multiple filament bowden extruder drive
Description
i am currently preparing to test this, but wanted to get it out there. current issues are that is does not have good access to the drive mechanism for cleaning or feeding filament and that much of it was designed to be machined instead of printed. the side plates are to big for a cupcake, but i ws able to print a few of the pieces on one. it may also not be compatible with other motors until there is a redesign, as the motors are integral to its strength.
if anyone has improvements, let me know.
EDIT: added an IGES assembly file(let me know when you find its broken, and how to fix it) and SW2005 part and assembly files. also added an exploded image
EDIT: lookes like this has been worked on a bit already by wildseyed thingiverse.com/thing:10783 . not sure if i should list it as derivative.
Finally got more than 1 hot end functional at a time, so to check out the filament drive in action see youtu.be/CVaYHlLkvWM
and youtu.be/yqAGEqaoPg4
it works! all 3 filaments running:
youtu.be/po8KyagUsY4
youtu.be/-X-azhcsqdM
Instructions
i am using:
2 - 32 pitch gears of 19 and 54 teeth.
4 - 5x13x3mm bearings for the drive and cam shafts.
3 - 608 bearings for idlers.
4mm teflon tubing.
3 - 4mm x 1/8 pipe push-lock fittings.
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Hi fritzgutten, Great concept and design. I've got a dual extruder setup, but it's not nearly this elegant. Any updates on the design or how it's been performing to date?
finally got all 3 running! see the horrible results here:
still much tuning left to do, but i'm calling it functional. 8-)
Finally got more than 1 hot end functional at a time, so to check out the filament drive in action, see: youtu.be/CVaYHlLkvWM
only 2 colors at the moment, need to finish another hotend.
Could you share your original design file(s) too? Stl-meshes are much harder to handle in most cad programs than the native format (or imported format).
I really like the design, but I think the separate stepper to stand in for a multi way swicht is not a good idea. If you start your firmware up, you have no way to know what state the machine is in.
Replace the switch stepper with a few cheap 3$ servos (or 5$ ones if the cheapies are too weak) an
d drive the servos with PWM from the arduino and a separate 5V line.
thanks for the input.
i'd be glad to share my files, what would be most universal? I'm running solidworks 2005.
as for the stepper drive on the filament selector, i will be installing a home switch on that axis. I'm unsure how current electronics will handle the stepper or home switch, but figure its an option as dual extruders are coming out.
many printers are running or have run by manually setting the home position, this could be an option for the filament selector motor as well.
hobby servos may indeed be an option, but control is less understood for myself. driving multiple servos would simplify the mechanical setup, but complicate the programming and control scheme.
I am using EMC2 and the use of a stepper is not much of a concern for my use.
Is the idea to have N hot ends for N filaments, or to have the filaments join into one hot end?
So... it looks like you are using one drive to "select" the feed and apply pressure on the selected filiment and the other is the actual drive, which drives all three, but only if they have pressure on them. Correct?
wow! i was dreaming about something like that! Can you post some more info about it's inner working? i'm no engineer... :)
I'll see if i can get around to it. busy constructing my other hot ends to test it out.
but basics are : the drive shaft uses hobbed grooves like most, except it is about 2 inches long or so and has 3 grooves equally spaced. the idler arms press the filament into the grooves independant of one another. the arms are vey similar to others out there. instead of using springs or a lever to engage the filiament, there is a 3 lobe cam running along the back of them that can be rotated to select which idler is engaged. filament is selected by isuing a gcode command to the cam motor to rotate to the proper orientation to engage the correct cam.
License
Hi, great work on the extruder! I was wondering if you cold explain, in a little more detail, how your print file controls the motor to select the new filament. Are you hand coding the motor rotation to select the filament or are you using a "T" (tool change) gcode to select the filament?