Cross-linking a high-level 101 of the injection molding manufacturing process: Basics of Injection Molding
Thermoplastics and thermoset plastics are commonly used in injection molding, and each of the two have their own unique advantages.
What’s the Difference?
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Thermoset Plastics: Linked by covalent bonds; undergo curing process during heating and shaping which causes permanent chemical change in molecular structure. Common materials include epoxy, silicone, polyurethane.
(TLDR; material remains in a permanent solid state after being cured once).
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Thermoplastics: Linked by Van der Waals bonds; can be heated and reheated, reversible plastic operation
Advantages/Disadvantages:
Thermoplastics
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Advantages
- Commonly used for aesthetic surface finishes
- Recylability, end plastic part can be re-melted and formed into different shapes (commonly ued for toys, furniture, etc.)
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Disadvantages
- Ineffective for parts regularly exposed to extreme heat or rapidly varying temperature ranges as they can melt more easily
- Molding process requires higher heat and pressure to create parts
Thermoset Plastics
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Advantages
- Generally do not melt when exposed to heat
- Do not deform, warp, or lose shape in varying temp. ranges
- Molding process is cheaper as they require less complex tooling (i.e. far less heat and pressure)
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Disadvantages
- Much more difficult to surface finish
- Cannot be remolded or reshaped
- Poor thermal conductivity and rigidity