Thanks guys, Yet two more ways of dealing with this. The hardest part when adding CNC to the knee mill was switching from the CNC router where the XY motion and Z motion appeared more logical. All cutting with the CNC router was done with a PC board as an electrical touch pad 0.062" thick and the macro I wrote for MACH3 was adequate for finding the top of the work and setting that to zero. All cuts were then deeper than that and in a negative direction (negative is closer to the spindle).
But now with TTS tool holders that are referenced to the bottom of the spindle a different approach is needed. Using the PSNG Probe screen I didn't like the constant probe tool length for each tool change so I added the "Alkabal Tool Probe and Tool Setter instructions" and the M6-Remap. Now the if the value in the tool table is non-zero then use that on a tool change like M06 Tnn G43. However if the tool length is 0 then use the tool setter. So the TTL holders with drill chucks are probed because we don't know what drill bit is in them. He has a separate G-Code file he runs to measure the tools and enter the values into the tool table. That makes some of the parts of the PSNG screen somewhat confusing. Should I check 'Auto Zero' or not? I don't remember now if it was the original PSNG or the M6_Remap that smashed my probe into the work after restoring the wrong Z value but since then I've become more careful. I agree with Stuart that Z = 0.000 is as far away from the spindle as possible. Since it's the knee and table that move while the spindle doesn't I've made my XY home positions be such that a move away from the home moves the cutter over the table in a graphical upwards direction and more positive. Same with the X. Although the table moves to the left the path of the tool in the spindle is positive and to the right over the work. Other than machine world co-ordinates for the tool change location and the tool setter location XY isn't important for the G5_.Z work Co-ordinate when locating the tool tip. The Alkabal approach uses 4001..4009 in linuxcnc.var as permanent locations by editing the .var file to have those entries. Where I got confused is to then see some of his code switch to G59.3 work space. Anyway, so far a fixed value in the tool table correctly changes the offset so the tip of the new tool is still at the G54.Z zero position because the G54.Z offset is changed to reflect the new tool length. _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
