Large molecules with a huge molecular
Made of repeating structural units
Connected by covalent chemical bonds
poly – “many”; -mers – “parts”
Examples: plastics, rubbers and polyester
Thermoplastic polymers or thermoplastics
Thermosetting polymers or thermosets
Is a manufacturing process in which a
polymer is heated to a highly plastic state
and forced to flow under high pressure into
a mold cavity, where it solidifies.
• It has the most precise control of
shape and dimensions.
• Highly automatic process.
• Fast cycle time.
• It has high setup cost.
• Only good for large numbers of parts.
• Large pressures in mold (20,000 psi).