The Lab · Rheology

Viscosity Curve

Enter your velocity and pressure readings across the fill range. The tool plots relative viscosity, finds the shear-thinning plateau, and recommends an injection velocity.

Measured points
Material
Melt °C
Mold °C
VelocityPressureFill timeopt
Enter at least two velocity / pressure points to plot the curve.

How to run this study

Find the optimal injection velocity by characterizing how the material’s viscosity responds across a range of fill speeds. This sets the velocity setpoint for every study that follows and identifies the shear-thinning plateau where viscosity is low and the process is robust.

Procedure

  1. 01Set all parameters to recommended starting conditions (barrel temps, clamp, cooling). Disable pack/hold — first stage only.
  2. 02Start at a low injection velocity (e.g. 0.5 in/s) and mold 5 shots to stabilize.
  3. 03Record peak injection pressure and fill time for the stabilized shot.
  4. 04Increase velocity by a fixed increment (e.g. 0.5 in/s), stabilize 5 shots, and record again.
  5. 05Continue through 8–12 setpoints until you hit machine pressure limits or see flash.
  6. 06Enter each velocity/pressure pair — the tool plots relative viscosity (pressure × fill time) and finds the plateau.
  7. 07Take the optimal velocity from the middle of the plateau, where viscosity is lowest and most stable.