I am having a world of problems with my CNC trying to get it calibrated. After working through other issues, I finally got it to start the calibration process. I have my grid set to 9x9 with a dimension of 2000 wide x 1000 tall. The calibration process starts, reads 8-9 points within a 500 x 500 area, stops to calculates, then says something like “unable to calculate belt lengths, locked out” (not exact wording but same idea). Any help would be appreciated. I used steel struts and had to extend them to get 12 feet so they are offset and the anchor points are not a square shape; wondering if this is the problem… See image below. I can copy the serial messages if needed.
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please post the exact error messages that you see.
One thing that I am seeing is that your anchors are higher compared to the base
of the sled than the default config specifies. This isn’t a bad thing for your
eventual accuracy, but could be part of your calibration issues. Change the
Maslow_xxZ variables in your config to match your actual offsets (since unistrut
is 1 5/8 IIRC that will mean reducing them by ~42mm each, more if there are
washers between the unistrut and the anchor, and probably another ~20mm as you
are calibrating on the wasteboard, not on a workpiece on top of the wasteboard)
David Lang
$/Maslow_vertical=true
$/Maslow_calibration_grid_width_mm_X=2000.000
$/Maslow_calibration_grid_height_mm_Y=1000.000
$/Maslow_calibration_grid_size=9
$/Maslow_Retract_Current_Threshold=1300
$/Maslow_trX=3600.000
$/Maslow_trY=2300.000
$/Maslow_Acceptable_Calibration_Threshold=0.450
$/Maslow_tlX=0.000
$/Maslow_tlY=2300.000
[MSG:INFO: Caution: Unlocked]
[MSG:INFO: Retracting all belts]
[MSG:INFO: Bottom Left pulled tight with offset 0.000]
[MSG:INFO: Bottom Right pulled tight with offset -409.625]
[MSG:INFO: Top Left pulled tight with offset -1998.662]
[MSG:INFO: Top Right pulled tight with offset -1992.725]
[MSG:INFO: Extending all belts]
[MSG:INFO: All belts extended to center position]
[MSG:INFO: Setting z-stop position]
[MSG:INFO: Measured waypoint 0]
[MSG:INFO: Center point deviation: TL: 0.230 TR: 0.385 BL: 2.658 BR: 60.850]
[MSG:INFO: Measured waypoint 1]
[MSG:INFO: Measured waypoint 2]
[MSG:INFO: Measured waypoint 3]
[MSG:INFO: Measured waypoint 4]
[MSG:INFO: Measured waypoint 5]
[MSG:INFO: Measured waypoint 6]
[MSG:INFO: Measured waypoint 7]
[MSG:INFO: Measured waypoint 8]
CLBM:[{bl:2138.66, br:2196.85, tr:2136.39, tl:2136.23},{bl:2073.32, br:2132.20, tr:2206.09, tl:2206.00},{bl:1861.58, br:2350.24, tr:2414.49, tl:2007.19},{bl:1937.53, br:2409.88, tr:2350.76, tl:1930.22},{bl:2017.84, br:2474.68, tr:2292.22, tl:1858.53},{bl:2212.78, br:2267.23, tr:2071.75, tl:2071.70},{bl:2415.02, br:2069.58, tr:1858.75, tl:2292.22},{bl:2349.06, br:1992.47, tr:1930.45, tl:2350.68},{bl:2288.46, br:1919.23, tr:2007.36, tl:2414.27},]
Computing… This may take several minutesFitness: 0.2163292 in 100
Fitness: 0.9551800 in 200
Fitness: 1.8296959 in 300
Fitness: 2.0707891 in 400
Fitness: 2.4292129 in 500
Fitness: 2.4505501 in 600
Fitness: 2.4710242 in 700
Fitness: 2.5063708 in 800
Fitness: 2.5077593 in 900
Fitness: 2.5077593 in 1000
Fitness: 2.5077593 in 1100
Fitness: 2.5077593 in 1200
Fitness: 2.5077593 in 1300
Fitness: 2.5077593 in 1400
Fitness: 2.5077593 in 1500
Fitness: 2.5077593 in 1600
Fitness: 2.5077593 in 1700
Fitness: 2.5077593 in 1800
Calibration complete
Calibration values:
Fitness: 2.5077596352513765
Maslow_tlX: -28.4
Maslow_tlY: 2304.0
Maslow_trX: 3605.5
Maslow_trY: 2297.0
Maslow_blX: -28.4
Maslow_blY: 2304.0
Maslow_brX: 3605.5
Maslow_brY: 2297.0
A command to save these values has been successfully sent for you. Please check for any error messages.
