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helper
10/07/2019 at 09:00
3

Hey you all!

I had some personal deadlines and could not answer in june.
Here are the updated plans!

Right now we are working on Version 2! More safety and a better handling.
But still we need two persons to shred the plastic;)

peace
carl

helper
31/03/2019 at 08:58
3

hey,

first of all, we found some errors in the files for the casing parts.
we will fix it and then we will upload it again. sorry!

@ricardopinya
Tahnks!
mostly we shred pp. a few weeks ago i tested hdpe bottle caps. the thickness is up to 1,5 or 2mm i guess. at the moment we have no date about how much kg per hour. i think it’s a little bit more then the normal pp shredder produce.
We have to check how long they last. but you have enough material to resharp them 2-3 times.
mhm, we build the frame to put it on any 28″ bike. it’s not easy to find a design which fits to every bike, so we focused on 28″ because these are very common in europe.

peace
carl

helper
15/03/2019 at 19:28
4

and that’s the video!

helper
15/03/2019 at 19:20
6

whooop, we’re finally ready to share with you all our drawings, files, etc…

here are the blueprints!

helper
04/02/2019 at 21:41
4

thanks @timslab!

the problems you mentioned are the major problems we have with our precious plastic shredder. with our “new” design we are a lot better.
a little bit of dust yes, but not that much. for all i know the big industrial ones are producing dust too. we focused on getting the shredder as much leakproof as we could. the hopper is crucial, furthermore it’s good for the safety;-)

statically charged. it’s like the dust. a little bit but not in comparison to our other model. we are using a metal box for the collection box, so maybe this beneficial to “discharge” the plastic.how fast rotates your shredder?

peace
carl

helper
09/01/2019 at 17:21
3

@xxxoliverxxx @andyn
I’m very excited about a #piranhapeg mass production:-)

Cheers!

Carl

helper
07/01/2019 at 17:18
1

hey @leoroth
thanks! we are still working on a proper documentation. I think we will publish the video and the files during february. furthermore you can contact me personal via direct messages and i will give you some unpolished files, so you can start to work on that shredder!

much love

carl

helper
23/12/2018 at 12:48
5

hey guys,
@btmetz shared some photos of a high rotating shredder. we build one pretty similar – just smaller. This shredder is working great… even with a power of an bicycle! We have 4 rotating blades and 2 fixed on the casing. The blades are out of hardened steel. We focused on that design because it’s working more like the industrial standard, which is high speed (about 1100rpm). It doesn’t need that much power. Successfully we tested a motor with 0,3kW/230V and a 28″ bicycle.
We doesn’t made an exact comparison test, but we think that this design is working more efficient than the current pp shredder. Another good benefit is, that the plastic isn’t that much electrified. This was on of the main problems we struggled with the current pp shredder.
At the moment we try to simplify our construciton, especially the axle.
I’ve started a topic in the forum, but it’s been a few weeks since I posted something. But there will be a video in the next few months about the building time and the cad files are also nearly finished…

great topic!

peace
Carl

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helper
05/11/2018 at 11:06
5

For the shredding unit we also have considered two variants.

1. The fast one (about 1100RPM / 180-250W)
Pro:
– low torque fluctuation
– we have a working prototype
Contra:
– special cutting knives and axe
– very fast -> maybe more dangerous than a slow one

2. The slow one (about 100RPM / ~2000W)
Pro:
– we have a working shredding unit in our workspace (but with a big electric motor)
– less dangerous speed
Contra:
– a lot of power / torque is necessary
– fluctuating torque -> not good for any drive source
– heavy -> a lot of lasercut parts

We comoared both variants with the proporties of a bicycle. It is possible for a person to get 200W out of a bike and with the right transmission we are able to reach a RPM over 1000. A power of about 2000W respectively a very high torque is more complex to realise on a bike.

With this comparison we decided to work on option 1. Furthermore we ththoug that it would be safer because to get the high torque for option 2 it is necessary to have a flywheel and imagine something gets stuck in the shredder and the machines stops to turn, but the energy is still there. So maybe the chain jump or the belt break like the people in Shanghai experienced with.

@siemenc i do not think that this is necessary. With normal waste we do not have any problems to shred it. It would make the machine heavy and more difficult to stop

The pictures show the principle of the shredding unit and our first protoype with an electric motor (230V/250W) in a case out of acrylicglas and aluminium.

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helper
05/11/2018 at 09:00
2

Hey @adelef
Thanks!
We made a completely different blade design and we are working with a high RPM and low torque. More or less it is exactly the opposite of the ‘normal’ precious pladtic shredder.

We precut the plastic in pieces that fit in our hopper. Until now we just have tested PP and i think the max. Thickness was about 2mm.

I will write a detailed post about the shredding unit this evening. With some pictures, drawings and facts…

Peace
Carl

helper
04/11/2018 at 23:38
5

It all started with an analysis about what does the machine have to do:
mobility -> has to be carried on a bike
human powered / independently from electricity -> we transport it with a bike so we also have to create the energy to shred plastic
lightweight, compact and solid -> not that easy:)
maximum safety priority and easy to use -> we work a lot with kids or youth groups. So everything has to be safe and simple to understand.
shred plastic efficient
leakproof

Solving approaches of the main parts

Mobility. Here we considered 2 options:

1. One bike firmly connected with the shredding unit
pro:
– one single functional system
– super mobil, everthing is on the bike
conrta:
– in case the bike is defective the shredder is not working
– heavy bike

2. Modular shredding unit you can connect to every bike
pro:
– the shredding unit without the bike is compact to store
– people can use their own bike to shred plastic
– some people are smaller some are bigger -> we are able to change the bike for differnt body sizes
contra:
– no process gurantee -> every bike is a litler bit different. We can’t be sure that ther shredder is working with ever bike.

