MEGR 3232 – Plastics Design – Exam 2 Review Notes

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MEGR 3232

Plastics Design –
Exam 2 Review Notes
Injection Molding • Extrusion •
Thermoforming • Blow Molding

( 2025–2026 Study Year )

,Table of Contents
MEGR 3232 Exam 2 Review Notes (2025–2026 Study Year)
__________________________________________________________
[ 1 ] Primary Polymer Processes

● Extrusion
● Thermoforming
● Blow molding
● Rotational molding
● Compression molding
● Injection molding
● Other processes (melt spinning, filament winding, resin transfer
molding)

[ 2 ] Extrusion

● What extrusion makes
● Extrusion dies
● Advantages & disadvantages
● Types: profile, sheet/film, blown film
● Compounding

[ 3 ] Thermoforming

● Process overview
● Examples
● Advantages & disadvantages
● Material limitations

[ 4 ] Blow Molding

● Process overview
● Examples
● Stretch blow molding
● Advantages & disadvantages
● Material limitations

, [ 5 ] Rotational Molding

● Process overview
● Examples
● Advantages & disadvantages
● Material limitations

[ 6 ] Compression Molding

● Process overview
● Historical context
● Examples
● Advantages & disadvantages

[ 7 ] Injection Molding Overview

● Why injection molding is the most important process
● High pressure → high detail
● Advantages & disadvantages
● Summary table of all processes

[ 8 ] Injection Molding Machine Components

● Clamping unit
● Injection unit
● How pellets arrive & move
● Dryers, hopper loaders, mixing additives

[ 9 ] Screw Design & Zones

● Feed zone
● Transition zone
● Metering zone
● Screw sizing terms
● Special screw designs (Nylon vs. PVC/ABS/PC)

[ 10 ] Shot Size

● 40–60% rule
● Problems with too small or too large shots

[ 11 ] Pressure Intensification

● Plastic pressure vs hydraulic pressure
● Check valves (ring vs ball)