Material Science of 3D Printing Filaments Milwaukee 3D Meet Up Coex3D 11-2-2013
Dec 17, 2015
Topics
• Filament Manufacturing• Upstream• Extrusion• Down Stream
• Polymer Science 101• Monomers• Morphology• Melt Behavior
• Filaments• Discussion
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
•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
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 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
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
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