[gene8522]

I have a "Black Toe" style CNC with 1/4" chains on the 'x' & 'y' axes, every thing works, but when the 'x' stepper motor is running I get a jerking and clicking sound. I have checked all the fittings for tightness and they look to be OK. I have a gantry that is about 30" wide that has a 425 oz in stepper on the drive. I don't seem to be able to run the 'x' very fast before 'x' axes starts to shake. I am wondering if I should look into changing to a larger stepper, say maybe a 651 oz in stepper. Has anyone had trouble with the sizing on their steppers?

[ger21]

Sounds like a chain alignment issue maybe? You might want to ask on the buildyourcnc forum, as there aren't many chain drive users here.

[CarveOne]

Sounds like the chain may be tight enough that the motors can't overcome the cogging of the chain and sprocket and start trying to stall even at fairly low jog speeds. Adding cutting loads just makes the motors stall sooner.

Try loosening the chain tension a little and see if the condition stops. I would think that there is a fairly fine line between having enough tension to remove backlash, and the point that the chain starts to run "bumpy".

CarveOne

[gene8522]

I have been trying to diagnose my problem all day. Here's what I've done. I checked & rechecked the tightness of the shaft connections on the motors. Looked at the chains for alignment, even put grease on the sprockets and chains. But here is the only thing I have noticed. I need your experience with the stepper motors on this question. My motors (all three) do not have a smooth sound coming from them. I disconnected the coupling from the 'Z' motor, now when I run just the motor, fast or slow, I get a knocking, clicking noise. Not a smooth buzzing sound. Is this what I should be expected from the steppers? The videos I've seen do not have the sound I am getting. I have tried to change the velocity & acceleration with no or little change in the knocking, clicking. The sound reminds of a gear box with some teeth broken. Does this make sense?

[ger21]

Sounds like something in the PC may be interfering with the pulses, but it's really hard to diagnose, as it could be any number of things.

Are you using Mach3?

[gene8522]

Sounds like something in the PC may be interfering with the pulses, but it's really hard to diagnose, as it could be any number of things.

Are you using Mach3?

Yes I am..............

[Craigeee]

Hi there does the motor run smooth with power off if u turn it by hand, you should be able to turn by hand just feeling the magnetic fields as u rotate, I had a problem simular to this and found the motor was catching inside so I took apart and reassembled cleaning inside with tiny amount of oil and is now perfect
Compare the feel as u rotate with a known working motor use a working motor to relate to hope this solves the problem.


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I am here: http://maps.google.com/maps?ll=53.363726,-3.000153

[gene8522]

The motor feels OK with the power off. But I don't have a known good motor to compare.

[CarveOne]

Is the sprocket mounted directly onto the step motor shaft?

If yes, the tension on the chain will quickly destroy the shaft bearings in the motor. The sprocket should be mounted to a shaft that is fully supported and a coupler of some sort used to connect the motor shaft to the sprocket shaft. Chain tension should never be directly applied to the motor shaft in any direction.

When you rotate the motor shaft by hand and you feel (or can hear) the armature hitting the magnets the motor is damaged. You should only feel the magnetic detents with no solid collisions. Everything I have read about step motors says never take them apart, as the torque will be significantly reduced after reassembly. Do it only if you want to see what's inside of a known bad one, or see if you can salvage the magnets for other fun projects.

CarveOne

[gene8522]

I would like to thank everyone for the come back.

This came ger21
>>Sounds like something in the PC may be interfering with the pulses, but it's really hard to diagnose, as it could be any number of things.

Are you using Mach3?<<

This got me to thinking "something in the PC" , what other that the Mach3 software. So I downloaded the new Mach3 - 3.043.022 to a flash drive (was using 3.042.040) and took it to my shop and ran it on my PC.
Well gress what all steppers are as smooth as can be. I tried runing the 3.042.040 again and after a little bit the steppers starting making that noise again. So out with the 'old' in with the 'new'. Well go figure.............:cheers:

[CarveOne]

That's good to hear. It's a known issue and Gerry had already mentioned it so I ranted on about potential hardware issues that it might be related to. I looked at the Black Toe site before building my first machine and went with a lead screw machine.

CarveOne

[gene8522]

>>>>> Originally Posted by ger21
"Sounds like something in the PC may be interfering with the pulses, but it's really hard to diagnose, as it could be any number of things." <<<<<

This started me to thinking about a software problem or PC and not the chain drive or steppers. After many e-mails back and forth with Scott @ Mach3 & Gerry @ Mach3 2010 Screenset. They helped me idenify my problem. Gerry suggested I check my bios for "EIST" and 'Disable' it if it were 'Enabled'.


This is a copy of an e-mail I sent to Gerry @ Mach3 2010 Screenset. Turns out I'm sure my problem all this time has been with my PC. I have a Pentium Dual Core 2.13 GHz 32 bit and the problem was in the bios settings. I would have never known to look at the bios without Gerry's help. I hope this will help someone else...................
"Well some good news!!!!……………… I installed Mach3 2010 Screenset into Mach3 and ran Mach3 with and without g-code loaded. I was not getting noise from the steppers until I loaded in the g-code. With g-code running I was getting a defiant noise from the steppers. I shut everything down and opened my bios and found the settings for EIST were ‘Enabled’, so I “Disabled’ EIST and started everything back up. Without G-code loaded everything was nice and smooth, BUT with g-code running the old noise had gone away. As a double check I went back into the bios, ‘Enabled’ EIST and the noise returned. So I’m sure there is something going on with the Pentium Dual Core processer.
Thanks for your help without it I would be in my shop with the chainsaw close at hand looking for the fuel can. This problem has been going on ever sense I build my “Blacktoe”. Buy when I think back it got worse when I started using Mach3 2010 Screenset. When I first built the CNC using just Mach3 I would get a knocking & jerking if I did a fast jog in the ‘X’ move and sometimes in a ‘Y’ jog. The only way to control it was to run the steppers very slow. Here lately, sometimes the tool path would be off from where it should be and I would have to do a recut or a lot of sanding. I bet, now I could turn the speed up and everything would run smooth.
Thanks again,
Gene"gene8522