without error - great job. > > > > I have a problem with backlash and overshoot. > > > > The config file has a strange entry: > > AXES = 3 > > COORDINATES = X Z > > > > Should there be names for 3 axes? > > > > I checked the motion with a Fowler digital dial indicator. > > > > Backlash = 0.000 > > Motion Fowler > > Start +0.0001 > > -0.0100 -0.0080 moved -0.0081 > > -0.0100 -0.0175 moved -0.0095 > > -0.0100 -0.0275 moved -0.0100 > > -0.0100 -0.0375 moved -0.0100 > > +0.0100 -0.0305 moved +0.0070 > > +0.0100 -0.0210 moved +0.0095 > > +0.0100 -0.0110 moved +0.0100 > > +0.0100 +0.0010 moved +0.0100 > > > > Backlash = 0.0020 > > Motion Fowler > > Start +0.0100 > > -0.0100 +0.0005 moved -0.0095 > > -0.0100 -0.0075 moved -0.0080 > > -0.0100 -0.0175 moved -0.0100 > > +0.0100 -0.0055 moved +0.0120 > > +0.0100 -0.0010 moved +0.0045 > > +0.0100 -0.0110 moved +0.0100 > > > > Backlash = 0.0030 > > Motion Fowler > > Start +0.1245 > > -0.0100 +0.1135 moved -0.0110 > > -0.0100 +0.1065 moved -0.0070 > > -0.0100 +0.0960 moved -0.0105 > > -0.0100 +0.0860 moved -0.0100 > > +0.0100 +0.0990 moved +0.0130 > > +0.0100 +0.1060 moved +0.0070 > > +0.0100 +0.1155 moved +0.0095 > > +0.0100 +0.1255 moved +0.0100 > > > > Backlash = 0.0035 > > Motion Fowler > > Start +0.1260 > > -0.0100 +0.1140 moved -0.0120 > > -0.0100 +0.1075 moved -0.0065 > > -0.0100 +0.0970 moved -0.0105 > > -0.0100 +0.0875 moved -0.0095 > > +0.0100 +0.1010 moved +0.0135 > > +0.0100 +0.1080 moved +0.0070 > > +0.0100 +0.1175 moved +0.0095 > > +0.0100 +0.1270 moved +0.0095 > > > > I do not understand the relationship between the variables in the > > ini file. Except for the backlash, I have not changed anything from > > the distribution file. > > > > How do I fix this? > > > > Tom Dean > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > Tom Dean > > > _______________________________________________ > 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
