> > > Martin, > I have been using CamBam for 7 of 40 trials. I am amazed at how easy it is to use so far. I drew a mount for a stepper motor that has a cutout profile with tabs, a pocket for the rim of the stepper and four spiral holes sized for tapping 10-32. With all this advice, I already cut a part in plastic that fits the motor.
Jon, That is good advice too. I will look for backlash. How do I make it go awayif I find it? The mill is a Taig. Thanks, marty > > Martin Patton wrote: > > Hi EMC users, > > I have EMC running on an old pc, latency number about 25000. I got an > >occasional real time error with latency number set at 22000. > > I drew a part in CamBam, generated some g-code and cut a part. The part > > looked right but the caliper says every dimension cut a little small. A > > circle pocket drawn 1.50 diameter cut about 1.42 in diameter, The tool > > diameter matched the tool specified in the cad program. Is there a good > post > > on calibrating for a stepper motor machine? > > > First, you need to measure the actual movements with some kind of > measuring tool, even if > it is just using a dial caliper. You need to separate linear movement > error, backlash and > tool deflection. Without separating these different error mechanisms, > you will not make > the right correction. Linear error is pretty easy, put a pin in the > spindle and measure between > it and a block fixed to the table. If you move in the same direction, > backlash will not > alter the reading. Moving a number of inches so as to use nearly the > full range of the > caliper will give the most informative result. > > Then, approach the same coordinate from both directions and measure > position. > This may be harder to do with a caliper, as hopefully your backlash is > relatively > small. It is best to do this with a tenth-reading dial test indicator, > if you have or > can borrow one. Backlash alone could cause the error you report above. > It will also leave 4 steps in the walls of a circular pocket, at those > places > where the axis needs to reverse, but takes a moment before the linear > motion > picks up on the other side of the backlash. If your problem is > backlash, these > steps should be really obvious on the part you mention above. > > Finally, it could be tool deflection, which will cause milled pockets to > come out > small. (Your measurement above seems to big to be tool deflection, > however.) > But, tool deflection will NOT leave bumps in the wall like backlash. > > Jon > > > > ------------------------------ > > ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2dcopy2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
