hendrik wrote:
Hi,
this is my first post here, as I’m just getting started with my Maslow 4.1. Yesterday I wanted to do my first cut, but it didn’t go well. Here’s what’s happend:
welcome
Setup: I have drilled holes into my concrete courtyard (roughly 3000x4000 mm) and installed 8mm bolts, because that’s what I had at hand. To prevent the belts from rubbing on the ground and collecting too much dirt, I added spacers to keep the ends of the belts about 20mm above the ground.
Calibration: I did that a few days ago and I think this went fine. Fitness 0.59, tlX=44, tlY=3229, trX=3850, trY=3179, blX=0, blY=0, brX=3830, brY=0. Unfortunately I haven’t saved all the serial output, so I can’t say anything about the stiffness measurement or other information printed during calibration. I guess that’s part of my learning curve …
the calibration should probably be done over, when you added the spacers to keep
the anchors out of the dirt, you probably ended up with a different height from
the anchors to the sled, so the Z offset values in the settings need to be
adjusted
Yesterday’s crash: Temperature was about freezing. I wrote a simple gcode file
to move to the four corners of my part so that I could align my wood. Extend
the belts, take up slack, Maslow says it is at -89, -5 (out of my memory,
maybe there is a sign or coordinate flip, but that’s the numbers). Maslow jogs
fine, I start my gcode and as Maslow approaches the first corner, I push
“pause”. Maslow stops and loses network connectivity. I can’t reconnect, so
finally I decide to power cycle Maslow. I’ve seen WiFi problems in cold
conditions on ESP8266 and (less) on ESP32 before, and there is another thread
here mentioning it:
Communications and belt retraction issues on a cold day.Anyways, after the power cycle Maslow reconnects to WiFi, so I do “release
tension, take the belts off the anchors, retract belts, extend belts, put them
back on the anchors, take up slack” (is this actually required after every
power cycle?). Maslow reports “0,0,0” as position, which I find surprising, so
I try to jog in y-direction. First time nothing happens, so I try jogging
again. Now one belt snaps just a few mm from its anchor point.
you are the second person we’ve had report that the belts snapped in cold
weather. One can be coincident, two is looking like a problem @bar
After the belt had snapped, I realized that the bolt I used as anchor is now
bent by ~30°. One other anchor bolt was also bent, but much less. I believe
that this bending contributed to the snapping belt by causing much more
tension on one side of the belt than on the other side, thus tearing it across
its width rather than just pulling along the main direction of the belt.
wow, pulling hard enough to bend an 8mm bolt, it may be that you are just plane
pulling too hard.
After you setup again and are ready to do another calibration, touch base with
us to help make sure your Z offset values are plausable and please post the
resulting maslow.yaml file after you finish calibration
Now I wonder:
- Did I underestimate Maslow’s pulling force and my 8mm bolts are too weak (especially as they are not supported at the top)? Do I need stronger anchors?
- Or does this sound like an issue with the belt tension measurement?
- Did the cold weather contribute?
- After the crash I also realized that Maslow complained about a “center point deviation (BL -13.2, BR 6.7)” when setting it up again after the power cycle. Was that the reason it didn’t want to jog? Were the bolt already bent after taking up the slack (they were still straight when I put the belts on)?
I think I answered these questions above, if not, ask for clarification.
David Lang