I’m seeing a recurring issue on my Shapeoko 5 Pro and would appreciate advice.
Problem:
During a job, the Y axis will occasionally lose sync and the gantry racks out of square, as if one Y motor momentarily stops. It has happened on both the left and right sides at different times. I hit stop, power down, manually re-square the gantry, re-home, and can continue for awhiile—but it eventually returns.
When it happens:
Mostly during finishing passes in maple. Typical finish parameters:
Feed 80–120 IPM
DOC about 0.050"
RPM 16,000–18,000
Plunge 12 IPM
Slowing to about 50–75 IPM lets me complete the job, but the issue comes back at those higher ipms.
What I’ve checked so far:
Reseated both Y motor connectors at the motors and at the control box; inspected drag-chain run for pinch/strain
Motion feels smooth by hand with power off
Control box is warm but not excessively hot
Couplers feel tight, though I haven’t fully re-torqued set screws/shaft nuts yet
Regular lubrication of rails and ball screws (weekly)
Working theory:
This may be torque/load related at higher finish feeds in maple with the 1/4" downcut (chipload a bit high for a finish pass), but I want to rule out an intermittent wiring/connector issue, stepper driver thermal cutoff, or a mechanical issue with the stepper-to-ballscrew couplers or ballscrew preload.
Questions:
For SO5 (ball-screw Y) finishing hardwoods with a 1/4" mill, what feed rates have proven reliable for you?
Are there known weak points in the Y-axis wiring/harness/connectors that can present intermittently even after reseating?
Has adding a small fan on the control box helped anyone avoid stepper driver thermal trips?
Any specific checks you recommend on the stepper-to-ballscrew couplers or ballscrew shaft nuts/preload on the SO5?
I’m mid-way through a large contract, so any proven troubleshooting steps or parameter adjustments would be greatly appreciated.
Don’t assume the couplers “feeling” tight not being the issue, this could just be the coupler set screw in a bind with the ball screw shaft in the last direction the motor was directed to rotate in.
You mention chip load might be high (actual calculated chip load or visual operation?) for the finish pass. I would have to ask why such a high chip load for a finish pass? A high chip load sounds like a roughing pass?
Either way the gantry racking leads to believe its driven off the drive system itself for reason you have mentioned above.
I have never racked the gantry out of square, I have however stalled the spindle by mistake.
Quick clarification: the failures are on the final contour/part cutout pass. Recent settings were 1/4" 3-flute upcut in maple, 18k RPM, 120 IPM, ~0.050" doc, 12 IPM plunge. The chipload works out to ~0.00222" IPT which is okay on paper, but I’m realizing maybe the full wall-height engagement can spike load enough to upset the Y axis maybe slower feed will help torque drop after all these motors aren’t that strong.
Full depth of cut on the last pass can make a difference, especially when actual cut depth of the bit is over an inch. Lots of factors we can’t see that can cause chatter and deflection. You never mention total DOC of your material. I do not calculate chip load. I started with standard settings and based on the sound of the spindle/bit is what I’m adjusting for. I’m not running in a business environment either so I’m not as aggressive as I could be on the machine. I do know my finish pass is a very light cut to minimize deflection/chattering, especially in the hardwoods like maple, Black Olive and Ipe etc.