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Shredder 2.1
- This topic has 35 replies, 23 voices, and was last updated 3 years ago by
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Hey everyone
As you might know we are working on V3 of the project, here you can have a look at our full plan. This time our focus isn’t on re-developing the machines but trying to get the most out of them. That said we do have a few tweaks and things we could improve on the shredder. Mainly making it easier for the plastic to be pulled into the shredder so you don’t have to do it manually. And looking for a way to make it easier to change/clean the mesh. This wouldn’t be a full update but more of a hack. So if you already build the machine you can simply upgrade only a component (the advantage of a modular build 🙂
@morrentrading is going to help us with his expertise in building shredders. If you guys have any updates/hacks/suggestions let us know.
Our first try-out. A different blade-set
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Wow! Nice to see further improvements on the machines! Looks amazing!
However the exchangeability of the shredder blades ends when welding the shredding unit, right? This leads to the question: Is it necessary to weld the stainless steel case of the unit in the first place? Aren’t the 10 screws enough? 😀
EDIT: Wow, I’ve overlooked how the shredder design is even more amazing than I thought before. 😀
Wow, that looks cool.
Thanks for sharing !!!
Have you tried them out? How big and what are the differences?
Do you have CAD-files available for those parts? We are about to order and if these knifes are much more efficient, I would like to go for them of course.
Cheers from Cambodia
Daniel
Awesome! I would like to see those in action! I have my parts and havent start building my shredder yet but if this works I can modify my blades or shape it something this this design
@davehakkens have this been tested yet? If so what is the outcome?
I do have my parts for the shredder
Can i just simply modify my existing blades to look this this one?
Pls how can I get these blades and the other accessories from your location to Nigeria @davehakkens
I agree that it would be nice for something on the outside of the blades to grab onto the material. I am working on a new set of blades for my machine and I may give this a try.
Another thing that I noticed with mine is that sometimes material likes to get stuck between the blades and spacers. I’m thinking that next go-around I may add some cuts on the spacers to help grab material and drag it down (attached)
I also agree about the mesh, it gets clogged easily, and on my setup it’s really hard not to not get material everywhere.. So I’m gonna make a hopper that goes underneath, and I’m even thinking I may attach a shop vaccum to the bottom to help draw material through. I found on mine that the material is definitely chopped up smaller than the mesh is, but it just doesn’t want to go through the holes easily.
I’ve also posted an update on my original thread.
http://onearmy.world/community/forums/topic/modified-larger-shredder/
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Hello everyone. We got in touch with Peter Hinten, an engineer from the Netherlands who wants to help out with the shredder update. We discussed about the things that could be improved and he made a new CAD model based on the previous model + feedback. Have a look at the attached .pdf below and turn around the 3D model in Grabcad (click load in 3D viewer to turn the model around.)
What do you think, suggestions tips feedback?
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Wow, that’s a serious upgrade there! I love it. Especially the safety improvements are great. I’d love to built this one!!
@davehakkens we added an encoder to detect stalling. But a overcurrent protection shall do the job too.
Nice work! The guys at Precious plastic ukraine have also been modding the shredder and they’ve made super minimal version. @khlebnikov317 You should share your plans! 😀
@davehakkens have those new blades been cut by waterjet? Look really great, smooth
The Emergency switch is a really good idea, when I bought my electronics I included one, should be positioned for very easy access.
Thumbs up for the frame/leg mod.
The “Knife area is decreased to avoid cutting large part in one time”, does it mean that the knifes are made of thinner steel? That would mean more parts.
Good to read your feedback! The amount of knifes is the same, the thickness also. The curve at the end is smaller so it would chew off smaller bits. This to avoid blocked engines and too much stress on all components. The limiting factor timewise is the sieve anyway
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I love the look of the new blades and the design changes look like great improvements! I am curious as to why you did not go with a 3 or 4 blade rotating knife? Every other shredder I can find uses this style. Like the ones below. I am not criticizing, I merely want to understand. The machine is well designed so I am sure there is a reason! Off the top of my head: cost of materials – a two blade knife uses less material and/or rotating mass is less as well, also most other shredders are dual axle and thus more complex – so minimizing complexity. Anyway, I drew up a few blades that would fit right into the current housing. I mostly modified the original design. Any feedback on these would be great! Thanks! Again, love the machine!
