Im building a delta atm then I will be able to test higher speeds. Above 60 my machine (eventobot) starts to fall apart 
So I stopped going over this, its possible that the what I see as under extrusion are just artefacts from a shaky frame
and in order to use 60mms with the vulcano I though I try two motors
]]>60 mm/s printing speeds? I think you need to check your tension or VREF--with the crappy stock extruder motor+MK5 on my SD4 I can push 150mm/s printing speeds with no feeding issues assuming high enough temperature.
Edit: 1mm layers push a LOT of volume. 60mm/s is probably too fast for that layer height! You're asking for almost 3X the material at the same speed!
Yep the problem isn't one of force rather flow. You could try a serious increase in temperature of course that comes with it's own set of issues.
]]>Edit: 1mm layers push a LOT of volume. 60mm/s is probably too fast for that layer height! You're asking for almost 3X the material at the same speed! No matter how much torque you throw at it, you won't be able to push those volumes at those speeds. Even the volcano simply isn't capable. Tim (elmoret) has commented on this before as well and broke down the math:
]]>and what extruder are you using? I have a 39:11 geared airtripper 40cm bowden with e3d V6 and I start getting under extrusion above 60mms.
The idea with the two motors came to me when I installed the Vulcano upgrade from e3d. 1.2mm nozzle 1mm layerheight 2mm layerwidth and me max speed is 15mms so there is more capacity if only the push force from the extruder is keeping up.
]]>http://forums.reprap.org/read.php?160,313848
http://forums.reprap.org/read.php?219,242163
You can do further searches on running 2 z motors from one driver. In this case you would reverse the wiring on the second motor to get the spin in the opposite direction.
Why do you want to use 2 motors to drive the filament? My extruder is totally capable of crushing and folding the filament when there is a jam. The stiffness of the filament puts a limit on the amount of force you can apply to it, which can already be exceeded by a quality gear and spring-loaded bearing.
]]>I heard of "ditto mode" in repetier is there something similar in marling? or what would be your idea?
]]>Im building an extruder with two motors but only for one nozzle. The 5th driver slot on the RAMPS is also ideal to drive the second motor.
What I cant find is a way to enable 2 motors on one extruder. All I can find on google is dual extrusion. I also can activate the pins for the 2nd motor but can someone give me a hint how I can start programming the 2nd motor to do what the first does only in reverse.
Cheers
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