Filament Extruder for 3D Printer

Khaled Abdel-Rahim, Mitchell Flynn, RJ Munn, & Kirk Riedner

Introduction

• In 2013, the Chemicals and Materials Science Engineering Department purchased a 3D printer.

• MakerBot Replicator 2X

• Purpose of the 3D printer is to fabricate parts for projects and research

• Reduce cost• Use polymers as a substitute for metal parts

• Disadvantage is the price of 1 kg spool of filament• Buying pellets in bulk can reduce the cost from $43 to $21 per kilogram

Design Objectives & Constraints

• Extruder • Take polymer pellets and shavings• Form them into a filament strand with a diameter of 1.75 mm ± 0.10 mm

• Tension Rollers• Keep tension when filament is being wound• Maintain constant filament diameter

• Take-Up Spool• Wind the filament strand on the a 1 lb. or 1 kg spool

Design Objectives & Constraints

• Shredder• Recycle previous or failed prints and printing byproducts into shavings for

extruder• Shred polymers such as

• HDPE (milk jugs)• Polypropylene (baler twine)

Input/Output Diagram

Nozzle with Pre-Set Diameter

Polymer Pellets (ABS & PLA)

Hopper

Failed or Unwanted 3D Printer Products (ABS, PLA, HDPE, etc.) Shredder

Heated Barrel

Cooling Fan

Tension Rollers & Take-Up Spool

1 lb. or 1 kg Spool of 1.75 mm filament

Design Results

• Extruder• Variable Frequency Motor & Gear Reduction Box

Design Results

• Extruder• Variable Frequency Motor & Gear Reduction Box• Custom Mounting Block & Motor Coupling

Design Results

• Extruder• Variable Frequency Motor & Gear Reduction Box• Custom Mounting Block and Motor Coupling• 5/8 inch Auger bit by 17 inches

Design Results

• Extruder• Variable Frequency Motor & Gear Reduction• Custom Mounting Block and Motor Coupling• 5/8 inch Auger bit by 17 inches• Printed Hopper

Design Results

• Extruder• Variable Frequency Motor & Gear Reduction Box• Custom Mounting Block and Motor Coupling• 5/8 inch Auger bit by 17 inches• Printed Hopper• Barrel made of Stainless Steel and Brass Nozzle

Design Results

• Extruder• Variable Frequency Motor & Gear Reduction Box• Custom Mounting Block and Motor Coupling• 5/8 inch Auger bit by 17 inches• Printed Hopper• Barrel made of Stainless Steel and Brass Nozzle• 1 inch band heater with controller

• Temperature set point is 300 °C for ABS

Design Results

• Extruder• Variable Frequency Motor & Gear Reduction Box• Custom Mounting Block and Motor Coupling• 5/8 inch Auger bit by 17 inches• Printed Hopper• Barrel made of Stainless Steel and Brass Nozzle• 1 inch band heater with controller• Temperature set point is 300 °C for ABS

Design Results

• Extruder• Variable Frequency Motor & Gear Reduction Box• Custom Mounting Block and Motor Coupling• 5/8 inch Auger bit by 17 inches• Printed Hopper• Barrel made of Stainless Steel and Brass Nozzle• 1 inch band heater with controller

• Temperature set point is 300 °C for ABS

• Prototype • Extrudes at a maximum rate 14 inches/minute

Design Results

• Tension Rollers • 2 inch long by ½ inch diameter

Design Results

• Tension Rollers • 2 inch long by ½ inch diameter• 1.75 mm Wide Grooves

Design Results

• Tension Rollers • 2 inch long by ½ inch diameter• 1.75 mm Wide Grooves • Timing Belt Pulley• Gear Motor• Printed Gears

Design Results

• Tension Rollers • 2 inch long by ½ inch diameter• 1.75 mm Wide Grooves • Timing Belt Pulley• Gear Motor• Printed Gears

Design Results

• Tension Rollers • 2 inch long by ½ inch diameter• 1.75 mm Wide Grooves • Timing Belt Pulley• Gear Motor• Printed Gears

Design Results

• Take-up Spool• Gear Motor• Printed Inserts and Gear

Design Results

• Take-up Spool• Gear Motor• Printed Inserts and Gear

Design Results

• Shredder• ¾ inch Roughing End Mill

Design Results

• Shredder• ¾ inch Roughing End Mill

• Interchangeable

Design Results

• Shredder• ¾ inch Roughing End Mill

• Interchangeable• Pulley Driven

• Uses the extruder’s motor

Design Results

• Shredder• ¾ inch Roughing End Mill

• Interchangeable• Pulley Driven

• Uses the extruder’s motor

Economic Analysis

• MakerBot spool of natural ABS filament is $43

• Assuming the department uses 16 spools of filament per year, costs come to $688 per year in just filament.

• An extruder can reduce this cost by purchasing ABS pellets at a much lower cost as well as being capable of recycling failed/un-useable printed products with the use of a shredder.

Economic Analysis

• Cost to build the prototype: $460• Cost to build the design: $2,100

• 4 economic scenarios:• (1) Full design- no recycling• (2) Full design- including recycling• (3) Prototype- no recycling• (4) Prototype- including recycling

Economic Analysis

Scenario Total Product Cost

Operating Cost

Total Cost Savings Savings from

RecyclingTotal

SavingsPayout Period

(Years)1: Design $304 $32 $336 $352 $0 $352 5.782: Design (R) $190 $32 $222 $220 $258 $478 4.263: Prototype $304 $32 $336 $352 $0 $352 1.314: Prototype (R) $190 $32 $222 $220 $258 $478 0.96

Economic Analysis

Summary

• Extruder, Tension Rollers, & Take-Up Spool• Take polymer pellets and shavings to form a filament strand • Maintain a desired filament diameter of 1.75 mm ± 0.10 mm

• Approximately 1.80 mm diameter• Extrudes at a rate of 14 inches/min

• Shredder• Recycles faulty or undesired printer projects, printing by products, and other polymers

into shavings• Economic Analysis

• By recycling, it’s estimated that nearly 38% of filament from projects can be reused• By purchasing pellets in bulk, the department saves $30 per kg rather than buying by

the spool

Questions?