Forensic Report: DIY Extruder

Examination

https://poly.cam/capture/B250FA2D-106C-4116-BDEE-7EB37A53F30C

Forensic Questions

What does it do?
An extruder is a machine used to shape materials by pushing them through a die to form long, continuous objects like filaments, tubes, or sheets. In our case it’s made to recycle plastic.
The process involves placing plastic material into a chamber, heating or softening it, and then using a rotating screw to force it through a shaped opening. The nozzle defines the shape of the final output. This particular extruder was created to make recycled plastic filaments.

How does it work?
The extruder works by warming up and melting plastic pellets that are fed by hand via a funnel. There is a motor that moves the pellets through a heating channel and at the same time compresses the melted plastic into a part that forms it and forces it out of the heating channel in the form of plastic filament.

How it's built?
The machine is built under a relatively DIY approach. It has some parts that are from standard machinery such as the nozzle and the agitator wand/drill but it also combines parts that were uniquely created for the final purpose of the machine; there were even some parts that were improvised due to the lack of a more adequate part to serve the purpose. This combination of parts that are both serial manufactured, 3D printed, and improvised give the machine a very experimental aesthetic yet fully functional. It was a case of function over form.

Why it failed, or it wasn't used anymore?
The plastic extruder was still functional, but had some flaws on the outcome of the plastic filament. It needed an extra component to control the actual diameter of the filament and adjust the temperature of the heaters and speed of the motor accordingly.

Steps taken

1. Clean the extruder
2. Documenting it while it was still built
3. Disassembled the differents parts
4. Remove the isolation part with cutter being carefull at the sensors
5. Remove the grinding screw from the pipe, where hardened plastic is stuck, preventing us from taking it out. With heating the pipe
6. Organize and sort all the screws from the different parts.

Testing

After the disassembly process, we meticulously examined each individual component.

We first tested the heaters to melt the plastic stuck in the screw inside the extruder so we could remove the remaining extruder parts. We got the heaters to work so these components are useful.

Finally, we tried to get the only motor in this component to work; it’s a stepper motor. It was a difficult and frustrating task, because it took us a long time. We tried different motor drivers, steppers motors, connections and Arduino codes until we finally make it.

Fist we needed to calibrate the voltage using the potentiometer embedded in the driver. We followed this diagram.

Then we follow the following diagram for the DRV8825 driver, knowing all its pinouts to integrate it into our Arduino. We used a code that rotated the motor in one direction and then in another at different speeds.

Results

How many motors did we find inside?
1 motor, using to turn the big screw.

Does it contain a computer or microcontroller?
No.

Did you found any sensors?
Yes, temperature sensors.

Conclusions

What did you learn?

• How an extruder is assembled
• How an extruder works

What surprised you?

• The fact that we can make the extruder work with not a lot of components
• How easy and repareable it is
• How it is easy to create your own extruder of recycled plastic

Images