Extruder Motor Overheating

I have three Cetus MkII's with dead control boards converted to RAMPS, 12V 30A PSU, E3DV6, and other stuff. Their extruder A4988 stepper drivers are set to 1/3 current by their potentiometers before they skip and I have a 12V 0.1A 30mm fan cooling each extruder. I print at 40mm/s to not overwork the motor. Originally overheated in 0.5 hrs now it overheats in 1.5hrs. Progress I guess.

Any ideas how to not make the filament in them melt and jam? The extruder gears are pressed flush with the motor so there is no buffer space between the motor and filament.

I can mount a second 30mm fan on each which would look really weird or try adding their 40mm 5V 0.34A or a 0.14A fan I have on hand to cool the motors but I already have a servo pin working a 5V 0.14A 40mm fan cooling each RAMPS. I am not sure how much more the 5V regulator can handle. Not sure if a 3D printed fan shroud would help or trap heat. Right now the 30mm fan is cooling the back and top of the motor to maximize surface area.

I have some TMC2130 stepper drivers, over kill for the extruder motor but maybe just enough to get more torque through higher micro stepping? These high inductance motors are really weird, I don't know what to think and I don't want to waste the TMC drivers.

I might order some 40x40x11 heatsinks and 40x20x11 heatsinks but that could take months to get to me.

I'd prefer not spending more money or waiting months for 40mm heat sinks. Any ideas are appreicated, thanks!

Edited 2 time(s). Last edit at 04/05/2020 03:56AM by Power3DPrinting.

Is there a part number on the motor?

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Sorry all of them have labels that have been rubbed blank. One of them says "_____201" or "_____204"

The most I know of them is that they are 32.3mm long and are 200 step motors and the two sets of coils each offer ~25.5-26 ohms of resistance. With 12V they will draw about 0.46A per loop so 0.92A or 1A motors by that logic?

Edited 2 time(s). Last edit at 04/05/2020 12:58PM by Power3DPrinting.

With resistance that high, those are lousy motors to use in a 3D printer. Look for new motors with very low resistance- like <3 Ohms, and a voltage rating around 3V or less.

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Hi, what do you mean look for new 3V motors?

I checked some motors on other printers and you are right they all read under 3ohms. Unfortunately all the stepper motors on the Cetus read with 25-30 ohms. I don't really have any replacement motors for the extruder without ordering new hob gears and redesignng the extruder from scratch.

Edited 2 time(s). Last edit at 04/05/2020 04:04PM by Power3DPrinting.

Those motors need more than 12V to get good performance out of them. Either upgrade your machine to 24V power (which isn't straightforward with RAMPS) or replace the motors.

The axis motors may have the same issue.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Dang, I only just replaced all the electronics, so only way out is to replace all the electronics again or order new parts for an extruder?

Axis motors work fine, they certainly get hot but none of them are handling filament and they are not skipping steps or melting their metal mounts, just obnoxiously loud.

Edited 3 time(s). Last edit at 04/05/2020 04:09PM by Power3DPrinting.

Also hi DC42, still selling those IR sensors? Really cool to still see you on the forums.

Quote
Power3DPrinting
Also hi DC42, still selling those IR sensors? Really cool to still see you on the forums.

Thanks! I recently handed over production of IR sensors and PanelDue to Duet3D Limited. I don't have time to do production management and testing any more because of all the work I do on RepRapFirmware and new hardware development these days.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Cool to hear about passing production to duet, good company, I ordered a panel due for another printer, I did not realize you designed that too.

Welp, I spoke too soon about the motors, I did several dozen test prints and found the motors create a significant amount of salmon skin effect on the perimeter walls and the Cetus MkII fixed extruder gear system needs to be overhauled because it cannot handle retractions of any degree without chewing a chunk out of the filament and stop extruding. I will probably have to order at least 9 40mm long Nema 17's to replace the XYE motors and 6x20 tooth pully's and 3 hob gears. Probably overhaul the whole Extruder carriage while I am at it. Rip me. Tiertime really made weird choices in the design of the Cetus printers. I really wish they could have used normal parts. I don't know what they were thinking making everything so proprietary and unique.

Edited 2 time(s). Last edit at 04/06/2020 06:59PM by Power3DPrinting.