Dual Extrusion at AOHQ

This may be a bit premature…

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

Not yet, but definitely on the todo list. Files will start appearing here, as we have them:




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

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.

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.

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?

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.

Chimera Plate D3D V3.stl (149 KB)
Volcano Fan Shroud vB.stl (37.4 KB)
Chimera Fan Shroud vE.stl (55.7 KB)
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/B00H8VV0XK/ref=oh_aui_detailpage_o00_s00?ie=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).

Thanks for the files.

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

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.

Reading up on all the progress with y’all’s dual extruder. Pretty cool stuff. I was wondering… have y’all considered making mounts to place somewhere on the frame of the printer (one of the rails on top maybe?) and moving the extrusion motors there to get them off of the print head set up? An idea similar to what the Ultimaker (2?) has so that y’all can reduce a bunch of weight off of the whole set up to get some higher speeds, but still keep sharper edges by not throwing all of that extra weight around? Just an idea, I’m not sure how plausible it would be with the open design of the TAZ…

I made a dual all metal hot end tool head for my Taz 5. You can see it here: http://www.thingiverse.com/thing:987570

So far, I’ve only printed the one dice.

I still have to fine tune it. I noticed that when a job starts and the extruders are primed, When extruder 2 is primed, it moves slowly, and the print surface also moves. After that, it works normally. Does anybody have any idea why that is happening?

Never mind – I fixed it.

Mind telling us what the problem was, and how you fixed it? Useful if someone else comes across this later.

It appears to be an issue in the TAZ 5 firmware. I checked the pin settings and variables in pins.h, and they all looked good. I couldn’t find anything obvious wrong with it when I looked through the code.

I decided to fall back to the TAZ 4 firmware as a test. After making adjustments for my toolhead, it appears to be working beautifully, so I’m using that.

I successfully printed a nice 2 color frog. You can see a picture of that in process by following the link above. The frog printed very nicely.

It appears that the problem I posted about earlier occurs when I hard code the dual extruder offset into the firmware.

I had a problem with Cura ignoring my offset settings during slicing, so I coded the settings into the firmware on the taz 4 firmware that I have been using, and was able to duplicate the issue.

Does anybody have any idea why this is happening? Code below.



// Offset of the extruders (uncomment if using more than one and relying on firmware to position when changing).
// The offset has to be X=0, Y=0 for the extruder 0 hotend (default extruder).
// For the other hotends it is their distance from the extruder 0 hotend.
#define EXTRUDER_OFFSET_X {0.0, -0.30} // (in mm) for each extruder, offset of the hotend on the X axis
#define EXTRUDER_OFFSET_Y {0.0, -48.6} // (in mm) for each extruder, offset of the hotend on the Y axis

Hey Lulz guys, are the only machined parts on this the lower bracket, hex mount plate, and the corner pieces on the bed? Any idea how final of a design that lower bracket is? I’m considering biting the bullet and making my own because I have a few projects that I could really use dissolvable supports for, but I no longer have access to a CNC mill so I’ll have to pay someone else to do it and am hoping to avoid a bunch of expensive revisions. :wink:

Of course looking at the BOM it looks like you ordered 500 sets, so it must be somewhat finalized.

Hello all,

Here is a couple of pictures of the V2 Dual Extruder and the V2 FlexyDually.

I-T-W.com had a few of the blemished condition brackets available. They’ve been out fo stock for a little while, but they may get more in. You can’t have mine though!