I've been following this list for a couple of years, hoping that perhaps through osmosis, I would learn enough about Linuxcnc to convert my old Bridgeport R2E4 to a modern control. The first step towards that endeavor was to build a Mesa/stepper motor based, cnc router and learn a little LCNC along the way. The router project went very smoothly, especially given how little I initially knew about LCNC. Tackling the servo based R2E4 was still pretty far outside my comfort zone however. Getting all of the servo stuff set up properly seemed like it posed enough challenges that I didn't want to kill a working mill just for the sake of upgrading the control. I kept putting off changing out that old, slow, Motorola 68k based control until it gave up the "axis enable" ghost a couple months ago. For all intents and purposes, the machine had become a boat anchor overnight. At that point I figured I had little to loose by tearing into it. Since I had all of the schematics to the machine, I started mapping out all of the gazinta's and gazouta's. All pretty straightforward stuff. Next I moved into the cabinets and removed everything but the large analog axis drive power supply, the large contactors (for drive enable, spindle forward/revers, etc), the wiring that went to the axis drives/encoders, and much of the fundamental cabinet-cabinet wiring and power distribution. Snip Snip and I had a heaping pile of circuit boards, card cages, wires, etc. Since the old servo drives were now in the junk pile, I needed to find a replacement that would work with Mesa hardware. My good friend pointed me to these step/direction <https://cnc4pc.com/catalog/product/view/id/504/s/dg4s-16035-dc-servo-drive/category/88/> based servo drives which have servo tuning firmware built into them. (anyone else use them? feedback??) I installed new encoders on the servos and wired everything up. A few solid state relays were added to drive the air brake solenoid, spindle speed motor/sheave, forward/reverse contactors, etc. from the Mesa card. Even added a 4th axis channel. For the smoke test, I opened all of the circuit breakers, and slowly brought the machine up one breaker at a time. No smoke! After basic LCNC configuration, we had motion and made chips. Everything worked like a champ and it was a fun project that only consumed about 4 weekends of my time. (thankfully, that mill is a hobby, and not my livelihood!)
And now for my question. The old Bridgeport had a button on the front panel titled "No Z" that turned off all z motion and let me "air mill" a part as a sanity check of my X & Y boundaries/fixtures. I can't find the equivalent functionality in LCNC and was wondering if anyone here has done this, or knows the best way to implement it. (the LCNC display certainly shows the part and the toolpath, but for me, it's so much better to see the part actually move under a motionless cutter) Ideally, I would like to have a button in AXIS that performs that task much as it did on the original Bridgeport control.
Many thanks to all of you talented individuals who contribute here! Brent ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
