BDan
April 5, 2015, 6:07am
29
Hi pomaer! we tried the idea of using pellets in a printer instead of filament few years ago in our lab. It was a monster DIY printer intended to be the next home appliance… We quickly realized that moving a hopper and all the weight around was not an option. We also realized that pellets bring problems with air and filament is still the best way to go. It’s light and the print head can muve faster, and the printer will endure less stress from the head changing direction, and it’s consistant. Then we decided to put a hopper and an extruder in the top back side of the printer and the filament produced would be uneven and cause many problems, and that it had to be dried before we feed into the printing head. Our conclusion was that instead of trying to build a do-it-all thing that does nothing right, it’s better to do things with specific jobs as good as possible. Often times, keeping things simple and sturdy is your best option. It’s still possible to have a crusher and an extruder dirrctly integrated into a home appliance sized 3D printer. It would look something like a stove. But there are so many parameters to watch out for… Unless it’s a super reliable closed loop feedback system that monitorizes and decides for best parameter by it self, most users are not Makers and will lose patience… now for the heating of the shredder blades, I think it’s better to freeze the plastic before you mash it, it becomes more brittle and snaps easyer when it’s frosen hard. I think heating it up even a bit will just make it bendy-er
MB3D
April 5, 2015, 10:40am
30
Freezing could have a quite positive effect on the crushing of parts. Did your pellet extruder contain a filter and did you use an extruderscrew or just an auger one? One of the most important features that DIY pellet extruders are missing is a real extruder screw that compresses the pellets by getting smaller (the space where the pellets are gets smaller). I thought about a design for a printer, that doesn’t move the printhead, I’ll explain that later. -Marius
This is all interesting stuff. I think that there are many challenges here and it’s best to separate out the issues. Firstly, I think we need to decouple shredding from extruding.
Shredding has its advantages, which are mainly environmental, rather than financial. Realistically, I think a semi-centralised shredding function is most practical.
Extruding is financially very attractive. As Marius says, granulated plastic is cheaper than filament, except that the actual difference in cost is enormous. I heard that the World market for filament is less than 100 Tonnes. The market for granulated plastic is in the Millions of Tonnes per year so the potential difference is very high - think 1-2 Cents per kilo for granulated plastic. Now THAT concentrates the mind!
There are one or two granule-fed print heads surfacing. TBH, I think it’s only a matter of time before the technical challenges are met. Perhaps it’s been done already.
cheers,
AndyL
Pot8oSh3D
most of those machines don’t have a closed loop control of the filament… What they all lack mostly are a sensor that measures the filament width and then adjusts according to that.
Modular Filament Extruder by diegotrap - Thingiverse is close to cheap and good enough, all its missing is this one Filament Width Sensor - Prototype 2 by flipper - Thingiverse
and then you simply adjust the speed of the puller so the diameter matches… it will take a bit for the width to be stable, but once you reach that stage you simple cut the filament and the first bit you can cut in small bits and melt them again
going to build it over and after summer…
BDan
April 5, 2015, 4:24pm
33
You’re right, we used a drill bit for the proof of concept and we should have tried with a real screw. We thought the best way would be twin screws heated by induction to keep the temp stable. There are some neatly designed twin screws that take care of air bubbles, evenly mix in pigments and other stuff like carbon microfiber or nanotubes, etc… But then again, extruding the plastic is not enough. Pulling, stretching and cooling is a fine balance of parameters for best results with each plastic. That’s for filament usung 3D printers, I can’t wait to see your design… Cheers!
MB3D
April 5, 2015, 4:39pm
34
@Pot8oSh3D @BDan I thought about anot extruder design somewhat similar to the STACKER 3d printer. You can change the stacker-hotends depending on the material that you want. There would be three heat zones in the extruder which is will explain soon. Sadly I wasn’t at the PC since todays morning morning. -Marius
MB3D
April 5, 2015, 5:37pm
35
Here is the explanation. I hope everything is readable.
The following is the text on the picture on the left side:
(1) Sliders for extruder
(2) ramaining panel for mounting the extruder
(1) “feed”-area where pellets get inserted into the screw; Temp -> 25°C (no heatsource in this area)
(2)“compression”-area where the pellets get heated to glass transision temperature and get compressed to form an air-free paste, the screw’s geometry is made for this; Temp -> 60-100°C (depending on material)
(3) “extrusion area” selfexplaining; Temp -> 180-300°C (depending on material)
//The small brown connectors between the bigger blocks that determin (1) to (3) are heatbreaks just like in nearly every hotend to ensure, that the possible 300°C from the hotend do not get up to the “feed” area. The screw is obviously out of metal and therefore conducts heat very good.
