Shear rate result (3D)

Using this result

The shear rate is a measure of how quickly the layers of plastic are sliding past each other. If this happens too fast, the polymer chains break and the material degrades.

When the Shear rate (3D) result is displayed, scale the result using Results tab Properties panel Plot Properties and select the Scaling tab to show very high shear rates. The shear rate should be less than the maximum recommended for the material.

The shear rate result may have only small portions of the cross–section that are above the maximum material limit. Regions above the limit could be subject to material degradation, embrittlement and poor surface finish.

When the maximum shear rate is near or above the shear rate limit, it is useful to look at the shear rate as an XY graph.

Things to look for

• High shear rates tend to occur in the feed system (where the greatest velocities are).
• To reduce the shear rate, increase the cross–section or decrease the flow rate