In the past when this I and J error would arrive . I would go back to qcad and convert the drawing to metric. Then recompile the gcode in metric which would usually work for me. Only a suggestion. Jim
On Tue, Sep 24, 2019 at 12:36 PM John Dammeyer <jo...@autoartisans.com> wrote: > > On 09/23/2019 10:35 PM, Chris Kelley wrote: > > > > > > > > > I suspect the problem lies in the method for calculating CentDist on > line > > > 148. I'm not sure that method actually produces a I or J coordinate > that is > > > equidistant from both the start of the arc and end of the arc, > regardless > > > of decimal precision. > > > > > > > > OK, I have to admit that I have only used this program in > > the R arc mode, so it is possible I screwed up the I J > > calculation. It is not a true spiral, it is a set of 90 > > degree arcs with the radius increasing slightly every > > segment. I've used this for 20 years in the R mode with > > good results, though. > > > > Jon > > Hi Jon, > It works perfectly in the R mode for me too. And with MACH3 even in the > IJ mode without complaint. But LinuxCNC is correct when it reports that > the Radius is different between the start and end positions by up to as > much as 24 percent. > > Doing it by hand and trial and error I was able to do 90 degree arcs like > the R mode but the exact calculations to get there still escapes me. I > think partly because I was not using the center of the hole as the starting > position. For the Mecsoft AlibreCAM example I put the workspace origin in > the hole center so I could see the symmetry for positive and negative > movements. But of course your program has an offset called starting x and > y which is more logical if we're working off a drawing and positioning the > tool bit at the center of each round pocket (hole). > > What I'm trying to do, and it's really a complete waste of time for me > since AlibreCAM does it for me, is figure out how to modify your program to > properly generate the IJ values. I don't like not knowing. I'll be able > to get back to this later this afternoon. > > But do notice from the attached screen shot there's a 1" radius circle and > then three quarters of a spiral starting at the same spot. The first two > I,J parameters have one each set to 0 as your program does. But the third > 90 degree arc now adds in the -0.05 width of cut offset into I while J has > incremented by 0.05. So the state machine that determines I and J has to > be a bit more complicated. It's doable. Just not sure how yet. > > John > > > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