-Marius
yes i do i meant that use the polymer to make the spool into the Abs or Pla filament print with it
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MB3D
April 5, 2015, 5:58pm
37
So you mean that you want to turn the spool into filament ? This isn’t possible since the spool is not made out of ABS or PLA if you want those filaments. And if you want polycarbonate filament (because the spools are out of polycarbonate) then you have to shred the spools, melt the granulate and extrude filament. The machines necessary for that cost way over 2000€ if you want a good quality filament.
Beside all that you will then run into the problem of printing with Polycarbonate.
Polycarbonate has to be extruded at ~300°C or more and requires a heated bed with a temperature of 120°C. I bet not even your printer archieves those temperatures.
It is not worth it to buy those machines just to recycle some spools.
-Marius
BDan
April 5, 2015, 6:36pm
38
Just to let everyone know, at the Sensorica lab, we have precedent of Co-financing equipement and all the legal structure around that. For example, the MH3000 from Ord Solutions (Toronto) is a pro-level FDM machine, 30 x 30 x30cm, 5 heads can heat up to 450℃, heated bed, full metal parts and framing, etc, please check the specs: http://ordsolutions.com/our-3d-printers/mh3000/ . It costed 4200$ and we are 12 co-owners. I invested 1500$ and I’m the main operator. 20% of all revenue from commercial activity goes back to initial investors (according to equation) until printer payed + 20%. Operators make the other (up to) 80% from commercial activity and pay back 5% to use FabLab space and infrastructure. After it’s made profitable, these %s change and some ownership is passed to the FabLab Custodian to benefit the whole community and make fair use for Open Source projects (because we’re a FabLab). Many more details and tons of brainstorming for this particular case but it’s a viable way to crowd-finance expensive equipement among hubs that would benefit from them. We can do the same exercise here and together we can afford some serious shredding and extruding machines. Thaks for considering seriously
1 Like
you can use polymers on polymer to turn things into other things
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MB3D
April 5, 2015, 11:46pm
40
Do you have any idea on how chemistry works ? You can’t just put some polymer on another polymer and by magic you get filament with a perfect diameter. Even if you dissolve the spool or anything like that you still have to form the filament.
Please try to learn some english, i do not want to insult you, but i have an incredibly hard time reading your comments.
-Marius
BDan
April 6, 2015, 12:27am
41
Yes, fine tuning parameters is a narrow window, and it’s hard to keep exterior conditions constant… for ex: you walk by and the air you move will affect the cooling speed of freshly squirted plastic and affect the filament diameter and evenness in that area. Ever so slightly but you have to consider. I think 5% diameter variation is the best you can get, 10% is acceptable but higher than that is unacceptable for commercial distribution. In our lab we’re all about sensors (Sensorica) I understand the importance of monitorizing and automation and it’s really not complicated. For domestic use everything goes but once you get into cimmercial use you bump into regulations and you have to make sure your equipement is safe. You also bump into the responsability to provide a quality product. This is why I’m looking for a commercial grade extruder. DIY is just reinventing the wheel and it ends up costing the same in materials, special parts and time spent wondering around. There are some pretty neat machines out there, closed loop feedback (sensors), etc, respecting safety requirements and licenses, etc, help me find the best choice for our purpose… Please
I am American I just sometimes don’t write a word down correctly. And you can I have chemists around me and you can make a polymer that can turn a polymer into another polymer. I don’t really care what you think about me and my words, but you can manufacture the spool into a polymer and then manufacture some kind of plastic and It wold really help everywhere to go green.
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MB3D
April 6, 2015, 3:00pm
43
Kevparang, the topic is about what you do with your empty spools, please explain me how you turn a spool (which is allready a polymer, to be specific it is Polycarbonate) into any other polymer like ABS or PLA just by blending it with some other polymers.
The key discussion in this topic is how to recycle spools. Is there a method with that you produced filament or something similar just by using a spool as input material ?
I have no problem with it, if you do not want to explain your words so that I or others can understand them but i guess it would help everyone if you make clear what you want to say and how that benefits others.
-Marius
okay forget it just recycle them I dont care Marius just do what you want to do
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Hey all,
We are in the middle of setting up a spool recycling program here in the UK. We have already connected to a few retailers. The basic idea is, you send us your box of empty spools and we purchase them off you…
For those outside the UK, unfortunately, at this present moment we cannot pay for postage from outside the UK, however we will still credit your account with a set amount per spool.
The spools will be turned in to circular products and reused rather than sent to landfill. We to vet members wishing to join the program and there must be a set of spools with a minimum amount in the package to make it worth while. Nether the less…
Interested? Like to find out more? We are especially interested in Makerhubs and Retailers specialising in 3D Printing tech joining our program.
Contact me at info@fila-cycle.com
Thanks
Scott - CoFounder at fila-cycle.com
2 Likes
Hi Muckychris,
If you don’t mind me asking, how much do you sell them for? Thanks!
