Z axis movment mid layer

[brentlymills]

Hello,

I am posting this because I want to verify that the behavior i am seeing is due to the z axis stepper motor and not the RAMBo.

This just started last night during a 10 hour print. The z stepper would drop a bit (a fraction of a layer height) in the middle of layer as if there was a command to lower the z height. My hunch is the z-stepper is dying -- but I am curious if others have seen this behavior.

I have checked all connections the the RAMBo and the machine is well lubricated and maintained.

I am running a 1st generation M2 with the 24V upgrade and a v3b 0.25mm hotend.

Any advice is very much appreciated.
Thank you,
Brent

[Vandal968]

Much more likely to be the stepper driver than the stepper itself (never had one fail). Stick a heatsink on the z-axis stepper and see if anything improves. I buy these kits all the time:
http://www.ebay.com/itm/321525213559?_t ... EBIDX%3AIT

The small size is perfect for the stepper motor drivers on the Rambo and the large size is good for anything bigger. I used one on the hottest chip of my cable-modem which used to need to be rebooted daily and it hasn't had a hiccup in two months.

cheers,
c

[Tim]

On the contrary---it is more likely the stepper motor than the stepper driver. The key is that this thing is a first generation M2 with a 24V upgrade. The Z steppers on early models have a high resistance, run very hot, and upgrading to 24V seems to deliver a quick death. That's exactly what happened to mine. See if you can get a replacement stepper motor from MakerGear. Unfortunately there's not much other solution; your motor is dying and there's not much you can do about it. On the positive side, once you get a new motor with the correct winding resistance, it will run cool and live a normal motor lifespan.

[brentlymills]

Thank you very much for the response. If it is the driver then I suspect the driver itself is nearing the end of its life. I have run my M2 for 2 years with very heavy usage and have never encountered this behavior until now. I'll slap a heat sink on the z driver and hope that it improves.

Thank you,
Brent

[brentlymills]

On the contrary---it is more likely the stepper motor than the stepper driver. The key is that this thing is a first generation M2 with a 24V upgrade. The Z steppers on early models have a high resistance, run very hot, and upgrading to 24V seems to deliver a quick death. That's exactly what happened to mine. See if you can get a replacement stepper motor from MakerGear. Unfortunately there's not much other solution; your motor is dying and there's not much you can do about it. On the positive side, once you get a new motor with the correct winding resistance, it will run cool and live a normal motor lifespan.

Thank you Tim for the response!

Yeah that sounds like it. I was wondering when and if I'd encounter any issues upgrading to 24v. At least the motor is cheaper then the controller