Hey Jim,
Hello all,
that sounds familiar in a way. Perhaps my recent experience with the dual y-axis can help you any further:
I was tinkering around with the cnc function and manual written gcode for a while, when i realized that my results were sometimes way off on the y-axis. I noticed a “bump” in my y-axis, similar as described here and elsewere:
I disassembled the whole machine,
put all 5 linear rails on a table,
connected them each after the other to the controller without the y-splitter,
moved the slider with the jog in Luban to one end and 2mm back,
marked the position of the slider on the case of the rail,
moved the slider with Lubans control panel a long distance (i think it was 300mm),
and measured the distance to the initial point.
I repeated that for all modules each 10 times.
The measured distances differed from the ones entered in Luban, but the errors were nearly repeatable per module each time. I interpret that as an not really satisfying manufacturing tolerance.
I found one of my linear modules (used in the y axis before) having a repeatable difference compared to the other around 1-2mm. That caused the two modules used as y axis to build up tensions to each other when traveling distances above ~170mm , as they didn’t move the same distance. These tensions released in the noticeable “bump”, causing the y axis to “slip”.
After changing the modules for the axes and grouping them in pairs with similar errors, reassembling the machine, the control is now usable at least.
It was a low-cost and not-waiting-ages-for-support-to-react workaround after all.
What it tells you about QC at SM is another matter.