I've been tinkering with & sort of designing, modding 3d printers for 6-7 years, and I've been following some build doc's for a CNC router frame that i think should work. I've tried to run grbl though with a few frames before, and am confused what to do with end stops, and limit's in general. I.e. it usually locks up when it hits end-stops. I can't tell if i just shouldnt bother, and have soft limit's or what I'm supposed to do. When i was learning 3d printing, there where some pretty specific guides for cartesian's that really got most of the basics accross. Things i have : control board(s) - grbl from amazon, CAM X TOOL clone ramps w/ repetier in laser engraver mode steppers, a basic threaded rod x/y frame 2040, rubber V wheels. 24V psu laser 5 watt from Creality 2 working 3d printers.
As it should. Hitting a limit means something went wrong. Machine crashed, lost position. You have to lock up to prevent more damage. Operator comes in, unlocks, rehomes - clears whatever caused a crash in the first place, fixes whatever got damaged in the crash, etc and then restarts (usually stock is ruined, etc - so start as in start over) Homing + Soft Limits prevents bad GCODE from crashing by checking the move before it is executed Hard limits prevent crashes from more severe issues (lost position, skipped, crashed into clamps/stock, etc) where know one could know it would crash Read the Grbl Wiki (Yes, the WHOLE thing) - knowledge is power: Home · gnea/grbl Wiki
thanks.. I've looked at it before.. but never quite in a 'grind thru it for learning' . usually looking for something specific. That reminder led me to this Frequently Asked Questions · gnea/grbl Wiki which has the gem that Grbl assumes certain travel directions, but also ANY endstop trigger condition. Then the next FAQ about coordinate direction, adds the 'converting mentality' bit that i need. @Peter Van Der Walt : THANK mate! i think i finally got it.
Travel directions are critical to the safe and successful operation of a cnc router. Limit/home switches at the positive ends of travel ensures all industry standard Gcode will work safely and correctly. 'safety' and 'industry standards' get mentioned because a 700watt router will slice through flesh and bone (and iPhone left lying around) without even slowing down. Standards exist because people died! What you will really like is a Blackbox. Easy to wire up, easy to set up software (much easier than Repitier and Marlin) and designed for the purpose of running a CNC router (but will run a laser or eggbot too). Remember that the router must have nema23 motors, which require more current than the tiny Ramps drivers can handle even with extra cooling.
