New and different dual extruder idea

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Slipshine
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Re: New and different dual extruder idea

Post by Slipshine » Mon Oct 26, 2015 7:26 pm

Tim I really like the Idea. I was working on a similar but the carriage would attach to the separate heads with a spring loaded taper pin for strength and repeatability. A small solenoid or electromagnet hooked to a spare m-code to pull it out.

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Tim
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Re: New and different dual extruder idea

Post by Tim » Mon Oct 26, 2015 10:02 pm

Slipshine wrote:Tim I really like the Idea. I was working on a similar but the carriage would attach to the separate heads with a spring loaded taper pin for strength and repeatability. A small solenoid or electromagnet hooked to a spare m-code to pull it out.
I was hoping that the magnets would preclude the need for a physical latching mechanism with solenoids. But if the magnets prove to be completely unworkable, I plan to go that route. I haven't even considered a parts list yet for that contingency. What did you come up with?

Slipshine
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Re: New and different dual extruder idea

Post by Slipshine » Tue Oct 27, 2015 8:08 pm

Im sorry I had not put one together either. I have access to a substantial machine shop so I was planning on burning a weekend and making what I needed.

nirfriedman
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Re: New and different dual extruder idea

Post by nirfriedman » Wed Oct 28, 2015 12:35 am

mharter wrote:
Tim wrote:
nirfriedman wrote:If you go for two separate heads, why not have them on two separate belts? as far as I can see, you can put two belt drives in parallel (add one behind the current one) and have one carriage with longer extension backward. The price is that you have another motor and need firmware changes. The benefit is that you avoid the headache of reattaching heads which seems to me highly non-trivial.
I think rewriting the firmware for two separate X steppers is highly non-trivial. There's also the point that very few controller boards support that many motors (the Fastbot bbp1s that was mentioned recently by PcS is one exception, but I don't have one of those). I guess I've concluded that just about any way you do a dual-extruder setup, something is going to end up being non-trivial. The way I'm trying to do it, though, has a pretty low overhead on extra hardware. Although once I've gone halfway through prototyping it, I may very well end up agreeing with you. I won't know until I've tried it.

There is actually plans for a dual carriage bukobot on their website: http://bukobot.com/creating-a-dual-x-carriage-bukobot. firmware changes and all. This modification uses the dual belt system. I have a Fastbot bbp1s on order just for this occasion (when I get to it that is). The dual carriage with dual belts is a ver simple implementation. If only the M2 frame was wider by some inches to accommodate two carriages. I don't feel confident the M2 would handle the faster print speeds of the Fastbot as the y axis moves via the bed. I would be worried that taller prints would get wobbly and break off from the quick back and forth jerks of the high speed board. Interesting times ahead!
The video looks good. If the firmware issues are solved, this a much saner solution than current dual extruder heads.

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Tim
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Re: New and different dual extruder idea

Post by Tim » Tue Dec 08, 2015 4:54 am

IT LIVES!!!

http://opencircuitdesign.com/~tim/videos

I have validated the concept, and it really works! I am calling it the "M2 twin", as it has twin independent single V4 extruders instead of one big chunky dual extruder. Two extruders, one belt.

There is still a bit of calibration, testing, optimization, and maybe some minor redesign as well, but basically it all works as advertised (at the beginning of this thread).

I did discover, unfortunately, that if you let a hot nozzle drop out of the mount plate and give the zebra plate a scrubbing, it quickly melts the zebra plate surface. . .

But I also discovered a not-very-well documented feature of Simplify3D that allows (in effect) a different tool change script to be run when switching from right-to-left and from left-to-right.

I'll document more in the days to come, but I wanted to get out this tantalizing tidbit of a video today. . .

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Jules
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Re: New and different dual extruder idea

Post by Jules » Tue Dec 08, 2015 5:00 am

Oh, BRAVO Tim! Man, that looks sharp! (I want!) :D

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Levi8than
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Re: New and different dual extruder idea

Post by Levi8than » Tue Dec 08, 2015 5:19 am

Wow. Is it just me, or was that really fast from idea to prototype?
What did you go with for grabbing the carriage on either end? I had assume magnets wouldn't hold well enough. Did you just prove me wrong?

... I want full plans so I can modify my own now. :)

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Tim
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Re: New and different dual extruder idea

Post by Tim » Tue Dec 08, 2015 5:32 am

All will be revealed, shortly. Plans will be made available. Write-ups will be more coherent, and videos will not be so dark (also I need to re-crop the last video, as I didn't notice that I cut off the bottom for the last half of the video. The original video has the full picture, and I'll re-post it tomorrow).

Also I will post the video of the epic fail in which the nozzle dropped out of the mount plate and melted the top of my Zebra plate!

By the way, although there is some stringing evident in the videos, I would like to mention that I ran that test with NO retraction whatsoever on either extruder.
Levi8than wrote:What did you go with for grabbing the carriage on either end? I had assume magnets wouldn't hold well enough. Did you just prove me wrong?
Yes, I did just prove you wrong. However, it wasn't a sure thing at all, but I got pretty lucky with my guess of the forces involved, plus the availability of magnets in just the right size, and it all just sort of came together right.

Before you start jumping into making your own, you'll want to read through my (yet to come) instructions and notes. There are a few tradeoffs involved, although I think that overall it comes out as a big win over the monolithic dual extruder. But I've only been running it for a total of about five minutes total, so it has a ways to go to prove itself.

Vandal968
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Re: New and different dual extruder idea

Post by Vandal968 » Tue Dec 08, 2015 7:07 am

Tim, wow! Brilliant.

VERY nicely done.

cheers,
c

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Tim
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Re: New and different dual extruder idea

Post by Tim » Tue Dec 08, 2015 3:05 pm

I have re-cropped the video so that you can actually see what's going on for the whole video. Also I uploaded the epic fail video.

http://opencircuitdesign.com/~tim/videos

Photos will be uploaded soon, and I'm going to start a new set of web pages on my site dedicated to MakerGear M2 projects.

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