Modded marlin to use E1 as second Z driver???

Hi folks,
Does anyone know if any experiments have been using extruder E1 as a second driver for the Z axis?
I wondering as, I'll admit it, messed when I bought my steppers and stupidly got 2.4A per coil models.

Even running my Drv8825 at 1.8A I suspect the z steppers just aren't getting enough juice. Very flaky, going out of sync, freezing. I've tested at full step to 1/8 with max z velocity of 4mm/s or less and problems continue. Oh, I've made sure steps/sec stays under max 15000 s/s

If I could off load one z stepper onto E1 might be a better solution then buying new steppers. Which I'm going to do anyway. Just not right now.


All suggestions appreciated,
Andrew

Edited 1 time(s). Last edit at 09/28/2015 02:14AM by friarfish.

Hi,

Have you slowed down your acceleration rate?
While max z velocity is one thing its more about the rate you accelerate to get to a max figure.
Hopefully you have adjusted the stepper driver pot to see if increasing current still causes your stepper motors to loose steps, generally stepper drivers will start to overheat and shut down being run at max amps.
Also make sure that there are no jamming and everything is aligned with your z axis.



I am using a ramps1.3 board and use the E1 (2nd extruder) stepper driver for my second Z stepper motor. Works very well.

Only issue was with auto homing the two Z stepper motors, I have posted on this form page a couple of days ago ( 25th September ).
Marlin, Delay when homing dual Z stepper motors (Auto sync feature), using Z_DUAL_ENDSTOPS .

You can see a picture of my Openbeam CoreXY machine there.



Cheers Bruce, New Zealand

Hi Bruce,
just slowed the Z back down to 2mm/s at 1/8step but haven't checked it out yet.

I've pretty much maxed out the drv8825. I,as I have said elsewhere, stupidly brought
2.4A/coil steppers. I think you can see what two of those can do to a drv8825.

At least, as you have shown, it can be done with a ramps 1.3. Suggests maybe I
can do it with a ramps 1.4.


Many thanks,
Andrew

What you want, ie one stepper driver per Z thread, using e1, has already been done

see [github.com]

Edited 1 time(s). Last edit at 09/29/2015 01:08AM by Dust.

Hi Dust,
figured that one out.
All the guides online said keep away from the config_adv.h, which I did.
If I had ignored that advice, I would have found the solution.

Many thanks,
Andrew