Video summary

3D Filament From PET Bottle + Controller PCB

Main summary

Key takeaways

Technology

Technology / Project Overview

  • The video documents building a “bottle-to-filament” machine that converts PET bottles into 3D-printable filament (targeting ~1.75 mm diameter).
  • The maker builds:
    • A custom filament puller (gears + stepper motor + bearings)
    • A heated extrusion block (12V heater + thermistor) to melt and pull the PET strip into filament
  • A custom PCB controlled by Arduino manages:
    • Heater temperature control via MOSFET switching and feedback from a thermistor
    • Stepper motor speed control via a stepper driver output
    • An optional fan output and planned UI peripherals (display, encoder, etc.)

Hardware / Mechanical Build Details (Key Features)

Filament Puller

  • Uses 3D-printed parts (PLA), including:
    • Two large gears with a cylinder spacing piece
  • Torque is improved with:
    • An additional small gear coupled to a stepper motor via another small gear
  • Bearings:
    • 608 ZZ bearings, placed on both sides for gear support
  • Mounting:
    • Everything is assembled on a wood board using screws, bearings, and an M8 threaded rod

Spool / Guide

  • Includes a spool holder and a guide/straightener to keep the PET strip feeding horizontally toward the hot block.

Heating Block

  • Uses a stock aluminum heater block from a 3D printer, containing:
    • A 12V heater
    • A thermistor
  • Nozzle / hole modification:
    • Drill enlargement steps:
      • Removes thread
      • Then enlarges and shapes the inlet
    • Adds a brass nozzle, referencing drills around 1.8 mm
  • Heat safety / material choice:
    • PET melt point is above 200°C, so the block should use metal parts

PCB / Electronics & Control System (Major Concepts)

  • The creator provides a custom PCB with space/connectors for:
    • Arduino
    • Stepper driver
    • Thermistor input and voltage divider support
    • Heater output via MOSFETs (mentions two MOSFET slots)
    • Fan output (optional)
    • UI components: LCD screen and rotary encoder
    • Screw terminals for inputs/outputs
  • Power:
    • Requires 12V power for the PCB/system
  • PCB ordering + files:
    • The video promotes downloading Gerber files and ordering through pcbway.com
    • Claims quick, low-cost boards (stated: ~$5 for testing/prototyping)

Firmware / Software Verification (Tutorial / Test Sequence)

The build is tested in stages using Arduino code:

  1. Thermistor temperature readout
    • Upload code to read the thermistor and display the value on the LCD.
  2. Stepper motor test
    • Uploads code in an “AccelStepper” style (subtitle references an “excel stepper library”).
    • Motor speed changes via a potentiometer.
    • Rotation is enabled with a push button.
  3. Heater temperature closed-loop control
    • Uses a PD controller (subtitle says “pid control” but behavior described is PD-like).
    • Regulates heater power with PWM through the MOSFET.
    • Target/setpoint: 200°C
    • Stability demonstration:
      • PWM output reduces as it approaches setpoint
      • Temperature then holds around 200°C
  4. Integrated final system
    • Combined code controls:
      • heater temperature
      • stepper speed
      • LCD updates (displaying output values)
    • Speed remains adjustable via the potentiometer

PET Strip Preparation & Filament Making Process (Practical Guide)

Smoothing the Bottle

  • To remove bottle contours/ridges:
    • Fill the bottle with water, boil to increase internal pressure and soften/vaporize surfaces
    • Alternative: use a heat gun to soften

Cutting Strips

  • Uses a 3D-printed strip cutter (bearing-assisted cutter mentioned; alignment wasn’t perfect).
  • Process:
    • Cut the bottom of the bottle
    • Insert into the cutter
    • Pull to create long strips

Feeding and Extrusion

  • Strip is wound onto a spool holder.
  • Strip tip is trimmed and inserted into the extruder.
  • It is pulled until it reaches the puller/spool.
  • Machine parameters require tuning:
    • Adjust pull speed, tape width, and/or nozzle diameter to achieve ~1.75 mm filament
    • Notes: more inflated bottles typically produce thinner filament later

3D Printing Test Results (Outcome / Observations)

  • The homemade PET filament is tested on an existing 3D printer:
    • Preheats to 260°C
    • Prints a cube test model
  • Observations:
    • The printer initially struggled to hold 260°C, causing imperfect early layers
    • Later adjustments:
      • decrease speed
      • increase flow rate
    • Filament briefly stuck, then printing resumed
  • Conclusion:
    • The filament is printable, but requires further tuning (temperature/speed/flow) for consistent quality

Key “Review / Guide / Tutorial” Takeaways

  • A step-by-step build combining:
    • mechanical puller
    • heated block
    • PCB/Arduino control
    • final filament production process
  • Emphasis areas:
    • Closed-loop temperature control using thermistor feedback + MOSFET PWM
    • Iterative tuning to reach ~1.75 mm diameter
    • Bottle pre-treatment via boiling to smooth the surface
  • Provides downloadable assets/promotional resources:
    • PCB via pcbway (Gerbers + ordering steps)
    • Mentions downloading schematic/code (also references electronics.com / electrons.com in subtitles)

Main Speakers / Sources

  • Main speaker/creator: the YouTube uploader (uses “I / my”; directs viewers to download PCB/files and mentions Patreon/shop).
  • Sources / tools referenced:
    • Arduino
    • An AccelStepper-like stepper control library
    • pcbway.com (PCB ordering)
    • Electronics.com / electrons.com (where schematic/code/assets are claimed to be available)

Original video