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V4 Styrofoam Workspace [Melting]

This topic contains 1 reply, has 1 voice, and was last updated by  Carolina 5 days ago.

Carolina caroespinozaj

V4 Styrofoam Workspace [Melting]

12/02/2019 at 14:14

Hi everyone! My name is Carolina i’m currently in Eindhoven and the next few months i’ll be working on designing a Styrofoam Workspace for Version 4, in order to make more efficient this process, because, as everybody may know, Styrofoam it’s hardly ever recycled, because of the high costs involved in transportation due to the amount of air it has inside (98%).

Maybe if you ever tried to recycle this material with the Precious Plastic machines, you might have noticed that they are not designed for this kind of waste, so, for example, when I first tried with the shredder, the first thing I realised was that the eps tends to jump a lot while shredding because of its low weight. This also meant that the shredding process was really slow compared to other types of plastics. Also in my experience with the extrusion machine, I obtained good results in terms of the material (image 1), but as well as the shredder, it was really slow, it took me about 50 minutes to extrude the full bucket (6.5 lt o 6462 cm3) at 167 rpm, and usually when you extrude any other plastic, for example PP (Polypropylene) a full bucket can take around 20-25 minutes in the same extruder, and also the big difference between these two, is that, beside the time it took to extrude the material, after this, the material reduces 90% it volumen (Image 2).

After this experience I realized 4 things:

1) There’s no need to use solvents to transform de EPS into PS

2) The material definitely needs a particular technique for recycling it (priority: find ways to grab/shred more material in less time).

3) It needs a vacuum system in order to make the shredding process as clean as possible (static issue)
4) This process needs to be efficient to make it worth it

So the main goal is to make this whole process:

– Cheap

– Efficient

– Clean

– Hopefully with the least amount of steps as possible

First idea of the line production for the Styrofoam Workspace:

1) Storage

2) Shredding

3) Pelletize

As I mentioned before, in a normal extruder the material takes too long to get out of it, this is because of it lightweight (again) so while I was extruding I had to constantly push the material into the extruder, because when you use a extrusion screw, this ones have different diameters all along the screw, so with this, it moves the material towards the nozzle with pressure, the problem with this, in relation with styrofoam, is that in this case, the priority is to grab as much material as possible and with the different diameters that’s not possible, so the easiest way to extrude it faster is to use a drill instead of the extrusion screw or a worm shaft (image 3), and, as you can imagine, the bigger the diameter is, the more material will be able to transform in the same amount of time.
Another thing I was thinking about, its that maybe it could be faster to pelletize the material while it comes out from the extruder, instead of extrude and then shred it. Basically its the same but the two of them integrated in only one machine

4) Inject

The idea of ​​proposing injection as a method of product creation, is that due to all the volume that is reduced at the process of recovering the PS,  low amounts of raw material will be obtained, therefore, to generate a considerable output of products, these must be of a small scale, so the injection machine is perfect for this!

Also I will like to share with you my experience injecting Styrofoam, it was a interesting and surprising result. I made it without releasing the aire before injecting, I put the shredded styrofoam directly on the injection machine, obviously it took much more time than with the other type of plastics, I had to press it like 10 times before injecting (image 4)

So in this topic I invite you to discuss of extrusion/ pelletizing/ Injection etc. (with styrofoam) you know/ have experienced!

To talk about melting Cutting + Shredding processes for Styrofoam got to:

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12/02/2019 at 14:16

Image 4

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