I’m looking for some guidance - at least once per job, my Y axis stalls after aligning the part over the camera while travelling to the placement location. There’s a grinding noise and the machine loses home. I can stop the job and rehome the machine and it works fine until it decides to stall again. When it stalls it seems to be trying to move a lot faster than normal ( like it’s ignoring the limits).
What should the current be set to on the y stepper driver, and is this a known issue? Thanks!
Hi,
This may appear to be a drive failure, but it could also stem from some motherboard anomaly.
First, attempt to locate the source of the fault:
Thanks Leo.
It’s definitely not trying to go beyond the Y limit – the problem happens when the head is pretty much in the middle of the range of motion – directly over the center of the machine. It doesn’t seem to be overcorrecting (it’s placing 0603 parts) but I’ll make sure to watch the logs for huge deltas.
There are also no electrical issues – all controller LEDs are lit, and everything else seems to be working.
Setting the overall speed to 75% seems to provide more reliable operation.
I can’t find any documentation regarding the proper settings for motion in OpenPNP, and the current settings for each of the drivers. Can you provide the OpenPNP defaults and current settings for each axis so I can compare - and so I can try a different stepper controller?
I’m running the very latest firmware as posted in the download section, on a V3 motherboard – FYI: homing the machine is rock solid now THANKS.
The stalling problem also happened when running the previous version of firmware.
Setting the overall speed to 75% seems to provide more reliable operation.
One source of instability in stepper drivers can stem from heat generation: after running for a period, the driver chip’s temperature rises, causing actual drive capability to decrease or even resulting in missed steps.
Are you using a Y-axis driver with an aluminum heat sink?
Reducing speed can lower heat generation and thereby slightly prevent this issue.
Machine Setup > Axes > Y
Try lowering the Feed Rate and Acceleration.
Alternatively, enhance heat dissipation or lower the current setting. For the Y-axis, the current can be set to approximately 1.5–1.7A.
Thanks Leo. I’ll watch the temperature of the Y stepper driver. It has a heatsink, but I should make sure it’s properly attached. I’ll verify the current as well.
I had already reduced my speed to 350mm/s max and 500mm/s2 acceleration - (way down from the defaults of 500/5000) - so I think thermal and current are worth investigating. 300/500 should be within the design limits of the machine.
Can you provide specs for the stepper drivers? I’m going to order some from Amazon as spares and to replace my Y driver to see if things improve.
Standard 3D printer driver modules supporting the STEP DIR EN signals and 1/32 microstepping are compatible (DRV8825/TMC2209/TMC2226/others).
Has the operation become stable after reducing the speed?
Hi Leo, Yes - the motion is more stable running at 50%. I checked the driver current and was quite low - so I readjusted vREF to ~2.4V on my Y driver. I put the speed/accel back to default 500/5000 and set the speed to 100%. I could move the machine manually from end to end with 100% reliability, but when the machine does the same moves during a job, the Y motor then stalls on the first movement.
I then set the speed/accel to 500/1500 - same stalling problem.
Last I tried 50% speed with 500/1500 the machine seems OK for 1 or 2 placements, but I haven’t run a full job with it.
I’m going to order some TMC2209 drivers today. My TMC2226 drivers as originally received in a V2 MC board have a missing pin - do I need to cut the same pin on a TMC2209 for the V3 PPMC board? My driver was moved to a replacement V3 board a while ago (Homing problems).
I readjusted vREF to ~2.4V on my Y driver
The default TMC2226 Vref (Vref=Irms/0.71) for the Y-axis is approximately 2.1V, corresponding to roughly 1.5A Irms current. A 2.4V voltage will result in higher current draw, but overheating remains a concern.
Do you still have the 24V 4010 fan included in the original kit? You could test mounting the 4010 fan on top or the side of the Y driver, then directly connecting it to the 24V or VIN connector to provide air cooling for the Y driver. See if this resolves the previous step loss issues.
It appears your V2 version is an earlier model. The previous driver also used TMC2226 with mainboard VCC=3.3V.
It is recommended to switching to the new MC_V3.X mainboard (while also replacing the HCB_V2.0 headboard). The driver’s VCC is now 5.0V. You do not need to modify the driver hardware, simply use it as is.
Thanks Leo.
I’m already running a V3 main board and V2 Head board. My TMC2226 drivers were from my original V2 main board (a very early model) that was replaced due to the homing issue.
At 2.4V VREF, the Y driver eventually shuts down due to overheating. After about 10 placements from a feeder at the front of the machine ( lots of Y travel) it gets REALLY hot and stops stepping at all - no grinding, just no Y movement. I went back to 2.1V or so and it’s better, but still hot.
I’ll try the fan, and I also have 5 new TMC2209 drivers to help diagnose.
For now I’ve also reduced speed/accel to 300/300 in order to get my job finished. This works OK and is still faster than placing by hand.
It does appear that the issue is likely caused by the driver overheating.
The heat generated by the TMC2209 may not differ significantly from that of the previous TMC2226.
I recommend trying to use an additional 24V fan for cooling. Design and 3D print a fan mounting bracket to install the fan near the Y-axis driver for active cooling.
Hi Leo, i added the fan to the TMC2226 driver, and it didn’t make a difference. I then replaced the driver with a stock BTT TMC2209 driver set to 1.5A. Interestingly, this one was worse than the TMC2226. With the new driver it would fail on even manually jogging the Y axis 100mm.
With some troubleshooting it was obvious that one or both of my Y axis linear rail carriages was binding under load. I removed both Y rails and replaced them with new rails and carriages, and I’m now able to run at 500/2500 with the TMC2209 . This is a huge improvement.
There’s nothing obviously wrong with the original linear rails, but clearly something was not right. I’ll clean and rebuild them as spares.
Thanks for all of your help. With a fan and new drivers I’m sure the machine will work even better from now on.
Thanks for the feedback. It turns out mechanical resistance was the cause. I’m not sure if foreign particles are causing the stuttering.
Regarding linear rail lubrication, you can use lithium-based grease (without solid lubricants) as recommended in some official rail maintenance instructions. Grease can sometimes also keep small particles out.
Thanks Leo. There’s no grease port on the original carriages - but the new ones have a hole for it. I’ll be sure to keep them lubricated.