MOLDING MATERIALS
Choosing the right plastic material is a critical step in any custom injection molding project. The performance, durability, and appearance of your final part depend heavily on this decision.
Before selecting a material, consider key factors such as:
✎ Part function and application
✎ Required strength, flexibility, and impact resistance
✎ Environmental exposure (e.g., UV, heat, chemicals)
✎ Aesthetic requirements (color, surface finish)
✎ Regulatory or industry standards (e.g., food-grade, medical, flame retardant)
Different plastics exhibit unique behaviors during molding and in end-use conditions. One often-overlooked factor is material shrinkage. Each resin shrinks at a different rate as it cools, which directly affects dimensional accuracy.
Important: If you change materials between production runs—even with the same mold—part dimensions may vary due to differences in shrink rates. This can impact fit, function, and assembly.
To help guide your selection, below is a table of the most commonly used thermoplastics in injection molding, along with their key properties and typical applications.
