I wanted to build something useful for Fablab Puebla, so I decided to build a plastic shredder inspired on the "precious plastics" project.  And based on it I made my own this has been a very interesting experience on which I used  many skills developed during the fabacademy.

You can download the files HERE

To start the project the first step was to determine the materials needed to build it and make an inventory of which of the where available in Fablab Puebla.

The main element of the system are the shredding blades which are made of stainless steel, used some blueprints downloaded from the internet to machine them, however as I didn't find all the necessary materials I had to make some changes to those blueprints to adapt the pieces to the new material measures.


To build this machine I used 3D and 2D modeling, water jet cutting, laser cutting, welding, programming,  just to mention some the processes. The main part of this machine (the schredder) is made out of stainless steel, it is fun working with metals however sometimes gets hard.


To be sure those changes where right I iterate on the proces cutting the pieces on MDF to be sure they will fit.

Once I was sure the new measures where right I started cutting the stainless steel pieces using a water jet machine, this process took me several hours because of the stainless steel hardness and the quantity of pieces.


link to: Bill of materials

With the pieces ready the assembly process started, some extra machining was needed for example lathing the axis, putting all together the right way was very important the pieces have assembly  direction and order.

With the blades partially assembled the first trials were done to be sure it will work.

With the blades partially assembled the first trials were done to be sure it will work. After having the schredder assembled I built the base on which I placed the motor, the gear motor and the shredder, once everything was working well I designed the hopper, the motor cover and the container.

For the electronics part I built a digital scale using a load cell, an ATtiny 84, a HX711 amplifier  and a bluetooth HC05 module. I designed the board using Eagle and a Modela machine to make it.

I also designed an app to receive data with my smartphone this app was developed using MITapp Inventor 2.

My scale was working perfectly until I changed the bluetooth module to solder it, I'm not sure what happened, i`m quiet mad about this because I wasn`t able to make a video with the scale working well. (I guess it has something to be with the "murphy laws" lol.)