1 Topic by accusedmonk

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Topic: 14:1 Geared Bowden Extruder

This tank came in today, so I'm going to draw up an extruder for it and slap it on my doodle.  The gearing is 13.71:1 giving it 425oz-in of permissible torque.  I have the E steps at 32nd's atm, which would give me 2480 steps per mm.  I really doubt I'm going to keep it there, I just want to see what she'll do.  I'll probably tune it back down to 16th's that way it will be basically 14 times my stock resolution.  I shouldn't need more than that to eliminate moire.

Here's a comparison next to the X axis motor:

http://i.imgur.com/Xenq1q6.jpg

Bowden SD3, Rumba, E3D hotend, Mk5 with RtRyder changes, Direct drive Y axis and bearings, GT2 pulleys and braided fishing line, Lawsy linear bearing conversion, M3 Z screw.

2 Reply by accusedmonk

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Re: 14:1 Geared Bowden Extruder

A rough version 1.0 is drawn up and printing atm.  Should be able to finish installing it tomorrow.
http://i.imgur.com/VODBKDD.png?1

Bowden SD3, Rumba, E3D hotend, Mk5 with RtRyder changes, Direct drive Y axis and bearings, GT2 pulleys and braided fishing line, Lawsy linear bearing conversion, M3 Z screw.

3 Reply by accusedmonk

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Re: 14:1 Geared Bowden Extruder

Got it all on and running this morning, only issue so far is the ptfe tubing doesn't want to stay in the extruder ha.  There's quite a bit more friction in these tubes than i thought.  I'm probably going to super glue it.  I have push fittings from e3d but they let the tube flick up and down a mm or two, which eliminated my retraction on the previous setup.

It's very slow to retract with 2480 steps/mm, I'll have to fiddle with things until it's a useful speed.  I do have it limited in firmware to 7mm/s though.

The design came out great though, works as planned.  Can't complain for only about 2 hours of total work. I wasted more time last night trying to find songs to listen to.

I have sticky back rubber between the mount and the frame, keeps things quiet.  The only other issue i need to fix is the clearance for the filament.  Might make a floor or bottom of the frame spool holder.


Related pictures:

http://i.imgur.com/VAVWC63.jpg

http://i.imgur.com/hvviYiP.jpg

Bowden SD3, Rumba, E3D hotend, Mk5 with RtRyder changes, Direct drive Y axis and bearings, GT2 pulleys and braided fishing line, Lawsy linear bearing conversion, M3 Z screw.

4 Reply by elmoret

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Re: 14:1 Geared Bowden Extruder

You can notch a credit card and slide it in to take up the gap on the E3Dv6's embedded bowden connector.

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5 Reply by wardjr

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Re: 14:1 Geared Bowden Extruder

elmoret wrote:

You can notch a credit card and slide it in to take up the gap on the E3Dv6's embedded bowden connector.

Just running into the same issue CC is a good idea just don't use the one you use at the Filastruder store tongue

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6 Reply by timp610

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Re: 14:1 Geared Bowden Extruder

Any reason you went with such higher gearing?  Ony my large scale delta I only use 5:1 and its plenty enough to shred filament and also suffers slow retracts.  On a SD the bowden tube is short enough you can probalby get away with just a plain NEMA 17

7 Reply by accusedmonk

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Re: 14:1 Geared Bowden Extruder

elmoret wrote:

You can notch a credit card and slide it in to take up the gap on the E3Dv6's embedded bowden connector.

That's not a bad idea, if i can't get a secure fit with it, I'll make a bigger hole and reinstall the push fit with a spacer.


As for the gearing, i wanted very smooth operation from the stepper.  The slow retractions i can take care of by switching to 8 micro stepping instead of 32, or lower if i have to.  I have read in places that 5 to 1 still wasn't quite enough to eliminate moire.    I didn't have torque problems with the stock motor in the bowden setup, but it was still pulsing even with 32 microsteps.

Bowden SD3, Rumba, E3D hotend, Mk5 with RtRyder changes, Direct drive Y axis and bearings, GT2 pulleys and braided fishing line, Lawsy linear bearing conversion, M3 Z screw.