Big problem with my stepper drive

[louieatienza]

I was cutting a sample out of phenolic when I started hearing a strange noise from the Y stepper. Basically, the Y stalled out, leaving the X to plow though, and actually cut through, a washer in one pass!

There were no obstructions on the table. I couldn't jog the Y, so I shut off the computer and reboot. Could jog the Y but it sounds like I'm getting stalling and shaking on the acceleration and deceleration. Went to motor tuning and tried lowering speed (I had it set at 400ipm) to 200ipm, then 100... It sounded worse, and under 50 it wouldn't move at all. Seems it runs rougher at lower speeds and lower accelerations. I still get holding torque, and X and Z move well. With the drive off (it's a xylotex) I can easily move the carriage on the Y very easily by turning the screw.

Potential culprits:
- Dust shorted the Y axis (though I still ger holding torque)
- Weird setting problem
- Problem with cables/connectors, though I checked each one
- Problem with stepper

I suppose I could swap cables and see if the problem persists. Any suggestions would be helpful. I have a nice large potential job hinging on this sample. Worse comes to worse, I'll have to set up the G540 box I got for the new machine, but the wires still need ot be made.

[ssutton]

Hate to hear that Louie, I would swap the motors/axis and see if the problem follows. You may have a bad motor and not a drive issue. I do not know your machine setup, but if I could run your sample for you I will if that would help you get out of a jam until you can get back up and running. PM me if you need me to help.

Scott

[TrickyCNC]

as above

the 1st thing I would do is swap the X and Y driver wires. Then you will know if it is the motor, or something before

If it is something before, and you have a separate BOB, then swap the feed from the BOB to the driver. Then you will know if it is the Driver, or before.

If it is still before, try using a spare axis on the BOB (if you have one) or set the BOB / Mach3 to use different pins on the par cable. Then you know if it';s the BOB or before

if before, then its down to the par cable, the par card/port , or software .

you get the idea ? ... just trace it back, step by step.

HTH

Rich

[lamesh99]

motor itself could be damaged. similar thing happened to me: a phase in the motor burned up, so i disassembled the motor, and found what appeared to be the problem: it has a small pcb for connections, and one of the traces on the pcb simply melted (like a fuse, sorta). so i soldered a piece of thin wire, repaired the break in trace, and tried the motor. at "high" speeds (450mm/min) it kinda spins, but at 50mm/min, it jitters and stalls a lot. luckily, the motors were altogether 20$/4pcs, so it's not a big deal. i would first try swapping out the motor, and then everything else. hope you work it out!

[ger21]

I would thing if the motor went bad, it would kill the Xylotex instantly.

Is there any chance the Xylotex is getting hot, or maybe the Y axis heatsink came loose?

[lamesh99]

I would thing if the motor went bad, it would kill the Xylotex instantly.

Is there any chance the Xylotex is getting hot, or maybe the Y axis heatsink came loose?

you're probably right, because when i tested the "repaired" motor, two out of four 9A mosfets burned out after a short while

[louieatienza]

Thanks everyone for the replies.

The board itself didn't feel hot. I blew out all the dust and underneath. The heatsink looks to be secure. The steppers never get hot, just warm even on all-night runs.

So I guess if I put the X lead to the Y motor and it works, then it's not the motor. And if I put the Y lead to the X motor and it works, then it's not the board.

A week or so ago, the vacuum hose slipped and jammed the Y against a fixture, and it took me about 15 seconds to run downstairs and hit the kill switch. I lost the part, but was able to make parts after with no problems.

My gut is telling me it's probably the board itself, but when I get back home I'll perform the tests to make sure.

In case I DO have to use the gecko box, since the current rating of the xylotex motors are 2.5A, this means I need a 2.5ohm resistor in the plug? Then if and when I replace the xylotex board, I'll just mod the case with DB9 connectors so I can mount the wires back...

[louieatienza]

OK the good news is that it is not my Y motor. Swapped the X lead in, and it ran smooth as silk. Running the Y lead into the X stepper made the same noises, like a jackhammer at low speeds.

The bad news is that I think the board is done. Checked everything to make sure there was no dust or swarf anywhere, but I think the damage is done....

So I guess I'll be using the Gecko after all. Just the same, this was a mod I planned to do to get a little more juice into the steppers. Still waiting from xylotex on a return email to purchase a new board; from the way the X and Z still work, I think the psu is still fine.

This gets me thinking if I should upgrade this machine to the G540, and maybe choose a different path with the new machine. I'll repurpose the xylotex if that happens.

[louieatienza]

I can't believe how tedious it is to solder the DB9 connectors for the Gecko. Not only are my eyes shot, I was shaking like I had withdrawals, and my fingers work like they have mitts on!

But glad to say, I'm up and running and holy cow! I can rapid over 800ipm setting the accel up over 50, but I'm afraid I'll melt the delrin nuts!

Jeff at xylotex has given me some troubleshooting ideas (thinks it's a rare malfunction of the phase thing...) and am waiting for a price on a replacement board. I'll repurpose the drive for a smaller machine, as I don't think I'm turning back! My cell is dead so no vids yet but Holy Crap! It's like living your life with a bag over your head, and someone pulls it off!

[CarveOne]

Snip

But glad to say, I'm up and running and holy cow! I can rapid over 800ipm setting the accel up over 50, but I'm afraid I'll melt the delrin nuts!

Snip

CarveOne

[louieatienza]

CarveOne

That's exactly what my face looked like rapiding around!

[crane550]

The Gecko is just a killer drive, no matter which way you slice it. Glad you found the problem! Perhaps you can get your old board working again and use it for another machine!

Alex