PLASTIC MATERIAL PROPERTIES & SELECTION PROCESS
INTRODUCTION FOR PLASTIC MATERIAL PROPERTIES & SELECTION PROCESS
Plastic parts range from simple devices to complicated test equipment and implants. Plastics in engineering are used more and more for weight, cost, and performance purposes. This workshop will discuss plastics used in the injection molding process for medical, automotive and audio industries. The first section will review the general composition of plastic materials which will include the materials added to the basic polymers. The second section will discuss many factors that contribute to the plastic selection. The final section will review the chemistry and the application of most common plastic materials.
COURSE OBJECTIVE
- Polymer properties
- Polymer additives & modifiers
- Material selection process
- Common polymers & their physical, thermal & chemical properties
- Plastic injection molding do’s & dont’s
- Common polymer issues faced at your workplace and a systematic way to resolve them
COURSE CONTENT
1) Introduction to polymers (thermoplastic and thermosets)
- Linear, Branched, Cross-linked Polymers
- Isomers
- Molecular Weight
2) Additives
- Fillers
- Impact Modifiers and Tougheners
- Radiation Stabilizers
- Pigments, Extenders, Dyes, Mica
- Thermal Stabilizers & Antistats
- BaSo4
3) Material selection process
i. Physical and Mechanical Properties
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- Fatigue
- Wear resistance
- COF (Coefficient of friction)
- Shrinkage
- Moisture absorption
- Strength
- UV resistance
ii. Flammability
iii. Thermal Properties
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- CUT temperature
- ARO temperature
iv. Electrical Properties
v. Chemical Resistance
vi. Sterilization Capability
vii. Long-Term Durability
viii. Leachables and Extractables
ix. Shelf Life and Aging
x. Joining and Welding
xi. Medical Grade Plastics
xii. Food grade Plastics
4) Common polymers & their physical, thermal & chemical properties
i. The 4 documents that we must have from every polymer raw material supplier
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- Material properties data sheet
- Material processing data sheet
- Material design guidelines
- MSDS
ii. Semi-crystalline resin
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- PP
- PE
- POM
- PBT
- PPS
- PEEK
- PFA, PVDF
- PA
iii. Amorphous resin
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- PS
- PMMA
- PC
- PVC
- ABS
- PPE
- PSU, PES
iv. Polyurethane (PUR)
v. Fluorinated Ethylene-Propylene (FEP).
vi. Methacrylate Acrylonitrile Butadiene Styrene (MABS)
vii. Measurements of the resin
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- melt flow index
- density
- molecular weight distribution
- melting point, softening point
viii. Measurements of the converted articles
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- dimensional stability
- shrinkage
- warpage
- stressed-crack
- surface tackiness
ix. How to measure and quantify shrinkage and warpage?
x. Common injection molding problems and troubleshooting
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