Einsy Rambo Dual Z Motor Issues

Hello All,

Apologies for my first post to be asking for help, however, I am completely stuck.

I am building a Prusa MK3 clone and so far have all the components assembled and good to go, the only issue I am having is the dual Z motors running from the Einsy Rambo.

Whenever i run the motors i am experiencing incredibly low torque, to a point where i can barely move the Z axis, if i unplug one motor I have no problems with either Marlin or Prusa firmware and i can spin the axis fine.

So far i have tried the following ( am not next to my printer to post my Configuration.d and *adv.h - I will do that later)

New Einsy Rambo (Genuine)
New stepper wires
Prusa mk3 Firmware
Marlin 1.19 Firmware
Adjusted Acceleration
Adjusted Feedrate
Motor Current
Chop Modes
Adjusted Jerk
New POM nuts
There is no binding I can move lead screws by hand easily

I am using a 24v power supply as i am aware 12v is no good here, when i use Marlin 1.1.9 I can use both motors but only just. The Prusa firmware is almost useless and cannot drive my Z axis. The two things i have not tried are changing my motors and the Z axis lead screws.

Currently my motors are rated to 1.6a and I am using a TR8x2 lead screw, my thought is now that the motors current rating is too high and perhaps a TR8x8 lead screw would be better.

I am at a loss how little torque the Trinamic 2130 can produce its paltry at best , any advice here would be great, Its got to be motor related but before i throw anymore money away I thought I would ask people who know a lot more than me about this.

Thank you in advance

I've never used the Einsy, but you should be aware that Prusa has chosen the motors he uses very carefully to work well with the TMC2130 drivers. A rated current of 1.6A for the motors higher than optimum for TMC2130s, they work better with a motor rated current of about 1A to 1.2A.

The two Z motor outputs on the Einsy are connected in parallel. I am surprised that they did this, because series connection makes much more sense for TMC2130 drivers. You may get reasonable results if you connect the two Z stepper motors in series and connect the series combination to just one of the two Z motor outputs.

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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].

Thank you for the response, I had thought that 1.6a is too much so i tried 0.4a motors tonight and i cant even get those to move, they just resonate, This throws me completely I thought a 0.4a motor would be much easier to spin.

It had crossed my mind to wire in series but i expected the Einsy to be done like that, parallel seems crazy running two motors when the rated current are so low

I would expect 0.4A motors to work if you are using 24V power. Are you sure that the motor wires are phased correctly? Are you sure that you are not trying to move the Z axis too fast, or you have the Z acceleration set too high?

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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].

I think i am almost there with Marlin 1.1.9

I have wired the Z steppers in Series and I noticed that the R_SENSE was set to 0.11 when it should have been 0.22, along with this I have added heatsinks and cooling fans on both sides of the Einsy Board, the Z axis seems a lot happier but still has problems running any acceleration above 100.

The Prusa firmware is still a no go, just wont provide enough torque whatever i try, I have ordered some Prusa MK3 Z axis motors, hopefully that resolves the Prusa firmware issue.

I still don't get why the 0.4a motors didn't work, I tested them on my MKS GEN 1.4 using the same cables and they turn no problems, as soon as they go near the Einsy they wont work properly, something is still nagging at me I may have two bad boards, one is a Chinese clone so quite likely its not made as well but the Gen one should be good.

Anyway 1.1.9 is working for now, seems the serial wiring and R-SENSE sorted it for now, thank you all for the suggestions and help very much appreciated.