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Thermoplasts can be recycled (by heat the material gets softened) (bins, bottles, bags, bottle caps, plastic cuttelry etc.)
Thermosets can not be recycled the Precious Plastic way (by heat it degrades and burns) (epoxy, urethane polyester etc.)
However most toys and kitchenware are thermoplastic so possible to recycle.
Precious Plastic will probably do further research to see if you can extrude PET.
LDPE beams, would require an extreme amount of plastic bags, something we were not ale to collect in this short amount of time
I used this for moment of inertia:
The variations are probably due to my measurement skills, deformation or non-homogeneous beams (although the seem pretty homogeneous)
Nice topic! Two low cost ideas I know from the forum:
Mold: some wooden plates to compress
Tools: regular Iron
Shapes: thin sheets, 3D object from sheets like bags etc.
References: Plastic bag topic
Price estimate: price of an iron, scrap wood
After many beams extruded I have some new data. All the beams were extruded with the extruder from the picture. And I used metal tubes which I mentioned in the start of the topic. While extruding I put a small wooden block in the tube (loosely fitting) to create a bit of counter pressure, resulting in smoother beams.
I updated the spreadsheet with my findings.
I did also stiffness estimations of all the beams finding higher speed gives more pressure which gives higher density of the beams which gives higher stiffness (E modulus)
Together with the visual qualities I figured that the most ideal settings for the extrusion are:
Temperature: 180 barrel and 190 nozzle
speed: 50 hz-138rpm
Gives an E modulus around 1.0 GPa
Temperature: 160 barrel and 170 nozzle
speed: 50 hz-138rpm
Gives an E modulus around 0.7 GPa
I was running low on material, (yes even in the PP headquarter). So, I did use a recycled PP from the industry. This material got less fluid while heated than the PP shreds I did shred myself. This can result in some variations in my research. How ever, the advised speed and temperature do still count for the extruder I used in the environment I was working
I did more tests and there I all the results in this spreadsheet.
I think that we can build on this spreadsheet to get a better idea of the different shredder capabilities. So feel free to add your shredder experience. And do not forget to fill in your shredder specs. I did never work with an open spreadsheet on a forum so curious how it goes.
Conclusion so far:
It highly depends on the type of products how fast you can process. Also experience has an influence on the results. So this is not a set average but an estimation of the shredder capabilities.
PP small items: 12 kg/h
PP big items: 4.5 kg/h
HDPE small items: 33 kg/h
HDPE big items: 9 kg/h
PET bottles: 7.5 kg/h
I do not get it. On one hand you are posting really counter productive, aggressive posts, on the other hand you are also building the machines (which look really good and professional build).
If you do not appreciate how PP works… just do not participate.
Same with ‘youtubers’ or ‘influencers’ some people love them and follow, learn and mimic how their idols behave. Some people do not like them and just ignore them.
Dave is not ‘the industry’. He is guy who wanted to change something in the world. His ideas are followed by many people. They do not need to do so. And since everything is open source, people are allowed to do what ever they want with his ideas.
Dont want to blend too much in this discussion, but after a quick check I found both on the PP website and the Bazar a small written text as a disclaimer:
Maybe it helps
@timhardex I will but right now it is messy and pretty empty. Will share later that later
Test number 4
Preparation time: 19.66 min
Prep amount/h: 1.55
Shred time: 4 min
Shred processing kg/h: 7.62
Test number 5
Preparation time: 6.3 min
Prep amount/h: 4.84
Shred time: 3 min
Shred processing kg/h: 10.16
Test number 6
Preparation time: –
Shred time: 15 min
Shred processing kg/h: 4.8
Remarks: done by somebody else. Bit slower than trained person
AVERAGE: 7.5 kg/h
Nice feedback, your are right on some points. About micro/nano plastics. I want to have the cleaning water in a pretty closed process. Only it water is really dirty it can be changed. Filtering the water can be done with something like sari cloth. Old sari, is really fine and also able to remove cholera bacteria. Read here more about this.
However, thoroughly cleaning plastic before shredding takes a lot of time and is more difficult because sometimes you need to cut it in small pieces in order to remove all the dirt. Also a great thing to do is to let the pieces scrub itself. Which works better with shreds than cut pieces of plastic. Otherwise all the pieces need to be cleaned by using cloth and wiping all the debris.
