Hey everyone, I bought a Shapeoko Pro, standard size, in October and finally got some time to use it. I have a major problem and can’t easily find a relevant post: my y-axis seems to be slipping badly and often. After maybe 10 projects, some of which I have gotten through with no slipping, I started to hear a grinding sound from what my bad ears suggest is the left y-axis motor.
During the last project I tried (image attached), it got far off the y-alignment - the words here are all about an inch too far down on the y-axis, but as it continues (traveling left) it keeps getting further misaligned (obviously the words are all supposed to be on one level). Occasionally, I have seen the machine jerk while moving in the y-axis. In the end, in addition to the misalignment here, when I haven’t noticed a small misalignment and changed a bit, the machine has missed the bitsetter, so it clearly is just misaligned.
I have cleaned everything I have access to on the machine, and I have tightened the y-axis belts as much as I reasonably can - I feel like they’re a notch too loose, but I have spent an hour or two trying to get it tighter and simply cannot figure out how to unless I get some longer bolts. Even if the belts are a hair too loose, that can’t explain the motor grinding.
Do I just need to buy a new y-axis motor and hope that’s it? Or is there something else I may have to do here?
thanks, I had tried to read that post several times before and I haven’t connected it to my exact issue - although now that I read it closer I certainly will check belt tightness using the tone-measuring app. But I still don’t see what the connection to the exact alignment problem I’m having is? Is the suggestion that the difference in tightness between the two belts means that the alignment is bound to get off a little at a time? If so, that doesn’t seem to be what is happening - the machine will sometimes run for an hour, and then start slipping. Does this not indicate that I have a different problem than that? I am asking out of ignorance - I am totally lost here.
With the oil, I had not fully understood this… and I promise I will do better. But that’s not what’s causing this either, is it? It doesn’t explain the grinding sound that seems to be coming from inside the motor… again, excuse my ignorance
The other thing to check is the pulley set screws — are they both securely in place on each pulley?
Put a “witness mark” across the end of the motor shafts/pulleys so that you can see if they shift.
Lastly, verify that all the wiring connections are secure and in good condition and don’t shift at all as the machine moves through its full range of motion.
When I see skipped steps in the linear rail equipped machines… my first question is have the rails/ bearings been lubricated. Many people highly underestimate the effect dry bearings has on resistance.
The stiffness of the linear bearings when they get below the critical point of maintaining an oil film for the seals and bearings rather takes you by surprise, you expect them to get stiffer and offer more resistance. On my machine, which got linear rails as a modification, the wiper seals just seemed to weld themselves to the rail and I could barely move the blocks at all, a little Mobil Vactra squirted into the lube ports on the blocks and suddenly the brakes were off and the machine was moving again.
The other upside of keeping the rail blocks lubricated is the constant flow of oil out of the blocks and onto the rails helps a lot to keep things clean inside.
