Motor missing steps - what we found

4896 machine with plug and play nema 34s. As the gantry was traveling, it would
hiccup at a certain point in the middle. We narrowed it down to an electronic issue not mechanical. What we found was one of the motor cables in the cable chain was loosing continuity as it traveled and bent the cable. Replaced the cable and all is good. - Might save someone some time…


Just curious, did the machine have a lot of hours on it where it may have cracked a wire from enough flexing, or was it pretty new and maybe just defective to start?

it’s over 5 years old. I think it just wore out.

I’m wondering if the cable had been damaged somehow before being installed. Maybe the damage is not visible now. Continued flexing may cause it to fail and not others?

Possible. When I used to work, I developed manufacturing equipment, and they ran 24x7. They had to have special flex ribbons instead of wireing so they didn’t crack too often. Thats always made me wonder how long the AVID cables will last due to heavy use since I don’t think they are any kind of special higher flexibility cables. Thats why I’m always on the lookout for these kinds of failures because I’m curious. One the other hand, a CNC isn’t typcially moving end to end nearly as frequently as the equipment I worked on, so maybe it just isn’t a problem.