I have wired up one of the PPMC DAC channels to control the VFD, and added an abs HAL component to get the unipolar spindle speed command. My first cut at rigid tapping just jammed the VFD from forward to reverse command, which was so abrupt it caused Z-axis following errors at higher spindle speeds. I have a lowpass component in there also to make the speed change more gradual. This seems to work really well, I was "air tapping" at 1500 RPM, and it all ran very smoothly. I will have to try it with an actual tap, but it certainly looks like it will work fine. I wrote a C program last night that takes in a list of X-Y coordinates and writes G-code to spot, drill and rigid-tap the holes.
(I have some work coming up that will require a lot of 2-56 and 6-32 holes, so I wanted to get this running. I have rigid tapping working on my minimill, but I have some doubts about the accuracy of that machine, also I can't put a 6" milling vise on it.) Jon ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
