Automation Technology Extruder Motor Current?

[exalt]

Does anyone know the right motor current for Automation Technology stepper motors, at least for the E value?

Rostock Max v2. Been having on-and-off airprinting issues due to PLA filament melting in the cold end(EZstruder), lumping and jamming up the EZstruder, heat and pressure squishing the filament too thin for the hobbed gear to grip on, kinking/curling the filament and the incoming filament becoming instant ramen in the ezstruder, etc etc.

It's quite obvious that the cold end is getting way too hot on longer prints(>2hour), actually burns when you touch the stepper motor. It even managed to glass transition and warp the EZstruder cover I printed in PLA.

In the assembly guide v3 it says set to

If your kit was shipped with the Kysan or Automation Technology stepper motors (we covered
that earlier, remember?), you're going to need to make a small tweak to the firmware in order to adjust
the current drive that they need.
Click on the tab in the Arduino IDE marked “Configuration.h”. At line #701, you should see
this text: #define MOTOR_CURRENT {175,175,175,200,0}.
Change that line to this: #define MOTOR_CURRENT {155,155,155,165,0}

Which I did, but the E value is clearly still far, far too hot.

Contrastingly, the commented portion in repetitier.ino:

// Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A) use 140 for xyz and 160 for the E if using Kysan motors and 175 xyz and 200 if using wantai motors

Then there's this:

Ok, I changed the current setting according to SeeMeCNC down to 140,140,140,140,0. Did the same print in the same color and it printed, motor is still getting warm but not near as bad as it was before. Now I just need to figure out this stringing issue and I should have this thing tuned pretty good.

The 155 value for the XYZ haven't given me any problems, so should E be 140, 160, or 165? This issue has been an endless source of frustration with its unpredicatability and evasiveness. The printer lives in a room which reaches 35degrees C during the daytime, incidentally.

[Xenocrates]

I would start at 160, work downwards until it no longer causes issues. I would also potentially add on a heatsink to your extruder, such as the following:
http://www.moddiy.com/products/3M%252d8 ... mm%29.html

http://www.moddiy.com/products/Aavid-Th ... mm%29.html

http://www.moddiy.com/products/3M%252d8 ... mm%29.html

http://www.moddiy.com/products/3M-8810- ... tsink.html

The more volume/fins it has, the more heat it will conduct away. However, it will eat space, as well as potentially act as a magnet for wiring from the main harness.

[DGBK]

I'm in the same boat, and it is really frustrating to think that the manual tells us to use a higher current than we should. It would be great if we could pinpoint better settings. My motor gets extremely hot to the touch. I put a very large heat sink onto the motor, but it only marginally helped with the heat issue. We shouldn't have to rely on fixes that aren't part of the kit to get our extruders down to a workable operating temperature. I'm constantly getting filament jams on longer prints that I believe are related to this issue.

I just bought a new all metal extruder that will be used in a flying configuration. I'm hoping the shorter bowden tube, a better constrained filament path, and the metal's natural ability to dissipate heat will finally get rid of my jamming issues.

[Xenocrates]

Funnily enough, mine ran at the specified current settings, and I only started getting overheating issues after I put a 150W heater bulb next to it. I suspect there is a good chunk of variation in the stepper motors, which leads to issues. I believe that if you tune downwards until you start missing steps, and then come back up say 5, you should be able to minimize temperatures.

[exalt]

DGBK, you might want to download and flash the new firmware. I checked and it seems in the latest revision in github the currents are 140 for XYZ and 130 for E by default, with a different amount specified for wantai motors. It's a shame that I had to find out by complete coincidence, I only found out things had changed when I wanted to download repetier onto a new PC to edit the motor current. Sure, I have no problem with the motor overheating now, but it would be nice to for someone to send an email or something to let us know the firmware has been updated..

[DGBK]

I'll try those settings to see if it helps.

Thanks

[RichardMI]

A work around is to clamp a small desk fan near the EZStruder to blow on the motor. It barely gets warm.

[DGBK]

The new settings seemed to have helped quite a bit. The motor is still warm to the touch, but it is not longer hot enough to cook food. Thanks for the catch on the currents.

[Chaoite]

Question about how to apply changes to the motor current, I made changes to the eeprom through matter control that arent found in my configuration.h file on my computer. Is there a way to make changes to the eeprom on the printer without reflashing the board and having to re-do my horizontal radius calibration and such?

[Xenocrates]

Yes, you use Mattercontrol or Repeteir host to change them. You would need to change the EEPROM mode for a reflash to adjust those numbers anyways.

[knabo]

I am glad I can find answers on the forum. SeeMeCnC should have a newsletter.

This problem just showed up for me after a few months of printing. The thing that made the difference was putting the plastic covers on the lower half of the Rostock Max V2. After about 8 hours of printing some horizontal shifting showed up. My currents are set to what the old user guide said (150 etc)

I am printing a 12 inch tall flute. Up to about 6 inches it was fine. Then the shifting started. After reading this thread I removed the covers and the print smoothed out again.

Looks like I will be changing my motor currents this weekend.