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Post by mundo161 on May 3, 2023 23:01:53 GMT
I have a mega v standard with a 19" X 19" working area. How do I figure out the perimeter of that 19" area so I know where I can put my work piece to get the total use of the machine?
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Post by bLouChip on May 4, 2023 11:35:51 GMT
Good question. It's a tight fit isn't it.  I recall that after fooling around for an hour or two and experiencing a couple of end point crashes while trying to get the full 900x900x100mm, I came to the conclusion that I'd rather give up 10mm or so on each axis and live with it, not a big deal. Also, due to modifications I made to my machine with 3" vacuum hose for exhaust fumes, plasma torch holder, and rigidity struts front and back of Y rails, I have 790mm of Y distance work area. So my work area dimensions are 890x790x90mm. Just update grbl config $130-$132 with correct max travel distances.
But to answer your question, to setup the work area relative to the rails, you start with releasing the rail mounting screw on the homing switches so they can be adjusted. I recall placing the X carriage and gantry to the extreme homing switch corner where the wheels of each touch the interfering member, then back them off about 5mm. (This backed off space is necessary because when homing, the 'fast seek' phase needs some overrun distance due to reaction time of grbl 'seeing' the switch close and commanding the motors to decel and stop.) At these positions now adjust the homing switches so they are just "made" (closed) and lock them in place. I orient these switches so the actuator 'leans' into the interfering member in order to close the switch. In the case of Z axis, hard stop interference with the Z carriage occurs at the lead screw-motor coupling, I back off from that point by a larger amount because that collision will screw you royally, requiring more than simple recovery.
I run with softlimits enabled, $20=1, and this prevents end point crashes unless something unusual occurs during XYZ motion which causes steps to be lost.
btw- don't increase the 'fast seek' homing speed, factory setting is 800mm/min, $25=800; increasing this seems like a good idea I know, but that just makes it necessary to have more overrun space and the switch actuator can't take it either.
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I recall that after fooling around for an hour or two and experiencing a couple of end point crashes while trying to get the full 900x900x100mm, I came to the conclusion that I'd rather give up 10mm or so on each axis and live with it, not a big deal. Also, due to modifications I made to my machine with 3" vacuum hose for exhaust fumes, plasma torch holder, and rigidity struts front and back of Y rails, I have 790mm of Y distance work area. So my work area dimensions are 890x790x90mm. Just update grbl config $130-$132 with correct max travel distances.