[MSG:INFO: Setting z-stop position]
[MSG:ERR: Unable to move safely, stopping calibration]
[MSG:ERR: Emergency stop! Stopping all motors]
[MSG:WARN: The machine will not respond until turned off and back on again]
[MSG:ERR: Unable to move safely, stopping calibration]
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We accidentally let a bug slip into 0.86 which causes this exact issue. Updating to 0.87 should fix it. The most important part of the update is to update the index.html.gz file. That has the fix in it.
I’m really sorry for the trouble! I am going to work on testing changes more carefully in the future before merging them so it won’t happen again!
That was it, thanks Bar! I ran calibration after updating and a low memory error popped up after point 29 so I turned it off and tried again and I finally have a successful calibration.
One thing I noticed is that one of my motors/belts is making a creaking noise. Such as “creak, creak, creak, pause 2 seconds, repeat”. I noticed this prior and took the belt assembly apart yesterday (to verify I had it correct)and reassembled it only to have the noise again. Have you heard of any users having this issue before with any suggested fixes?
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This one is safe to ignore, but I’m working on a fix for that right now 
Yes! I’ve seen it myself. It’s the idler gear (the metal gear that isn’t on the motor) and the idler shaft rubbing. You can safely ignore it (what I’ve been doing), you can lubricate it, OR you can replace it with the 4.1 update which adds bearings there to get rid of exactly that issue.
EZ CNC Designs wrote:
One thing I noticed is that one of my motors/belts is making a creaking noise.
Such as “creak, creak, creak, pause 2 seconds, repeat”. I noticed this prior
and took the belt assembly apart yesterday (to verify I had it correct)and
reassembled it only to have the noise again. Have you heard of any users
having this issue before with any suggested fixes?
This could be a need for lubrication or it could be that some of the bolts
holding the arm together are too tight.
David Lang
Thanks for the insight Bar! I hope you know how amazing you are for taking on this project.
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We’re doing our best!
Bar wrote:
We accidentally let a bug slip into 0.86 which causes this exact issue. Updating to 0.87 should fix it. The most important part of the update is to update the index.html.gz file. That has the fix in it.
I¢m really sorry for the trouble! I am going to work on testing changes more carefully in the future before merging them so it won¢t happen again!
While nothing can completely eliminate doing a full test, what can we do to be
able to setup a test that can be run without the machine on a frame (and
ideally, without needing a spindle and full sled)?
David Lang
I think it would be pretty impossible to simulate. It’s a very complicated closed loop system with a lot of interacting parts 
As someone who is doing literally my 20th or so calibration of the day while testing I really wish there was a way
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How have you found your frame?
I already have a load of unistrut so no way I’m not going to use it when my Maslow arrives.
I cannot speak fully on it as I am yet to run a cut cycle (still working through some technical issues). I find them to be very ridged so far. In reading the how to by Maslow, they say that they don’t recommend them. I tried 3d printing the t-brackets that they use and was not a fan of them. Unless they are printed with 100% infill, they crush when bolted and they allow the frame to flex. I designed a coupler that allows the frame to be bolted directly together with minimal 3d printed parts. I was planning on posting about it once I get my CNC up and running. If you get your CNC before then, I could share the print file with you.
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