Dual Extrusion at AOHQ

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kcchen_00
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Re: Dual Extrusion at AOHQ

Post by kcchen_00 » Fri Feb 20, 2015 2:33 pm

This may be a bit premature...

Any chance work has started on a dual extrusion solution for the metal hotends? :)

jebba
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Re: Dual Extrusion at AOHQ

Post by jebba » Sat Feb 21, 2015 1:08 pm

kcchen_00 wrote:Any chance work has started on a dual extrusion solution for the metal hotends? :)
Not yet, but definitely on the todo list. Files will start appearing here, as we have them:

http://devel.lulzbot.com/TAZ/accessories/

Thanks,

-Jeff

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piercet
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Re: Dual Extrusion at AOHQ

Post by piercet » Mon Feb 23, 2015 6:09 pm

I still think we need some sort of gatling cannon derived rotary rapid fire multi extruder!

inventabuild
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Re: Dual Extrusion at AOHQ

Post by inventabuild » Sun Apr 12, 2015 1:12 pm

With the Lulzbot current dual extruder design I find that if I adjust the height of the 2nd extruder using the thumb screw then the height of the 1st extruder also changes. In my opinion this makes for too many iterations to level both extruders. Therefore, I'd like to see the dual extruder improved so that adjusting the height of one extruder does not affect the height of the other.

Also, the 2nd extruder is affected differently than the 1st extruder by any slight discrepancy between the alignment of the x-axis smooth rods because the 2nd extruder sticks out a greater distance from the x-axis than the 1st extruder. If both extruders ride the x-axis the same way it will help mitigate any relative alignment issues between the two extruders that is due to slight x-axis misalignment.
Last edited by inventabuild on Sat Apr 18, 2015 8:15 am, edited 1 time in total.

mushoo
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Re: Dual Extrusion at AOHQ

Post by mushoo » Mon Apr 13, 2015 1:04 am

I'll pop in here to both echo inventabuild's sentiments (the main reason I moved away from the Lulz dual extruder mount is that leveling the extruders was such a major headache), as well as (yet again) explain my current solution to those issues.

Basically, I bought an E3D Chimera. I designed a custom mount for it, using a Dglass 3D "HPX2-Max" dual extruder - this extruder uses a single stepper motor, and a servo, to act like two extruders. The spacing between the nozzles in the Chimera and the output of the HPX2 extruder were a bit different, so it is *technically* a bowden system - but my PTFE tubes are only about 3/4ths of an inch long. Setup was a huge pain, but it's working pretty smoothly now. For a short while I'd run it as a true bowden system - it probably would work OK using the Lulz dual mount for some Wade's extruders, and then piping the output of those to the Chimera.

Anyway, nice thing about the Chimera, the heat blocks slide - not screw - into the heatsink. Levelling them is as easy as mounting it all up, and then tightening some screws. To be honest, I didn't even have to do that - putting the heatbreaks in as far as they would go kept them leveled within .05mm.

The other nice thing - the two nozzles are always EXACTLY 18mm apart in the X axis, and 0 in the Y axis. No need to calibrate, print test objects, tweak settings and offsets constantly, etc.

The downside: Flexible filament is a pain. I'd had Soft PLA working via the true bowden setup (surprisingly), and I've gotten it working with the HPX2-Max with a small length of 3mmODx2mmID PTFE tubing strategically placed inside the extruder body (and idea I got from the flexistruder). Over the past few days I've printed about20 hours worth of Soft PLA with no real issues.

The other downside: 1.75mm filament ONLY. The Chimera is not designed for anything else.

Overall though, very, very happy with it. The only improvement I can think of (beyond true support for flexible filament) is a servo-based nozzle retraction. If a nozzle isn't in use, a servo retracts it up 2-3mm, so that there's not any ooze left on the print.

inventabuild
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Re: Dual Extrusion at AOHQ

Post by inventabuild » Mon Apr 13, 2015 4:43 pm

mushoo that sounds really cool.

I'm curious, why you did not stick w/ the Dglass 3D "HPX2-Max" dual extruder itself? In other words why did you feel the need to separate the motor from the HPX2-Max and mate it up w/ the chimera?

Also, you mention "The only improvement I can think of (beyond true support for flexible filament) is a servo-based nozzle retraction". Are you referencing the servo that comes w/ the HPX2-MAX?

Would you mind posting your custom mount and a pic of your device?

By the way, did you give the Cyclops much thought?

mushoo
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Re: Dual Extrusion at AOHQ

Post by mushoo » Mon Apr 13, 2015 7:54 pm

I went with the Chimera mainly because of it's single-body design. I probably could get away with using two hotends mounted into the HPX2-Max (lord knows I have enough random hotends now!) but my goal was rigidity, low weight, and easy calibration. The Chimera, being single-body, makes it really easy to calibrate the two hotends together - no wobble between the two.

The servo retraction I was mentioning wasn't the servo that comes with the HPX2-max - it was more a pie-in-the-sky dream, and wouldn't work with the Chimera. Basically, you have two hotends, and when one isn't in use, the whole hotend (or at least the nozzle) lifts up so that it doesn't drag around the model while the other hotend is active.
IMG_2132.JPG
HPX2 Chimera Mount
Chimera Plate D3D V3.stl
Chimera/HPX2 Mounting Plate
(148.96 KiB) Downloaded 65 times
Volcano Fan Shroud vB.stl
E3D Chimera - Volcano Fans
(37.39 KiB) Downloaded 64 times
Chimera Fan Shroud vE.stl
E3D - V6 Fans (not fully tested)
(55.75 KiB) Downloaded 62 times
For the fan shrouds, there's a thin beam connecting each half - this should be cut away before mounting. I'm using wood screws - I don't know the exact size - to keep the fans mounted to the extruder plate. The HPX2-max is mounted using, I think, M4 screws and nuts. I use 24v DC blower fans, like these http://www.amazon.com/gp/product/B00H8V ... UTF8&psc=1 -- these fans are very powerful! I never actually run them at 100%, as they'll make the nozzle temp drop by something like 20-25C at full blast.

There's some slots in the extruder body for zipties, to keep all the wires from floating around everywhere.

Also I added 3 extra pins to my extruder 2 snake cable coming from the electronics box, for the servo. The servo needs to be powered from a 12V rail, with a pololu DC-DC step down convertor to 5v. I use https://www.pololu.com/product/2107 . The servo also needs a PWM pin - I use one of the pins on the Motor Extension section of the RAMBo. Trying to power the servo from a 5V rail will cause a loooot of weird stuff, like jumpy stepper motors and other oddities - don't do it!

Dglass3D provides a Marlin firmware with the mods necessary for using the HPX2-Max, but it's definitely not meant for TAZ use out-of-the-box. I think it's setup for use with an Azteeg control board, no LCD, etc etc. I have my modified version that seems to be working mostly OK with the TAZ, but there are some odd little UI glitches (mainly with LCD text sizes).

inventabuild
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Re: Dual Extrusion at AOHQ

Post by inventabuild » Tue Apr 14, 2015 8:17 pm

Thanks for the files.

shaneckc
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Re: Dual Extrusion at AOHQ

Post by shaneckc » Tue May 05, 2015 6:55 pm

Any idea as to when the new Dual Extruder will be available for purchase?

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Orias
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Re: Dual Extrusion at AOHQ

Post by Orias » Wed May 06, 2015 8:49 am

We're testing the all-metal dually internally right now- you can follow the progress here: http://devel.lulzbot.com/TAZ/accessories/javelin/

We don't have a release date for you just yet.

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