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In the PP hq I worked a lot with the shredder.
I made two improvements:
Hopper
The hopper is now straight so the material needs to be a bit smaller but therefore it gets less stuck
With the elastic rope you can create tension on the press stick, resulting in shredding without needing to press all the time by hand
Coupling
With shredding PP we had a lot of problems with the axle connection so we made a coupling of 2 plates welded to the axle of the engine as well to the axle of the shredder. The 2 plates are connected with 4 bolts so it is still possible to take it apart.
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With a stronger coupling we sometimes have problem with plastic melting instead of getting shred. The blades are not extremely hot by friction so the plastic melts by compression. I think it is due to the spiral shape of the blade set up. All the plastic is moving to the end resulting in two blades cutting the plastic (see drawing). To resolve this I think half of the blade setup should be spiral and the rest should be more spread so different blades are cutting the plastic all the time.
@agile, what do you think about this?
Because it takes a lot of time to take the whole shredder apart, I did not do it yet.
Is someone willing to try this? Otherwise i will do this probably in the future.
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Have you tried arranging the blades in a chevron pattern, one half a mirror image of the other so that material is pulled towards the centre?
I read a lot about people having to push material (by hand or with a stick etc.) into the blades. I don’t have personal experience with the PP shredder, but I have built a twin shaft shredder and I have no problems with this, it just grabs anything and feeds it through even though the blades are half the size and the teeth much smaller. I have an interlocked lid on my hopper that only needs to be opened to add more plastic. The only added complexity is that you need a pair of gears to link the shafts.
We did. But the material was not always getting into the shredder. The spiral seems to works better but results in jamming the shredder when too much plastic is shredded at one specific spot
Hi everyone! I write from Argentina! I am working on a new design attempt for the shredder. I am thinking in somethin like this…
where it is used one or two big blades and a lot of small blades and it is not necesary a mesh. The size of the particles is fixed by the small blade size. Did you already think in something like this?
I am trying to make the shredder cheaper because here in Argentina there are a lot of people interested in start with plastic recicling but build the machines are not cheap enough.
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@mathijsstroober Nice! How exactly did you set up the blades there? Just randomly or do you have a pattern?
@flo-2
At the workspace it is now a spiral shape. But my idea is half spiral- half random. So the plastic is transferred to one side of the shredder and then shredded by multiple knifes. Maybe we can check this soon. But it takes a lot to take the shredder apart.
HI, mi name is Luis, im from mexico.
im trying to build the shredder but on my autocad inventor drawing found a gap between the rotating blades and the small and big fixed blades.
the total lenght of the rotating blades assembly is 148 mm
The total lenght of the fixed knifes is 149mm
Taking this in consideration there would be a gap of 1mm horizontally between fixed and rotating blades.
Please let me know if im doing something wrong.
thanks in adavance for your help with this issue
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Hello @luisgamez
That’s correct, there’s a small gap between each rotating and fixed knife, and that’s how it’s intended.
In a perfect world, 3mm thick metal is 3.000000000000000mm thick, in the real world, 3mm metal is something around 3.01mm thick. Due to this, a small gap is required to avoid friction between the knives or having a shredder that doesn’t spin at all.
Regards
Hi Dave! We are a group of basicyear students from the Gerrit Rietveld Academie making the shredder at the moment. The thing is that I cannot find version 2.1 anywhere to download (the precious plastic website is only in v2.0!) Thank you!
@basicyearrietveld
Hey there, it’s all in the Download Kit!
In the “BUILD”-Folder you will find two folders: One for the Shredder itself (V2.1) and one with the Shredder Upgrades (Hopper and Sieve). 🙂
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