Loses tension after jogging at all

Troubleshooting
1

I was finally able to do my first cut, and I noticed that the bottom right belt wasn’t tight. It was loose enough that I could wiggle the rotating arm about an inch, but seemed to feed and retract correctly.

I just took it apart to replace a broken belt, and added new belt guards to all the spools while I was at it, so I’m not sure if this is the same spool. One of the plastic gear rollers on that spool looked slightly damaged, so that might be the culprit.

I pressed the apply tension button, and all the belts were taut, but the bottom right loosened again after a 10 cm jog.

It was late, so I didn’t do much troubleshoot yet… Are there any firmware settings or troubleshooting I should do before taking it apart again?

The cut actually came out fine, but it was an etching about 1 mm deep to test the detail work I’m hoping to do. I’m worried about the lack of tension for a cut with more torque, though.

2

do a couple cycles of extend all/retract all and look at the numbers at the end
of retraction, they should all be near zero, if they aren’t, you need to
increase retraction and calibration current.

Then you will need to do calibration again and make sure that the belts are
getting tight at every point that’s measured (and after the first couple of
points, they should be pretty tight as you are moving.

make sure that the Z axis is all the way down when you do the calibration.

David Lang

3

Another thing I like to do when I notice some slack in the belts is to reset the Z stop. The machine does some math that takes its position on the z axis into account, but if it lost track of where it is vertically, the math may be slightly off resulting in some sloppy belts.

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4

Running calibration again can also fix this, it could just be a funky calibration value

5

So, it’s not normal for one of the belts to be slack when working at the corners of the work area?

I ran out the entire spool and retracted it with tension. Then, I ran the calibration a few times, and it came up with very similar values, but the bottom right belt was still pretty loose when working in the top left quadrant (about an inch of play when the bottom right belt was out 75 in). I manually decreased the bottom right x coordinate by 3 mm, and this got rid of the slack. But after this, the bottom left has slack when working in the top left area.

I measured across the spoilboard, and it looks like the calibration is correct to within 1/16 in.

Should I just run the calibration a few more times? I’m not sure if the starting point is the values in the setup panel or in the configuration settings.

My current plan is to measure the z offset, and update the yaml, since I think it’s off by 5 or 10 mm.

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6

We would like for all four belts to be tight at all times.

Keeping all four belts fully tight all the time is tricky though because it requires PERFECT calibration because system is over defined (ie any three belts define the position) and that is especially true in the extreme corners of the frame. If you are getting good cuts and one belt is slightly lose in the far corners don’t let that stop you from making things…but we are working to keep making it better.

7

Alex S wrote:

So, it’s not normal for one of the belts to be slack when working at the corners of the work area?

Should I just run the calibration a few more times? I¢m not sure if the starting point is the values in the setup panel or in the configuration settings.

no, it is not good for one of the belts to get slack.

However, what you may be running into in the corners is the arms hitting the
frame. When you are in the top left corner of the workpiece, the belt/arm to the
top right and bottom left may hit the frame (making those belts effectively a
litttle shorter than they should be). At that point, the top left, top
right, and bottom left belts will be under increased tension with each other
(stretching and/or flexing the frame) and the bottom right belt would get some
slack in it because the sled is not as far into the corner as it should be.

This is not a linear problem (i.e. it’s not that if you are 10mm into the area
you have X amount of problem and 20mm in you have 2X the problem), it’s the
effect of trig angles, so very small initially, but past some point the rate of
increase of error increases significantly.

If you have hoses/cables preventing the sled from rotating, it can run into this
sort of problem earlier.

What is your frame and workpiece size? I have a calculator that shows this at
http://lang.hm/maslow/maslow4_frame.html the white area is where the effect I
describe above is happening (the red area is where adjacent belts/arms hit the
frame)

David Lang

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8

Ah, that makes sense. The frame is roughly 8ft by 8 ft (92.5 x 94.5), and I have a 4 ft by 6 ft spoilboard. Going by your calculator, I should probably only calibrate with a 3.5 ft square area in the center. I’ll give that a try and see what happens.

