I received this question via email last week…
I am new to plastics technology and am looking for input on how to do an in-mold rheology test.
Although there is much training centered around the in-mold rheology curve, the basics are as follows:
- Fill the mold as fast as you can with a short shot during 1st stage velocity controlled injection
- Record the fill time and injection pressure at transfer
- Repeat this process using incrementally slower speeds
- Use 1/(fill time) for apparent Shear Rate
- Use (Pressure)*(Fill Time) for Relative Viscosity
- Graph Relative Viscosity (X axis) vs. Shear Rate (Y axis)
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