My x-axis is having an issue where something seems to jam its travel along the x-axis at regular intervals.
The problem:
This first occurred after the initialization phase of the machine, which happened with no issue. I wanted to double check the x/y home location (to see if I needed to do the probe to reset it), and this is where it got hung up. It’s like the speed the axis moves during initialization was fast enough, but the slower travel from the bitsetter area to the x/y home revealed an issue. It traveled a few inches and then just got stuck, so I shut it down immediately.
My investigation:
Once the machine is off, I can push the router freely along the axes (axises? lol). As I slowly pushed left/right along the x-axis, I could feel a slight bump or something every few inches of travel. SO, that told me it was one of the radial components of the movement system. I moved it to where the bump was, and made a little mark on the pulleys and bearing v-wheels and pushed again to see which marks lined up. It seemed to be consistently happening on each full rotation of the v-wheels; the mark was in the same top location each time I felt the bump when pushing.
My solution:
I couldn’t visually see any defects on the wheels, however… So what has seemed to work for now, is that I can manually move the x-axis back and forth a few times, and that seems to minimize the bump. Followed by regular initialization of the machine, and then I just jog at the “fast” speed along the x-axis fully, about 3 times back-and-forth, to continue to smooth it out. THEN, when I do the travel to x/y home, it is able to roll slowly on its own without stopping.
My conclusion:
Is there something else I need to investigate to figure out the actual problem/solution? My guess to the cause is the heat in my garage over this summer has somehow softened those v-wheels just enough that if I don’t use the machine for a week or so, the wheels settle and deform slightly; is this possible? I had recently replaced all of the v-wheels, so they are pretty new.
Usually any sort of deformity (say from over-tightening) will go away overnight if one loosens things and rotates so that the dent isn’t against the rail.
Where is the over-tightening possible on the v-wheels? I know the lower v-wheels have the off-center nut, but I have those tightened just enough that I can barely rotate the wheels by hand. This is important for z-axis stability, isn’t it?
So far, once I do my workaround to get it rolling fine, I have noticed a slight discrepancy on two cut paths that overlapped (different depths, same path in some areas). It was like the x-axis was off by maybe 0.5mm or less between cuts on the same job. I didn’t notice the jamming during that job, but I imagine there was enough resistance over the duration to have it drag slightly.
Can you advise a little more on setting feeds and speeds to ensure lost steps won’t happen? I know where to change the feeds and speeds, and have found tables for recommended settings based on material. But, are you talking about a process to make small adjustments and observe whether or not lost steps are occurring?
I can do this cut test later today. I assume this will reveal any inconsistencies along the x-axis that will show up as depth z-axis variations?
Maybe try removing your X belt completely then move Z from one end to the other noting any tight spots. If you find a tight spot, move Z just far enough to rotate the V wheels half a turn, then look down inside the V for foreign material. I’ve had aluminum chips buried in that gap a few times. Before you reassemble, inspect the X belt and the drive gear position and grub screws on the X motor.
For what it’s worth, I did adjust the tightness of the lower v-wheels… I have them maybe 1/6th of a turn looser and the issue is pretty much gone! Perhaps I had them too tight and they were squeezing the x-axis, causing matching flat spots on the wheels, which exaggerated the jamming issue. I will stay aware of other issues, as well. Thank you all for the feeback!