Dual extruder config

Hi guys!

I have a couple of Prusa i3 working perfectly. Then, I decided to upgrade one of them with a dual extruder set. I have tried to mount two hotend aparts each other x-axis of 24mm.

• Firstly, I tried to use 2 x Universal 1,75mm – 0.40mm nozzle E3Dv6, both of them of course with cooling fans.
Results: filament slip everytime after a few minutes.

Tried from 185ºC to 230ºC but temperatura is not the issue as filament flow fine if I push it by hand.
This was using bwoden extruders with a MK drive.

• I though it would be because this drive system and I installed two Wade extruder but bwoden system.
Results: filament slip everytime after a few minutes.

• Then I decided to change using 2 x j-Head hotends 1,75mm 0.35mm nozzle.
Results: filament slip after a few minutes even trying to print at 225ºC.

Finally, I though it can be a firmware feedrate issue or something else I can’t find..

I attached on slic3r screenshot of my Hephestos printer printing at 32mm/s with an awsome quality!!
And also I attach a Simplify3D screenshot of dual system trying to print speeds that is always slipping filament at that veeeery low speed: 8mm/s

I also attach a firmware feedrate config..
I really appreciate any kind of help with this frustrating issue.

Many thanks to all!

Are you using Arduino/RAMPS? If so then I suspect that your extruder stepper motor drivers are overheating.

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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].

Yes, I just forgot to mention, I'm using Arduino+Ramps 1.4. You mention overheated due to overload working preasure or due to distance with hotend? This last one not possible due bowden system is 60cm separate hotend-stepmotor.

About overheated due too much work, does the motor would be hot? Mines are absoloutly cold..

The stepper driver. When your drivers are not calibrated correctly for the load, or the load is more than what your driver can push out, the driver will overheat. An overheated driver will not step a motor correctly or give proper torque. Are you using drv8825 or A4988 drivers. The latter may be too weak for your motors power requirement.

Your voltage may also be too low. This would result in not enough power being sent to motors.

Edited 1 time(s). Last edit at 02/12/2016 01:21PM by gmckee.

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Prusa i3 Rework - Ramps 1.4 - E3d Lite6 - Full Graphic LCD Controller

Hi, torque seems to be quite good. If I hold the filament it really grip it fine and even holding strong the step motor keep extruding. I tried to do this job without hotend, just the extruder to check torque. It's like it can't push the filament inside the hotend after a few minutes.

A few things that prevent the feeding of filament:
1 - insufficient idler pressure in the extruder
2 - insufficient stepper current, the stepper motor skips/looses steps. You can see the motor stop turning.
3 - this is rare: actual hotend temperature is less than the what the hardware thinks it is.

If the stepper motor is cold, then it's most likely #2. Stepper motors on all my printers warm up a bit while running.