Ian W. Wright wrote: > Hi, > > Can one of you boffins enlighten me a little please on the subject of > backlash. It hasn't bothered me before but one of my axes has now > developed a little backlash (0.06mm) and I'm not sure how EMC2 handles > it. To be specific.... I run without limit or home switches at the > moment and so when I put a new job on I first jog the axes to my known > start point, touch off and then run the program. What happens at first - > do the axes take into account the backlash as they start to move and if > so how - or, more particularly, how can they know whether backlash > compensation is needed on the first move or not. Does EMC2 remember the > direction it last jogged in? Whether or not backlash is compensated for > in the initial move obviously determines the direction I need to jog the > axes in to get to the start position. Even though the backlash is quite > small on my machine, it really matters as I am making parts for watches > and the odd thou can ruin a piece.... > Backlash compensation happens if you set a non-zero value for BACKLASH in your ini file. With compensation, EMC2 attempts to correct the last by doing a small quick move each time the axis reverses.
If BACKLASH in the inifile is zero (or missing), then EMC works just like a manual machine - it turns the dials as directed by either the program or your jogging moves. If you touch off moving right to left, and your cuts are made moving left to right, the cut will be off by whatever lash you have in your screws. Even if you have backlash compensation enabled, it is unlikely that the lash is exactly the same everywhere along your screw. So if your critical cuts will be mostly made moving one direction, it is best to touch off going that direction. Regards, John Kasunich ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