Thanks for the input!

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9

Alex S wrote:

Ah, that makes sense. The frame is roughly 8ft by 8 ft (92.5 x 94.5), and I
have a 4 ft by 6 ft spoilboard. Going by your calculator, I should probably
only calibrate with a 3.5 ft square area in the center. I’ll give that a try
and see what happens.

going a little into the red/white area isn’t fatal, so you can probably cut in a
4x4 area, but I would limit the calibration to the 3.5x3.5 area

David Lang

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10

I’ve been meaning to post an update in case it helps anyone else out…

The calibration process never worked for me, no matter the area that I used. The bottom right belt would always be loose after jogging the machine. I made a spreadsheet to display the combined error of all the points from the calibration, and manually adjusted the points until they seemed right in the center.

Then I jogged the machine to each of the corners to see where there were loose belts, adjusted the corners in the firmware, then repeated. I used a guitar tuner to check the tension at different points for a final run through (37 hz for top belts and 30 hz for bottom belts on an 8 x 8 frame in the vertical orientation, if anyone is curious).

The only issue I’ve found is that when the machine is in the top right corner, the bottom left belt will go slack if it’s not moving. When I jog from there, the belt will tighten before moving. Is that an issue or as designed?

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11

I just had this exact same issue on the BL, surprised I didn’t see this thread when searching.

I was able to solve it by deleting the Maslow.yaml file on the machine, uploading a fresh one, and calibrating again. The problem came back on BR after the machine crashed, so I tried it again but updated my calibration numbers in the file before uploading and it fixed the issue again.

Check my thread for a video and details: Belts become loose on any axis movement - #30 by kyleschoen

Hope this works for you!

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12

Hola, he estado siguiendo estos hilos ya que tengo el mismo problema, BR pierde tensión en el trote, sigo los pasos que han descrito, ajustar marco, puntos de anclaje, borrar el archivo .yamln, pegamento caliente, aire comprimido… he tenido que trabajar solo en el centro del area de trabajo, pues en los lados hace un efecto almohada y en algún punto del trabajo se desubica y daña los cortes que ha hecho moviéndose hasta 4 milímetros, ya les mostraré fotos de lo que he logrado hacer y de los errores, mientras tanto quiero preguntar, a que te refieres con actualizar los números de calibración en el archivo antes de cargarlo?[quote=“kyleschoen, post:11, topic:22015”]
The problem came back on BR after the machine crashed, so I tried it again but updated my calibration numbers in the file before uploading and it fixed the issue again.
[/quote]
P:D:quiero hacer esto antes de desarmar la maquina y revisar el imán, también tengo pensado cambiar el kit JST, pero estoy en Colombia y comprar en dólares es casi un lujo. Adjunto traducción de google, pues no hablo inglés, esto ha sido otra parte de mi desafío con este mundo CNC, agradecido con esta comunidad por que siempre están dispuestos a ayudar y enamorado de la ingeniería de Maslow

Traducción por google
Hi, I’ve been following these threads as I have the same problem, BR loses tension in the jog, I follow the steps you’ve described, adjust frame, anchor points, delete the.yamln file, hot glue, compressed air… I have had to work only in the center of the work area, because on the sides it makes a pillow effect and at some point of the work it gets out of place and damages the cuts it has made moving up to 4 millimeters, I will show you photos of what I have managed to do and the mistakes, in the meantime I want to ask, What do you mean by updating the calibration numbers in the file before uploading it? [quote=“kyleschoen, post:11, topic:22015”] The problem came back on BR after the machine crashed, so I tried it again but updated my calibration numbers in the file before uploading and it fixed the issue again. [/quote]
P:S: I want to do this before disassembling the machine and checking the magnet, I also plan to change the JST kit, but I’m in Colombia and buying in dollars is almost a luxury. I attach google translation, because I don’t speak English, this has been another part of my challenge with this CNC world, grateful to this community because they are always willing to help and in love with Maslow’s engineering

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