Dual extruder designed for Ord Hadron

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Dual extruder designed for Ord Hadron

Postby jdm90 » Mon Jul 28, 2014 3:41 am

I have been into 3D printing for about a year and a half, with a few months of time out. I had gotten to the point where I felt I needed a dual extruder for my 3D printers. I wanted to try something different, but couldn't find much in line of what I was looking for, so I thought I'd design it with a certain set of ideas and see how it comes out. The parts are drawn from scratch, with some inspirations from a few different places.

It may look big, but in some ways, it's still reasonably compact. It's considerably smaller than two Wade's/Greg's, and considerably lighter than two NEMA17 or even two NEMA14 motors with metal gear boxes. One important place where it's very compact is the nozzle to nozzle spacing is 17mm, and both hot ends fit in the stock X carriage cutout without changes. Also, the width of the entire assembly is still a bit narrower than the stock carriage, and only slightly taller than the vertical part of the carriage. The usable X motion for dual extrusion is 196mm without making any changes to the X gantry.

This is only the second belt drive extruder I'm aware of, and the only belt drive dual extruder I've found. I did belt drive so that I can use a much lighter motor, and hoping I can still be lighter than a direct-drive setup with an equivalent amount of torque.

While a bowden setup would have been lighter on the carriage, I also wanted to use flexible filament. In the aim of using flexible filament, I lined the entire filament guide with PTFE tubing, the only gap being at the hobbed pulley, and that being a negligible short gap. I've even replaced the short tube in the top of the J-Head and with a longer that continues to the hobbed pulley.

The total mass of the extruder, including motors & hot ends is 600g. I had hoped to build it with no weight penalty over my single extruder using a metal gearbox, but that one was 450g. I think I can lose another 40g with lighter motors (not ordered yet) and smaller drive pulleys (on order) to make up for the lower torque. The extruder frame might be lightened some. A dual motor system with metal gearboxes would have been about 900g.

14762559755_b92a67926f_z.jpg


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Video in action on the first dual material part:

https://www.flickr.com/photos/34962649@N00/14576061370/

My slicing profile is still in need of plenty of tuning and experimentation, but the extruder system seems to be very sound, mechanically and electrically. The motion seems extremely smooth and solid. The drive system has an impressively stiff pull.
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Re: Dual extruder designed for Ord Hadron

Postby Atreidae » Mon Jul 28, 2014 8:46 am

Wow. Im a big Fan of this.
I tried doing an dual extruder setup using 2 Bulldogs and the whole thing was big and unweildy requiring massive modification to the Xcarrage that TBH in hindsight was poorly executed.
Ive now taken that machine back to a single extruder. But Im sure we could look at this with possibly two hexagon heads.

have you considered posting the designs on thingiverse/umagine as a WIP?
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Re: Dual extruder designed for Ord Hadron

Postby jdm90 » Tue Jul 29, 2014 1:57 pm

Thank you.

I have intentions of posting it on YouMagine. Maybe Thingiverse, depends on how I feel about them.

I'm pretty sure it's Hexagon compatible, I intended from the beginning to buy a pair to run this same extruder design on my MendelMax 2. I made sure I left enough spacing between barrels, it should work fine as long as you line the hexagons up flat-to-flat, but that's going from a measurement I was given by a Hexagon owner.

Then there's the documentation. It requires many of the parts to be assembled in a certain order. I drilled out the MK7 style pulleys to 6mm, and I think that's the biggest show stopper, because that was not easy with the stainless ones. I did find some brass ones in the past day. I might try that, brass drills very smoothly.
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Re: Dual extruder designed for Ord Hadron

Postby jdm90 » Sun Aug 17, 2014 10:13 pm

I have posted the current version of the design. I think I have at least 40 hours of successful operation on it right now. I'm very happy with how it's been running so far.

https://www.youmagine.com/designs/jd-du ... l-extruder

Save for minor omission here and there, I think that's all the information needed to build it.
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