I am using the openbuilds black box with an off brand frame and nema23 motors. For some reason it keeps losing its zero position. I am using the openbuilds xyz probe to set zero and randomly the machine will lose position during the middle of a run. I have grounded the shield on each of the motors, placed ferrite rings on wires for motors, spindle, stops and usb. I just can’t figure out what to do next. The picture is of a cut where it cut pockets for a gear, then cut profile for a desktop, then when it went to cut the profile for the gear and it lost zero in both x and y. This was all one gcode file and one bit.
Despite your precautions emi sounds like a probable cause - have you got any mains and spindle cables well away from any signal or low voltage stuff - especially the usb lead? How long is your usb lead? Alex.
Specs of those suitable for the BlackBox? Other checks: - loose wiring causing intermittent disconnect - loose mechanical components (shaft coupler grub screws, pulley grub screws)
I can work on cleaning the wiring up a bit. I suppose it might make sense to move the VFD to the opposite side of the table away from the black box signal wires. Could it be that things are too close together?
Yes that is quite close, docs:blackbox:faq-emi [OpenBuilds Documentation] relates Though EMI doesn't usually result in step loss, usually easier to see it mess with false Limit triggers and USB disconnects, so do check over the mechanicals too
I I get it, it would have been best to buy all my stuff from more reputable vendors. However, it is my first venture into this stuff and I didn’t do my research well enough. With that said, I am still not educated enough yet to answer your question on the motor meeting specs.I searched a bit and didn’t find specs. As for loose wires, I will do some checks. Would a loose wire cause a loss in both x and y position at the same time?
Look for a model number on the motor. Post it here and we'll see if we can google up a datasheet. Probably not. But a incorrectly spec'ed motor will stall out during seek moves between cuts. Which are often XY at the same time. Workaround might be OK (turn down acceleration and max rate settings in Grbl Settings - putting brakes on the machines capability to keep up with bad motors)
Specs doesnt look too bad (if they are true) Try turning down Acceleration and Max Rate for your X and Y axes in Grbl Settings, then rerun file as an aircut and see if it still stalls during the fast seek moves between cut sections
1 more question... if the motor stalls would I hear it make a different sound or noticeable see it stutter? Or, can stalling be imperceptible? I will slow the speeds down but prefer not to do so.
Thank you both for the responses. I have ordered som shielded cable so I can move the VFD further away from the black box. I will probably get the move done and slow the speeds down next weekend. Then, I will get some test cutting done and report back.
