Difference of outer and inner diameters at valve gate result

The Difference of outer and inner diameters at valve gate is a non-default result generated only for valve gates when the Variable speed control option is selected. This result shows the dynamic dimensional change of the polymer flow channel as the valve pin travels inside it.

Note: For models with a 3D mesh, the variable speed valve gate controller must be assigned on beam elements only.

Using this result

The Difference of outer and inner diameters at valve gate result can be used to see how the gap between the valve pin and the gate channel changes in size as the valve gate opens or closes.

Things to look for

When viewing the Difference of outer and inner diameters at valve gate result, watch for the following:

Excessive high shear rates at the valve gate, caused by the gap between the valve pin and the gate channel being too small. Increasing the gap thickness by reducing the valve pin diameter and/or increasing the gate channel diameter will reduce the high shear rates.
Excessive high temperature or flow front temperature downstream of the valve gate, caused by excessive shear heating when polymer melt passing through the valve gate. Increasing the gap thickness and/or increasing the valve gate opening speed will help reduce the temperature rise.
Excessive high flow front velocity downstream of the valve gate, caused by fast opening of the valve gate. Reducing the initial opening speed of the valve gate will help reduce the flow front speed downstream.