Material Science of 3D Printing Filaments

Milwaukee 3D Meet Up

Coex3D

11-2-2013 

Topics

• Filament Manufacturing• Upstream• Extrusion• Down Stream

• Polymer Science 101• Monomers• Morphology• Melt Behavior

• Filaments• Discussion

Filament Manufacturing

Resin Drying• Critical steps in resin processing• Hydrophilic resins needs to be dried to make 3D filament• PLA, PET, PC, PA, PVOH are highly Hydrophilic• ABS slightly Hydrophilic 

Filament ManufacturingUp-Stream Processing

Resin Drying

Filament ManufacturingUp-Stream Processing

•Color Feeders • Color concentrates• Additives

• Throat Mixers

•Magnet

Filament ManufacturingUp-Stream Processing

Filament ManufacturingReal Extruders

Extruder Elements• Zone Heated Barrel• Screw• Screen Pack• Breaker Plate

Filament ManufacturingReal Extruders

Process Conditions on Extruders• Melt Temperature• Melt Pressure • RPMs• Motor Load

Filament ManufacturingReal Extruders

Extruder Screws• Feeding•Melting• Compression•Mixing•Material Specific

Filament ManufacturingWater Quench

Water Bath• Filaments are often water quenched• Molten phase to solid phase• Methods are often trade secret• 10-30 feet water cooling 

Filament ManufacturingFilament Orientation

Filament ManufacturingLaser Micrometer

Filament ManufacturingSpooling

Filament ManufacturingPackaging

Polymer Science for 3D Printers

Polymer Science 101 for 3D PrintersPlastic vs. Polymer

Plastic•  Plastics are polymers which, under appropriate conditions of temperature and pressure, can be molded or shaped.

Polymer• A large molecule formed by the chemical union of five or more identical combining units called monomers

Polymers Science 101Monomers

• Number of monomers (Molecular Weight)  influences viscosity and strength properties  • (wax 30-350 RU, PP 7,000 – 24,000 RU)

• Types and location of the monomer influence polymer chemical and mechanical properties

Polymers Science 101Morphology

Polymers Science 101Melt Behavior - Viscosity

• Viscosity• Melt Index Test (MI or MFR)

• Mass/Time @ Temp & Weight• 3D Printing Filaments are

typically injection molding resin grades• 10+g/10 min @ 220°C 10kg

• Lower MI or MFR would require more force on filament advance

• Intrinsic viscosity (IV) is used to measure viscosity for polymers like PET

Polymers Science 101Melt Behavior – Melting Temps

• Thermal Transitions• Glass Transition – Amorphous materials flow, they do not melt• Melting Point – The temp at which a crystalline structure transitions to a liquid Amorphous structure 

3D Printing Filaments

Polymer Science 101Polylactide (PLA) - General

Polylactide (PLA)• Biopolymer - derived from corn• Relatively clean resin• Condensation reaction• Translucent• Translucent Blue

Polymer Science 101Polylactide

Polylactide (PLA)• Morphology

• Semi-crystalline polymers• Filament production method and colorants will change crystalinity levels• Resin has a Tg 55-60°C & Tm of 145-160°C• Different processing temps on printer (≈220°C)

• Melt Behavior • MFR: 6 g/10 min (210°C & 2.16 Kg)

• Monomer• Latic Acid

• Density: 1.24 g/cc

Polymer Science 101ABS

Acrylonitrile Butadiene Styrene• Derived from 3 monomers•Monomers % - Properties• Not a clean resin to extrude• Opaque

Polymer Science 101ABS

Acrylonitrile Butadiene Styrene (ABS)• Morphology

• Amorphous• Grade dependent Tg 100°C - 130°C

• Melt Behavior • MFR: 1.1 g/10 min (200° C & 5 Kg)• MFR: 13 g/10 min (220° C & 10 Kg)

• Monomer• Acrylonitrile, Styrene & Butadiene

• Density: 1.03 g/cc

Polymer Science 101PVOH

PVOH• Water soluble polymer• Commonly used in 3D Printing

for structural elements that are dissolved after print is complete• Narrow gap between PVOH

melting temp and thermal degradation – run as cool as possible • Keep Dry when not in use

Polymer Science 101CX-Glass & CoPET

• CX-Glass (Developmental) • Glass like polymer• Extremely clean polymer• Morphology

• Amorphous

• Melt Behavior • MFR: 13 g/10 min (220° C & 10 Kg)

• Clear

• Heated bed required

CoPET (Developmental) • Copolyester polymer• Clean polymer• Morphology

• Amorphous

• Melt Behavior • MFR: 10 g/10 min (220° C & 10 Kg)

• Clear

Typical Printing Range

Comments

Polymer Morphology Monomer Density190C @ 21.6 Kg

210C @ 2.16 Kg

220 C @ 10 Kg

230 C @ 2.16 Kg

Tglass VSP Tmelting

(g/cc) (°C) (°C) (°C) (°C)ABS Amorphous  15-30% AN, 5-30%B 40-60% S 1.03 13 217 210-240 Slightly Hydrophillic

ABS - HT  Amorphous  15-30% AN, 5-30%B 40-60% S 1.06 6 257 250-265 Slightly Hydrophillic

PLA Semi-Crystalline Lactic Acid 1.24 6 145-160 210-230 Higly Hydrophillic

PVOH Amorphous Vinyl Alcohol 1.28 27 85 120 160-180Higly Hydrophillic, Run 

Cool 

CoPET Amorphous  NA 1.27 10 80 85 240-265 Higly HydrophillicCX-Glass Amorphous  NA 1.02 11 78 220-240 NA

General Polymer Properties General Filament Properties

(g/10 min)

MFR

Polymer Science 101CX-Glass & CoPET

Thank You

If you would like a copy of the presentation just drop me an email at

Sales@CoexLLC.com

Or

coex3d.com/contact