Problem- Stepper stutter issues resolved

[pencilneck]

Finally get the CNC mill project up and running and I started to have a stuttering issue with the stepper motors. 2 things I found that I think are the source...

I purchased my steppers, power supply, Gecko G540 and cables from CNCRouterParts (along with several other goodies, great customer service).

With the current demands being placed on the DB9 cables, the male pins on the stepper motor were getting too hot:



The bottom 4 pins are the only ones that went to the stepper motor, they are deformed at the tips and burnt up some. This caused the plastic that they are pushed though to soften up so when I had unplugged and replugged, a pin got pushed back. This happen to all 3 plugs. I cut the ends off and used Molex connectors:



With that, the issue was improved but there would be times where I'd hear one of the stepper motors buzzing loudly, twitching and I couldn't jog it. Happened mostly to the Z axis. I found that I unplugged the power supply for a few minutes then plug back up, everything would work normal for a little while. Then I found just blowing compressed air on the bottom of the G540 the buzzing noise would stop on it's own and work again for a short time.

The bottom of the G540 would get VERY hot. I've seen a fan kit that mounts to the bottom. Based on that simple concept, I decided to make use of some desktop power supplies that were given to me.

Gut them for the needed parts:



Break out the zizzzzz wheel and do some cutting:



Figure out my spacing needs, trim a little more, bend and drill and I've got simple brackets:



Mount onto the ye' old TV stand to keep the G540 cool:





Note, I had to mount the cooling fans the opposite direction they were originally mounted so that they would blow air onto the G540. They are getting power from the desktop computer I'm running ECM2 on, just out of frame.

Did a dry test run so that the mill ran for over 1 hour, then ramped up the jog speed some just went back and forth with the mill. The G540 was barely warm and at no time did I have any stepper stutter.

Posting this up for the next newbie who runs into the same issue like I did, save them some hair pulling.

PS - yes yes, that is a very crappy wiring job you see there. Still in the testing stages. Hope to mount everything inside a large desktop tower case and neaten up the wiring mess shown.

[PaulRowntree]

Good to hear that you beat this one. There is a good document on the Gecko site that covers the temperature control of the G540.

https://www.geckodrive.com/upload/G5...Experiment.pdf

Readers Digest Version : Get a fan (as you discovered!)

I wonder if the problem isn't made worse by mounting the G540 onto a thermally insulating wooden board. The heat generated by the G540 MOSFETs has nowhere to go. Metal cabinet mounts function as heat sinks.

[CarveOne]

Originally Posted by PaulRowntree Good to hear that you beat this one. There is a good document on the Gecko site that covers the temperature control of the G540. https://www.geckodrive.com/upload/G5...Experiment.pdf Readers Digest Version : Get a fan (as you discovered!) I wonder if the problem isn't made worse by mounting the G540 onto a thermally insulating wooden board. The heat generated by the G540 MOSFETs has nowhere to go. Metal cabinet mounts function as heat sinks.

Mounting the G540 directly onto a wood board is definitely a bad idea. Mount it to a heat sink of some kind using thermal grease between them, mount the heatsink to the board with something like 1/2" long aluminum spacers, and cool the whole assembly with a fan. The cooler it runs the longer it will last.

CarveOne