One thing to take in to consideration is that except glue and dirt, oil is also something to remove. Right now I think it works best to first clean the oil/ grease and then do shredding and washing (dirt/glue).
Also I know PP is on small scale, but I am researching efficiency to recycle as much as possible. Making it more attractive to wash also after shredding
Testing sieve sizes
As a part of the washing research, I did test different sieve meshes. I wanted to see which mesh is the best for further research. The fabric were different kinds of mosquito meshes. As result I figured out that the meshes do not difer much in filtering qualities: The plastic was caught but the dirt got through. It looked like plastic did stick less to on of the meshes.
After filtering with one of the three coarse meshes, I also filtered with the finest I could find. Although it caught the same size of plastics, the water stil had signs of microplastic.
Yes, you are right. But as mentioned.. this will be for a later research. It maybe needs another frame etc…
Together with Dave, I came up with the idea to shred and wash plastic at the same time. With siphoning technique you do not need a pump,although how I need to transfer the water back to the top by hand.
The first impressions are pretty good and it will probably further explored in version 4. However, due to time constraints, I am not focussing on this principle.
But it is nice food for thought.
Watch a short video here
I did use a 3D pen to fuse 3D printed parts into a bigger product. (yes… human scale). First we glued the surfaces together and with the pen we did melt a v-shape on the connecting edges which we filled with the 3D filament.
I don’t think it produces big enough for your application but maybe you can build a bigger version of a 3D pen from the extrusion machine
I would say it is the wrong direction (my opinion):
1) 3D printing filament needs to be really accurate in diameter. So it is hard the produce proper filament. (unless it will be a pallet-3Dprinter.
2) Also 3D printing has a lower finish than products from the PP machine. (you see lines)
3) 3D printing can only be done with certain materials like PLA, ABS and PET. HDPE (caps) shrinks too much so will never result in a nice product.
I think that degradation is a big problem with the beach plastic. It loses it qualities.
On an island in Australia I found some bottle caps which just fell apart when I picked them. Normally bottle caps are made of HDPE and are really though. So I think that with recycling those, the products get a lower quality.
First small scale sieve for sieving shreds. The mesh is a little bit too coarse so the shreds ‘leak’ a little. Searching for finer sieve.
I did some tests on washing PET and HDPE. I choose these two because of the high abundance of the materials and also because PET does sink while HDPE floats.
I seperated the materials on type and then made two equal batches of the material. One batch PET and one batch HDPE I washed before shredding and one batch of both materials I did wash after.
I figured out that washing before shredding is more time consuming but has some advantages. Especially oily substances are easier to remove on bigger parts by washing them with some cloth. Also it prevents the shredder from getting dirty.
However I think the best process is first cutting and cleaning the dirty products (especially oily substances) than shred than clean in water and then dry.
This is mainly because you can make this in a more streamlined process.
During washing the shreds I noticed some things that can be important in the further research (first picture):
Oil floats (obviously) so it is floats in the same layer as the HDPE.
PET sinks to the bottom of the container resulting that it gets mixed with the dirt.
Microplastics which get in the water should get handled and filtered with care. (see last picture
Right now I will continue on washing process optimization.
Open for feedback 🙂
Test number 2
Preparation time: –
Prep amount/h: –
Shred time: 6.5min
Shred processing kg/h: 5.70
Remarks: I could not keep up with the pace of the machine while it was shredding bottle caps. I was too slow with cutting the bigger objects
Test number 3
Preparation time: 15 min
Prep amount/h: 2.47
Shred time: 4 min
Shred processing kg/h: 9.26
Remarks: This batch was first cut and washed and than shredded. Therefor, the time is shorter while I shredded the same amount of plastic
AVERAGE: 9.02 kg/h
Also cleaning the shredder is pretty difficult without wasting/spreading the small dust
You can still use the microfibres in the process right? If molten, it is the same material as the shreds.
I’am now working on the process of shredding and washing and the microplastics are my concern as well. Maybe the guppyfriend is a bit too expensive in some countries.
During some research for my graduation I did found the filter capabilities of sari cloth (textile used mainly in India, Bangladesh etc).
The cloth is able to filter cholera, so I think it is also a good alternative for using as a shredded plastic container while washing the shreds.
Preparation time: –
Prep amount/h: –
Shred time: 60 min
Shred processing kg/h: 2.7
Remarks: Big PP products. Broke it down into smaller pieces during shredding process. Thick walled plastic is difficult to recycle.