•    State-of-the Art Molding
        - “Scientific Molding”

• Scientific Molding is a “disciplined, systematic approach to molding based on fundamental understanding of what happens to plastic during injection molding.” Focus is performance of the melt in the mold.
• Focus is NOT set points of machine.
• Scientific molding is a “machine independent” process
   • Key Parameters:
             – Velocity of Injection
                   • Push the same amount of material at the same rate.
             – Plastic Temperature (not barrel temperature)
             – Plastic Pressure (not hydraulic pressure)
             – Cooling
   • Key is Viscosity Control
             – Viscosity changes as flow rate changes
             – If flow rate changes, then viscosity changes
             – If viscosity changes, then parts will vary.

•    The “Relative Viscosity Curve”
     or Melt Rheology
        –Develop Viscosity curve to define optimum           injection velocity
        –Viscosity Curve looks like slanted “L”