I have a belt that's losing tension

My machine operates in a vertical position, and when it’s moving to the right (especially from the middle of the table upward), the lower left belt (BL) loses tension. However, when that motor is needed to control the machine, it works fine. Large cuts aren’t a problem, but when I want to do small details or work at higher speeds, errors occur because it can’t compensate for that lack of tension.

I haven’t been able to calibrate it automatically; I’ve been working with manual measurements for a while now. I’m setting the retraction force to 600, and generally the belts all retract properly, and the anchors don’t seem to move.

I think there could be several possible causes:

- The height of the BL anchor may have been measured incorrectly.

- The overall frame dimensions may be incorrect.

- The opposite motor (TR) may be overloaded.

- There may be issues with the BL spool.

- My frame may be warped.

- …

Is there a logical approach I can follow to find a solution without having to take all the measurements again and take the whole machine apart?

Any ideas that might guide me on the next step?

Maslow-serial revision BL.log.txt (34.6 KB)

Javier Betancourt wrote:

My machine operates in a vertical position, and when it¢s moving to the right
(especially from the middle of the table upward), the lower left belt (BL)
loses tension. However, when that motor is needed to control the machine, it
works fine. Large cuts aren¢t a problem, but when I want to do small details
or work at higher speeds, errors occur because it can¢t compensate for that
lack of tension.

This is a classic symptom of the anchor coordiantes not being quite right (it
could be X Y or Z coordinates)

I haven¢t been able to calibrate it automatically; I¢ve been working with
manual measurements for a while now. I¢m setting the retraction force to 600,
and generally the belts all retract properly, and the anchors don¢t seem to
move.

I think there could be several possible causes:

- The height of the BL anchor may have been measured incorrectly.

- The overall frame dimensions may be incorrect.

more likely one of these

the flatter the belts, the less an error in the anchor heights will matter. the
problem is not necessarily in the BL anchor, it could be in other anchor
coordinates

- The opposite motor (TR) may be overloaded.

this would generate log messages about excessive current. but you can test this
by just setting your feed rate lower and see if that solves the problem

- There may be issues with the BL spool.

not likely, not if you can retract reliably with 600

- My frame may be warped.

this is a variation of coordinates being wrong :slight_smile:

- …

Is there a logical approach I can follow to find a solution without having to take all the measurements again and take the whole machine apart?

Any ideas that might guide me on the next step?

Maslow-serial revision BL.log.txt (34.6 KB)

this is very useful, two errors in here that matter

[MSG:ERR: MaslowKinematics: Failed to compute X,Y from belt lengths, using (0,0)]

This is saying that the anchor locations + belt lengths do not compute to a
valid location

this seems to go away after you apply tension

error:9

This is saying that the UI tried to issue a command or fetch data from the
firmware and the firmware refused. it’s possible that this is an error during
jogging, or it could be that your index.html.gz file doesn’t match your
firmware.bin

or it could be something missing in your maslow.yaml file

these continue to happen. it’s possible that this is happenign because you hit
something while it’s busy jogging, so it rejects the command, or it could be
something else. I would make sure I have the anchor locations recorded and then
replace the maslow.yaml

you are on 1.20 for both index and firmware, that’s only one rev back from the
released version

David Lang

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You can also manually measure the anchor points with tape measure and verify the values in yaml are reasonable as well. That’s more for your on piece of mind. Somewhere there is a web tool to help take your measurements and give the anchor locations.

Dano

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Dano wrote:

You can also manually measure the anchor points with tape measure and verify
the values in yaml are reasonable as well. That’s more for your on piece of
mind. Somewhere there is a web tool to help take your measurements and give
the anchor locations.

there are a few, I have one in onshape at

David Lang

1 Like