Tips to Improve Mechanical Properties

Tensile Strength

  • Use hotter mold temperatures
  • Use high injection speed
  • Avoid high melt temperature
  • Injection pressure has little effect

Tensile Elongation

  • Use hotter mold temperatures
  • Avoid high melt temperature

Flexural Modulus

  • Use higher melt temperatures
  • Use high injection speed
  • Injection pressure has only moderate effect

Flexural Strength

  • Use hotter mold temperatures
  • Avoid high melt temperature
  • Injection pressure has only moderate effect

Notched IZOD Impact

  • Use hotter mold temperatures (cold mold can cause 50% loss in impact strength)
  • Avoid high melt temperature

Shrinkage

  • Use cold mold to reduces shrinkage
  • Use high injection pressure
  • Avoid high screw rpm
  • Avoid high melt temperatures

Warpage

  • Use longer hold time reduces warpage
  • Reduce stress with high mold and melt temperatures

Regrind Usage

Generally, 20% regrind is acceptable. There are times when no regrind is permissible. The application should always be thoroughly tested. Regrind should always be kept clean, dry and uniformly mixed with the virgin material.