Due to relative contact frequency of pinion and rack teeth, it is very likely most wear will be on the pinion anyway.
Dave Caroline On 31/10/2013, Jon Elson <[email protected]> wrote: > Todd Zuercher wrote: >> Is there a rule of thum for judging the ware on a racks and pinion? The >> pinions are visibly worn to the point I'd like to replace them. But How >> to judge when the racks need to be replaced? This is on a large gantry >> router with two racks and pinions on either side the racks are about 4m >> long (4x1m sections). The problem is not so much back lash but a lack of >> smooth motion, giving a rippled appearance during diagonal cuts. >> >> > Probably the easiest method is to measure backlash at the center and at > the ends > of travel. if they are significantly different (looser in the middle) that > would indicate wear of the rack teeth. > > The rippled appearance could be the motion control, vibration/slop in > the linear > slides, or cyclical error in the rack-pinion engagement. measuring > cyclical > error of gears is difficult, but can be done with standard tools. You need > a dial indicator with travel exceeding the rack tooth pitch. make a series > of very short moves in one direction while taking readings on the > indicator. Graph these readings against the positions given to the > motion control and check for curvature. If it is more than a few > thousandths, > then the gear teeth may be badly worn, or just a crummy rack from the > beginning. > > Jon > > ------------------------------------------------------------------------------ > Android is increasing in popularity, but the open development platform that > developers love is also attractive to malware creators. Download this white > paper to learn more about secure code signing practices that can help keep > Android apps secure. > http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Android is increasing in popularity, but the open development platform that developers love is also attractive to malware creators. Download this white paper to learn more about secure code signing practices that can help keep Android apps secure. http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
