Part 3: Make Filament Extruder for $465
Let’s agree that not everyone has enough space to keep 5kg per hour extruder as seen in this video — https://youtu.be/Xirli3qDJlU
In this post, we’ll discuss a much cheaper build with much smaller form factor, you might need to read the previous posts to build a good understanding of how this is going to work:
Output: 2kg per hour
Motor
Model: MY1016Z 250W 337rpm Geared DC motor
As this motor is used in ebike conversion kits for bicycles, it’s mass-produced in china which has lowered its price significantly.
You can buy it with motor controller and throttle.
Cost: $50 (Brand new with controller and speed throttle)
Gear Reduction
This motor with 300RPM is still too fast, we need 50RPM from this motor. 300/50=6, so we need a reduction ratio of 6:1 to achieve the desired max speed.
As the motor comes with 11 tooth sprocket, we can simply achieve this by using a 66 tooth sprocket on the extrusion screw.
As the motor can only deliver its maximum power at full speed, this step is very important.
Important: The bigger sprocket fits on the extrusion screw and chain connects the sprocket of motor and sprocket of extrusion screw transmitting torque.
Cost: $10
Screw + Barrel + Nozzle
The screw+barrel+nozzle is available here for cheap: https://store.filamentmachine.com/?product=25mm-screw-and-barrel-set
Barrel, screw and matching nozzle is difficult to find, so I’ve linked it here.
Cost: $370–400
Heater
You can buy resistant wire and coil it around the Barrel in 2 stages.
We need each heater of 300W. To make a resistive heater, all we need to do is figure out the resistance we require. Here we’ll be taking 10A from the socket, most UK sockets can offer 13A, so 10A is a safe value. Since we’ll be using 2 heaters, one heater will receive 5A of current.
R = P / I² = 300W/(5A)² = 12ohm
Our barrel diameter is 25mm which gives us the circumference of 78.53mm
We can use 50 turns of resistance wire per heater stage. The total length of wire required for 50 turns = circumference of barrel * 50 = 78.53*50mm = 39.26cm= 0.392m
We just need to resistance per unit length of wire = r = R/L = 12/0.392m = 30.61ohm/m
Now, all you need to do is look for 30ohm resistance wire on Aliexpress or eBay and buy 1 meter of that wire.
Cost: $5
Thermocouple/SSR/PID controller
You can get a set of this at around $20 per set shipped to you from aliexpress or eBay, there is no way to cut cost on this. The DIY solution will cost more.
Cost: $40 for 2 set
Total: $465
The only reason we can make this for less than $500 is because we are using mass-produced components that are locally available and its production includes a high level of automation.
I hope this will help people who previously got discouraged by expense required to make your own filament.
