I’ve spent the last 2 weeks rebuilding my 10’ x 7’6" table, raising anchors and sanding the spools to the point that after a rebuild “retract all” works with a force of 600. Doing a cut in 18mm ply over the full 8x4 area, the first pass looked very good. The second cut had some approximations and the machine stopped with a position error after the second pass. This fault condition reliably causes V1.20 to lose connection and reboot, by the way. Having rebooted I tried to retract all to reset the cut.
One spool still worked at 600 retraction. Two more needed up to 1200. I stopped trying to retract the final one at 2200 and took it apart.
Taking off all the gears with the top housing and motor I was left with just the lower portion, spool and housing. The spool was stuck really tightly so it could not rotate, but moving it away from the housing brought it back to free motion. Has anyone else experienced this even when the spool is normally free? Is there a known fix, e.g sanding the internal corners between the bearing surface of the spool and the top and bottom faces?
The spool that locked was under the most load at the time of failure - horizontal motion at the bottom of the (horizontally mounted) sheet towards the bottom left.
If the bolts holding the spool together are too tight it can cause the plastic to bulge slightly which can cause the spool to bind. You can feel the slight bump with your fingers. Sand it out is the answer.
I’m facing this same issue. I removed the motor first and tried pulling out the belt - it was so tight I could barely get it to move. Taking the spool apart entirely, there was lots of plastic dust between the parts. I noticed that where the belt is super-glued in, it was sticking up ~1mm above the top of the plastic. Seems like when that gets squeezed, the rubber belt may be getting stuck between the plastic surfaces and causing them to bind.
Unfortunately the belt doesn’t respond great to sanding - it got hairs on the edge of the bumps that won’t come off. I’m hoping that overall sanding the plastic, maybe some PTFE lubrication, and backing off spool bolt tension a bit will help on the rebuild.
I’d also suggest you buy some spare belts, they come with a new spool which is slightly larger and doesn’t bind as much. I think the belts are going to be a consumable over time, and you don’t want to have to wait if one tangles or breaks. Having said that I have only had one break out of the spool in the early days when the Maslow headed for the hills, until it ran out of belt.
I have a spare belt and spool, but it arrived quite early in my Maslow 4 career, and the spool looks just like the originals. Are the new ones truly better?
I haven’t had to replace one since, but reports suggest they are. Still have to be careful not to overtighten screws, and a slightly longer screw is recommended.
I haven’t been able to keep myself updated on the newest firmware changes, so I am still running version 1.09 since it’s been working.
But I just experienced the same with one of the spools. I have the original M4.
A few days ago I started getting errors about reaching threshold for Top Right motor. This led to emergency stop with “15mm off” error.
A few cuts was a little off, but the parts were still usable for our needs. The errors only occurred in the top right corner, and only in one direction. Retraction force at time of failure was 1400.
I disassembled the arms and cleaned everything, but didn’t find anything that seemed to cause the issue. I changed the belt guards (new design) as the material they were printed with was brittle.
Unfortunately I got the same error at the same spot again. This time the spool was totally stuck after splitting the arm. I went on with sanding the spools and checking everything again. Fastened the screws loosely with lock tite.
Then I measured the current while fully extending and retracting the belts on every motor after assembling the arms. I did this before assembling the arms to the sled to have the same conditions. I connected the motors directly to 12V through the amp meter. Extending the belts was a steady 2.5-2.6mA. Retracting showed a top of 3-4 mA with no load.
I have Teflon sheets between all the spools.
I switched the top left and top right arms when assembling in case the error followed the same arm.
I extended all belts the full 4,2 meters. All the belts except the top left retracted with 700 force. With 900 it went fine.
Continuing the job(with 900 force) led to one error in the top left corner with a warning about threshold on the bottom right motor, and the cut was a little off, but it did not fail on the first pass. Failure at the same spot occured on the way back with the same warning for bottom right motor.
After taking down the Armadillo I extended all belts fully again and experienced the same when retracting at 700 up to 1000. Top left did not even start pulling before 1100. Measured current was never above 4mA.
Could this be a hardware issue?
I was planning to update firmware after doing this cut since it seems to be a little iffy when jogging the Z axis.
Tore Westre wrote:
A few cuts was a little off, but the parts were still usable for our needs.
The errors only occurred in the top right corner, and only in one direction.
the arm in that direction would be the suspect one
Retraction force at time of failure was 1400.
retraction force does not matter when cutting, only when calibrating and
retracting (so it knows how hard to pull before stopping
I disassembled the arms and cleaned everything, but didn’t find anything that
seemed to cause the issue. I changed the belt guards (new design) as the
material they were printed with was brittle.Unfortunately I got the same error at the same spot again. This time the spool
was totally stuck after splitting the arm. I went on with sanding the spools
and checking everything again. Fastened the screws loosely with lock tite.Then I measured the current while fully extending and retracting the belts on
every motor after assembling the arms. I did this before assembling the arms
to the sled to have the same conditions. I connected the motors directly to
12V through the amp meter. Extending the belts was a steady 2.5-2.6mA.
Retracting showed a top of 3-4 mA with no load.I have Teflon sheets between all the spools.
I switched the top left and top right arms when assembling in case the error followed the same arm.
I extended all belts the full 4,2 meters. All the belts except the top left retracted with 700 force. With 900 it went fine.
Continuing the job(with 900 force) led to one error in the top left corner
with a warning about threshold on the bottom right motor, and the cut was a
little off, but it did not fail on the first pass. Failure at the same spot
occured on the way back with the same warning for bottom right motor.
After taking down the Armadillo I extended all belts fully again and
experienced the same when retracting at 700 up to 1000. Top left did not even
start pulling before 1100. Measured current was never above 4mA.Could this be a hardware issue?
Yes, this is clearly a hardware issue, you found one spool that didn’t turn, did
you check it against both sides of the arm? did you add lubrication when you
reassembled it? check that the idler spins freely (no plastic dust getting in
it) and that the gear on the motor isn’t rubbing.
This sort of degredation usually means that something is grinding a bit of
plastic dust and it’s getting into the works and causing it to jam up. I know
exactly how big a pain it is to take it apart again. if you have the belt
extended a little bit so that it isn’t pulled tight, you should be able to
wiggle the spool a bit and see which ones move freely (just through the gear
backlash) and which ones are really stiff.
David Lang
retraction force does not matter when cutting
I might have misunderstood one of the above post regarding “motors pulling too hard against each other”.
I was thinking more controller/encoder issue when I wrote hardware, but I suppose that would have given more consistent error messages.
I’ve taken them apart 3 times the last week 
. The spools were all cleaned and lubricated with a small amount of silicon grease and tested before putting them back on the spindle. Last time I sanded them a little and made sure the bolts weren’t tightened more than needed. All spools and gears spun freely before attaching motors, and all idlers were loose enough to glide easily off without “wiggle room” after attaching motors.
I have noticed that the belts have signs of wear on the edges. As in “not as slick along the sides”, so it might be that this belt gets pinched a little in some places because of this. That’s the only thing I haven’t managed to fix as I’m not sure sanding the belts is a good idea?
I have ordered new belts. Not original belts, but I found the same dimension of steel reinforced belts a little cheaper in regards to shipping costs. I might order the new spools with belts anyway if I can’t get the new 4.1 spool models machined or 3D printed in sufficient quality.
I’ll see if I manage to wiggle them a little as you mentioned.
Thanks David!