Upon startup, the XY stage will step through a series of positions before going to its home position in the upper-left corner of the bed. If I power up with material on the bed (specifically a half-used sheet of Proofgrade acrylic) I’ve observed the stage crashing into the ends of its travel (back and/or left/right sides). It will continue crashing about until I power off the system. If I clear the bed of the apparently jinxed sheet of Proofgrade acrylic prior to power-up, the system initializes without incident. I have left other items, such as sheets of paper/cardboard and little magnets on the bed prior to this with no startup issues. Weird…
It appears I can dodge the issue by manually moving the gantry away from the home position, (e.g. front/center with the laser head under the camera) before powering up. When starting up with the gantry front/center, the startup routines seem to correctly detect travel limits - no crashing into the back or sides. So FYI for anyone else who’s experienced this startup fail.
So I’m just speculating, but I can think of a few causes:
- Something is interfering with the operation of the endstop detectors, like debris from cutting flyaway materials like paper. If someone could tell me where the endstop detectors are located, I’d be happy to check. However, powering up with the gantry moved out of the home position seems to contraindicate this as a root cause.
- Or the endstop only detects when a threshold has been crossed, such that it might be possible to position the gantry on the wrong side of the threshold detection, rendering the startup routines confused. While this could explain why starting with the gantry out of the home position dodges the issue, I’d like to think this would have been caught during the extensive testing, but ya never know.
- There is no discrete endstop detection; it’s all done with the camera and software. While that might seem clever, it also raises the potential of the startup routines being fooled by whatever’s on the bed when the system is powered up. This is my favorite theory, as I can’t locate any discrete endstop detectors, and clearing the bed before power-up seems to dodge the issue.
I confess I never read the manual - is there one? Perhaps it’s been documented that the system should be powered up with the bed cleared, in which case, my bad.
I’d appreciate any comments. Thanks!