Working on a filament recycler

I've been working on a filament extruder for the last few days, and so far my experiments with melting HDPE (old milk bottles) have been going very well.
Used some old copper pipe for the tube, and a large wood drill bit (steel) for the auger, wrapped some nichrome wire around the tube for heating, and secured with kapton tape.
I connected the nichrome wire to the extruder heater out pins of a gen 6 board, and placed the extruder thermistor on the extrusion end of the tube, and the 'heated bed' thermistor closer to the hopper.
Connected the board in repetier and I can control the heat to my device very well, and it melts the HDPE at about 130c. The thermistors seem to record the temperature very accurately.
The only thing is that there is a safety limit to power down the board when the bed thermistor goes above 150c. Obviously this safety limit is no longer valid for this application. How do I disable it? I am testing with HDPE at the moment since the lower melt temperatures make things easier, but if I want to work with PET later on then I need to go up to 260c+.
Will post more detail of my device and some pics soon. It needs a bit more work and refining, but things are going very well so far.

in the firmware there should be an option the change the bed max temp

Are those American milk jugs by any chance? Do you think soft drink bottles will have similar results? Please post pics of your 3d milk jug objects. Looking forward to them.

lazzymonk Wrote:
-------------------------------------------------------
> in the firmware there should be an option the
> change the bed max temp

How do I modify the firmware?

crendon2854 Wrote:
-------------------------------------------------------
>Are those American milk jugs by any chance?
>Do you think soft drink bottles will have similar results?
>Please post pics of your 3d milk jug objects. Looking forward to them.

Yes the plastic is milk jugs: HDPE, (recycle code 2) which melt at about 130c
I think I will have difficulty recycling soft drink bottles because they are PET, which melts at 260c, so the kapton tape holding my nichrome wire in place might degrade, anyone know what temp I can go up to with kapton tape?

Also, how do I get the filament to come out at a constant size? At the moment the device is extruding a good stream of molten plastic, but it is oozy and it changes size wildly. Maybe the temp is too high?
Will post pics soon.

I am very interested in this topic.
What kinds of plastics or blends give the best result?

Do they smell bad? Do they clog the nozzle?

How do you shred the plastics in preparation for melting?

I tried to cast molten plastics when I was little and I am curious about the results you are getting. I poured molten plastic from an elevated surface of a bridge under construction into a creek. The stream hardened like molten sugar and acted like a solid stick of plastic near the bottom. Or it turned into art when it was solidifying underwater. Don't ask me how I generated enough heat...

Melting plastic with sunlight may be a good idea for many reasons, besides the environmental concerns.

If I tried not to make this device mobile or compact than I would melt plastic on top of a tower and stretch it as it cools down so it is 3mm in diameter. Cooling it down with water may work...

Im also trying to build one of these but I'm working on a shredder first. What are you using for a shredder?

I am not using anything. I feel like instead of paying for filament we are going to pay for shredder blades now...

Maybe there is a way to compress plastics against a hot surface?
I feel like it is a good idea to do if you are planning to make a small factory out of this. But desktop filament maker would consume too much power/blades/time or everything at once, making it pointless.

Maybe RepRap users need to bus stock of the filament manufacturing companies?

I don't do shameless self plugs but this time I am going to make an exception. I am very excited about her! I just finished this a little over 2 weeks ago. Have a look at my baby!

I have recently showed it at Make's Hardware Innovation Showcase, the Bay Area Makerfaire where it was picked up by Revision3.com OmNom-Makerfaire, Hack Palo Alto, and Augmented World Expo.

Since Makerfaire this experience has been like trying to control a tornado! I can't stop getting asked to show it long enough to completely mod it! LOL
The entire bottom half is different from the picture there and much larger. But I am still using the thread-less die system.

My wife and I are working on the feasibility of taking this technology to Africa to help WoeLab make a sustainable filament resource out of their plastic pollution problem before I launch this machine by crowdfunding. They also have an E-Waste problem that they are working on solving and partially doing so by making 3D printers out of those old Compaq hulks! They are crowd funding on a french version of Kickstarter called Ulule

Mike

Excellent looking machine the rev3 video was crap though would have liked to see it crunching and working.

Ben

Would have been cool! Not my dime though..... It was Toyota's... might have notice they had a second or two of advertising space in it. Or was it the other way around?? LOL!

I need to get that video up on YouTube though but there is so many things to do and only one me! Kinda holding off on that one until I can get one up of OmNom directly feeding one of my 3D printers using recycled parts.

It's my personal holy grail!

Mike

***Edit*** There is a pre-makerfaire video up on YouTube. Although at that time I had just finished it and was going back and forth on if the grinding system was working reliably enough to run parts at makerfaire. Being it had only been complete for a few days at that point. I wound up not really running there though. Too many close calls because kids apparently can't read the word HOT! I did have one kid run up and start playing the switch panel like a video game and because not heated OmNom tried to fold itself in half! One of the reasons for the bigger extruder drive system.

Edited 1 time(s). Last edit at 06/07/2013 03:54AM by OmNomProject.