I have been experimenting lately using a bowden extruder to push filament into a BMG which then extrudes the filament (see pics). It worked the first time without fuss. I have worked with the prusa MMU and various "switching" nozzles with little success. Other than the MMU, TPU was not viable and I had lots of jams and lack of tolerance. The MMU was a little over-engineered for me which in concept works well, but the inaccuracies of real-life made it unreliable.

Anyways, to start, I am running a Duet 2 wifi with a Duex 5 add-on board. My loading extruders are 1:1 geared 3D printed bondtech bowden extruders and my printing extruder is the 3:1 geared bondtech BMG extruder direct drive. My hotend is an e3d v6 with copper heatblock, 50W heater, and nozzle X nozzle. The build volume is 300 x 300 x 400 mm^3. Right now I am running two feeding hotends, but in the future I will run up to 6 because I can.

How it works. The feeder extruders each have a filament loaded partially into the first length of bowden. Each tool has two drivers running simutaneously in mixing mode with a 1:1 mix ratio. When tool 0 is selected, E drivers 0 and 1 are running. When tool 1 is selected, E drivers 0 and 2 are running... etc. When a tool is selected, both motors push the filament through the bowden splitter and into the BMG, out the nozzle. The benefits of this is that I maintain the direct drive setup and no longer have to maintain tight tolerances in the bowden tubes or the splitter wich is where most clogs come from.

In the future, I plan to add limit switches for clog detection and peace of mind.

Let me know what you guys think.
Thanks

@dc42 Thanks for your time! I have checked to make sure that the commands are the same and I will reach out to filastruder.

@oliof Theoretically the extruder motor moves 1/3 of a step faster, but because it is geared, I do not think it is a problem. Other than that, the extruder calibration is the same.

@oliof Theoretically the extruder motor moves 1/3 of a step faster, but because it is geared, I do not think it is a problem. Other than that, the extruder calibration is the same.

I have been experimenting lately using a bowden extruder to push filament into a BMG which then extrudes the filament (see pics). It worked the first time without fuss. I have worked with the prusa MMU and various "switching" nozzles with little success. Other than the MMU, TPU was not viable and I had lots of jams and lack of tolerance. The MMU was a little over-engineered for me which in concept works well, but the inaccuracies of real-life made it unreliable.

Anyways, to start, I am running a Duet 2 wifi with a Duex 5 add-on board. My loading extruders are 1:1 geared 3D printed bondtech bowden extruders and my printing extruder is the 3:1 geared bondtech BMG extruder direct drive. My hotend is an e3d v6 with copper heatblock, 50W heater, and nozzle X nozzle. The build volume is 300 x 300 x 400 mm^3. Right now I am running two feeding hotends, but in the future I will run up to 6 because I can.

How it works. The feeder extruders each have a filament loaded partially into the first length of bowden. Each tool has two drivers running simutaneously in mixing mode with a 1:1 mix ratio. When tool 0 is selected, E drivers 0 and 1 are running. When tool 1 is selected, E drivers 0 and 2 are running... etc. When a tool is selected, both motors push the filament through the bowden splitter and into the BMG, out the nozzle. The benefits of this is that I maintain the direct drive setup and no longer have to maintain tight tolerances in the bowden tubes or the splitter wich is where most clogs come from.

In the future, I plan to add limit switches for clog detection and peace of mind.

Let me know what you guys think.
Thanks

I figured it out, there was a rouge piece of Gcode in my homing file that enabled stall detection at crazy high sensitivity so every time it moved, it paused, stalled on the pause, and resumed. Thanks almost everything works now!

Config file here -> 0_1566767557836_config.g

Video of the problem google photos

Gcode file I am trying to print 0_1566767726972_3d benchy 2 color.gcode

Anybody have any ideas. It is a custom prusa i3 with a 3 in 1 out nozzle and the IR sensor. I updated the config.g when i switched extruders and it worked perfectly for a while. Things started to get wierd and I flashed new firmware and now this happens. Reverting does nothing.

Good point, the tpre should allow extruder movements. Is there a way I can change the firmware myself or do I have to wait for the next release. Thanks

@dc42 Instead, to prevent changing other peoples' file setup maybe add a tcurrent file. One that would run after the tool is selected.

It wont let me extrude in tpre files as no extruder is selected

Is there any way for me to control stepper motors without their drive letter, controlling them via drive number. I want to write custom tool change macros, but they can't do what I want them to do with the limited pre, post, and free macros. I always get the no extruder selected because of files being called between tool changes. I want to call a tool that is not selected to load the filament into the extruder, but I can't find a way to do this.
Thanks

Hi, I built my own MMU2 and configured the Selector and bearing rotation mechanism with endstopless homing, but I cannot figure out how to configure the extruder drive motor with the five drive gears. How do I do that on the duet. What commands do I have to add to my config.g. Thanks

ok, thanks. Any way to reach out to @dc42 or someone else that can help?