We decided to make option 2 with restriction: Only 28″ bikes

This is one of the first sketches:

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helper
14/08/2018 at 23:45
0

and another two

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helper
14/08/2018 at 23:40
0

@fabirihotmail-com
here it is. the most importand rules to design our nozzle are:
1. make sure you can heat it up nice and quickly
2. make sure you can fix the mould on a fast and save way,

we don’t use threads because it takes a long time to get the mould ready on the injection machine. that’s why we are using a car jack to press our moulds against our redesigned nozzle.

here are some pics:

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helper
14/08/2018 at 23:31
2

thanks to all of you!

helper
02/08/2018 at 21:12
4

@anne-barbier
When everythin is nice and smooth we are about 30 clamps during one hour. But  we are using a car jack to press the mould against the nozzle. That’s a lot faster then threat. and we have less waste because our sprue shorter.

@andyn
Wow! Good Work!
Do you have any daft angel? When the mould gets warm, the clamp is easy to get out.

helper
31/07/2018 at 22:32
4

Yes we will share the drawings. Licensed under a CC BY-SA 4.0

These are the files we used. pick what you need.

Peace

Attachments:
  1. piranhaclamp.zip
helper
27/07/2018 at 15:31
3

Hey, sorry to all of you! The past month I was travalling through Kenya without internet…
I have just arrived… for these two points i need some time 😉

1. I’ll have to check what I can share with you. I’m sure we will upload the files. But Kunststoffschmiede is a group of a few people and I have to check if the majority agrees with it.
2. Translate the technical drawings into english

peace carl

helper
30/06/2018 at 09:02
2

Take some good stuff with you from your workspace;) we can trade with #piranhaclamps :)))

peace
carl

helper
24/05/2018 at 07:34
1

@davehakkens thanks!
@andyn i’ll try to upload a step file from the clamp itself.

that didn’t work. any suggestions how i can upload it in the forum.
furthermore i can send you the file via mail.

helper
23/05/2018 at 10:26
1

@mattia-io hehe thanks man!

ahhhh! copy&paste would be to easy;) i’ll send you an email!

there wil be a limited edition for the bazar, soon;-)

helper
23/05/2018 at 09:35
2

@imhu thanks!
well yes, we didn’t test other types:) but for all we know, pp is one of the most flexible types of plastic.
maybe we will use an external tool to brand. currently we are testing the dremel versa tip. in this case we would be free to try other types. but for every clamp it’s another step.

we don’t cool or preheat the mould. all natural:)
in the beginning the clamp shrinks a lot and it’s a little bit difficult to demould it. after some injections the mould is a little bit cozy, then it’s very easy to demould the clamp.
as a generel rule you can work with 2-3% of shrinking. it also depends on how much pressure you give.

peace

helper
22/05/2018 at 22:52
3

The last steps we have to make is the engraving of the plastic type (we purposely left it out to test if PP is the right plastic) and to find the fastest way to open and close the mould

.

I hope I could explain it to you well! Feel free to write every question or remark in this topic;-)

Besides we are testing all use cases we can imagine;-)

#champagnerclamp: Check!
What comes next?

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helper
22/05/2018 at 22:50
6

First they milled a positiv of the clamp out of copper. This copper electrode was used to burn (EDM technique) the form of the clamp into the metal mould. Here are some pictures of the production.

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helper
22/05/2018 at 22:48
5

In the meantime, we have been able to establish contact with an injection molding company. The Schicktanz GmbH: 70km away from our workspace and very supportive.

They have their own workshop to build high-end moulds.

It ended up that they made the mould for the #piranhaclamp for free. Thank you!

Even if the mould was for free, it was a huge charge on our team to supply the right files. It is quite different if you make a testmould with plexiglas or give something in order, which is worth several thousand euros.

We made the last prototypes with the 3D printer.
And after a few hours of discussion we decided us for one design and made all files ready for Schicktanz GmbH.

Here some specs:

parting line: central

draft angle: 3%

engraving depth: about 0,5mm

curves: 0,5mm radius

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helper
22/05/2018 at 22:46
9

As well as the first clothes peg, we made our first prototypes in plexiglas/acrylic glas (You want to know how it works? Watch the turorial on youtube: https://www.youtube.com/watch?v=24ECE3VL13k)

We tested it and it worked. Yes it worked:) Such a good feeling!

But we also had to notice that plexiglas isn’t the right material for the mould. Not in the long run. Because in the current design of the #piranhaclamp we have this tiny bridge from the inner circle to the outside. This bridge is too weak, so it easy breaks when you demould your clamp.

At first we had a working mould and a bad design. Now we had a bad mould and a good design. It did not feel like failure, but we still had not achieved our goal…

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helper
22/05/2018 at 22:42
5

So our main advise in product development: Failure is essential.

We made the spring thicker, thinner, shapeless and even, but it did not help. She was still breaking. So we came to the realization that we need a completely different design.

Anna made a research about clamps. There’re so many way’s of clamping your laundry. We never would have thought that:)

We wanted to have a clothes peg with just one part and Anna found a design on thingiverse:) https://www.thingiverse.com/thing:339768

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helper
22/05/2018 at 22:39
6

In summer of 2017 we finished building the injection machine, and made the first tests. One of these first test was the clothes peg.

We tried an old design from DDR. We replaced the metal spring with a plastic spring, but it didn’t worked out very well. The spring fractured quite often:( So sad…

Nevertheless it was a success, because we learned a lot about plastic, made an undercut injection mould and presented the first try with many other fancy community creations at the DDW’17.

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