After completing calibration (yay!) I am seeing that when I begin to give move commands to the machine, the bands on the opposite side are a bit looser than I would expect.
Does this sound like expected behavior, or do I need to re-calibrate/repair something? Thanks!
I am seeing similar behavior, but specifically with my lower right belt. I’m in the vertical orientation, so the upper belts are always taut.
Just to confirm, which firmware version are you on?
0.70. Thanks!
I’m on 0.70.2, so updating might not do anything for you, but here’s the thread with the newest release. It’s more up to date than the github.
I’m going to run another calibration and see if that helps, since it should become more accurate after that, but I’m going to do a test cut first to see how much of a difference it makes for this on mine.
Aaron Richards wrote:
After completing calibration (yay!) I am seeing that when I begin to give move commands to the machine, the bands on the opposite side are a bit looser than I would expect.
The belts should not be loose, when you did the calibration, were the belts lose
as the measurements were taken?
note that if you needed to increase retraction current, you probably need to
increase the calibration current to match.
David Lang
I’ve seen something similar and specifically with the lower right belt. I think that maybe it has something to do with the z-axis height compensation code since the top left and bottom right arms are higher up.
It’s something that I’ve seen too and I’m looking into it so I don’t think it’s a you problem at all.
I finished my calibration yesterday and received good calibration values. During calibration, all belts where taught during moves (toward the end).
When jogging, top left and bottom right spool out waaaay too much belt. I centered and moved diagonally from bottom right to top left which should have a matching amount of belt move but it spooled out almost double on bottom right.
Just had a similar problem with jogging left … went almost 6’ from center when it was set at 100mm!
Mine moved a reasonable distance (did not actually check it) but it just spooled too much cable on the “push” side.
We had a very similar “push” problem. On our recent calibration, other than the extra slack on the first 9 points, everything was smooth and tight UNTIL point 81. After 81, there was a major move from bottom right back to bottom center, and then back to middle. On this move ONLY, the bottom right arm spooled out a ton of slack. Thankfully we were watching it. First time through we pulled the power on it to prevent it from eating itself in a tangle. Second time through it did the same thing, but I manually arrested the pushing until it got into position.
I’m having a hard time visualizing what that entails. Can you elaborate?
On the move from the bottom right of the calibration matrix to the bottom middle and then to the center (in point 80-81) it seemed as though the bottom right arm went into “extend mode.” As tension was pulled by the move it started to unspool rapidly.
The first time I didn’t notice until it was almost too late and it would have tangled.
The second time I applied pressure to the external side of the bottom right belt. Because of this, even if it was in “extend” mode, it didn’t extend rapidly because it wasn’t triggered by the consistent movement of the belt.
Hi bar,
Was this resolved? I am having a similar problem using the latest firmware (1.12).
Cheers,
Scott
I may be seeing the same problem. I wasted all of today trying to get calibrated and performing my first dry run and I’m at the point of giving up.
Mike wrote:
I may be seeing the same problem. I wasted all of today trying to get
calibrated and performing my first dry run and I¢m at the point of giving up.
If your belts are loose while you are doing the calibration, you have no hope of
things working well.
loose belts during calibration are due to the machine pulling up to the current
limit and deciding that they are tight.
The calibration current limit can be increased
but the real problem is the mechanical movement in the arm. you may need to take
apart the arm that’s not working well and figure out why it’s taking more force
to turn.
it could be that the spool is a tight fit and needs to be sanded slightly.
it could be that there was no lubrication
it could be that something has been rubbing and there is now plastic poweder
mixed with lubricant gumming things up
it could be that the gear on the motor is rubbing against the arm.
David Lang
no, the belts were loose after calibration when I jogged or tried dry run gcode. any move away from the bottom right caused it to unspool more than necessary, and with no tension, the motor started to run away
Mike wrote:
no, the belts were loose after calibration when I jogged or tried dry run
gcode. any move away from the bottom right caused it to unspool more than
necessary, and with no tension, the motor started to run away
If the belts were loose at the calibration measurement points, or the end of
calibration, you will need to go through calibration again.
either increace the calibration current, or fix the arm that’s not pulling
tight.
David Lang
I think he might have had a typo. As in they weren’t loose. I’m having the same problem. they aren’t loose at calibration and then during cutting, when moving away from said arm it spools out too much and then when it comes to pull in that direction it has to catch up with itself and loses accuracy. I redid calibration with a higher force and it seemed to make it less obvious, but the accuracy of my cuts are still low. I have been having retraction issues requiring high forces to pull the belts in so I am going to investigate what you mentioned regarding lubrication and spool tightness.
Edit: it just so happens that it was the bottom right spool and seemed to be worse when at a lower Z which is why I posted in this thread.
I think he might have had a typo. As in they weren¢t loose.
for future reference, videos of the problem help 
I¢m having the same problem. they aren¢t loose at calibration and then during
cutting, when moving away from said arm it spools out too much and then when
it comes to pull in that direction it has to catch up with itself and loses
accuracy.
That’s a classic case of a calibration problem, commonly a Z problem at the time
of calibration (either the anchors aren’t the right height, or you calibrate on
a thick material and then try to cut a thinner one, or the router wasn’t all the
way down when you did the calibration)
but it can also be just about any other calibration problem like I mentioned
earlier.
I redid calibration with a higher force and it seemed to make it
less obvious, but the accuracy of my cuts are still low. I have been having
retraction issues requiring high forces to pull the belts in so I am going to
investigate what you mentioned regarding lubrication and spool tightness.
that’s a pain to do, but a good idea
David Lang