Small-scale shredder


I want to share my shredder called Simbiont. I hope we can all improve it and take inspiring ideas form it 🙂

Plastic waste’s granulator – suitable for use in fablabs, both in terms of the space it needs and its applications. It encourages the contribution of the community to fine grind of HDPE and PP in order to reduce energy consumption. It also makes the recycling process more efficient and transparent.

Thanks!! You can find more details of the project in the images below.

Looks nice!


Have you built a full working model yet? Do you plan to produce these for sale?


Being hand cranked is an attractive feature. I like the planetary gearing, that’s clever, how much mechanical advantage does it give / how much force needs to be applied to the handle?


What size plastic pieces can you put into it, will it take whole bottles? Or just smaller pieces like caps?


Thanks for your interest 🙂

I haven’t built any full working model yet due to the price and the time. I didn’t think about sell it because I haven’t test the entire machine phisically, but I can share the blueprints. The first step was to deliver the project to finish university and now as I have more time I will consider other goals with the work made.

The distinguishing points are based in the usability. The person feeds the machine with pieces of PP or HDPE, could be cups but not big objects, and then the user just need to roll the handle until the perforated drum is empty (in the render the drum isn’t perforated because keyshot got colapsed with the amount of holes). The maximum strenght required of the user while rolling the handle is 11Kg. The relation of the planetary gearing is 8/3, this means that when the handle will have spin 8 times the principal axis will have turned 3 times. So, the axis will rotate slowly to apport more strenght in the tooth blades.

Some important decisions I made about the construction were: using only one rotor (most of the granulators works like this and it needs less pieces), bigger diameter blades to increase the velocity while cutting but taking into account the loss of strenght, multiple tooth to granulate more pieces of plastic per cycle and finally the shape of the tooth.

I hope solved your doubts and generated new ones 😉

very nice! indeed, we would love to have more details 🙂