Venting analysis

Venting analysis is used to predict the effects of air pressure on the flow of polymer to aid in selecting suitable locations where vents may be placed in the mold to allow trapped air to escape the cavity.

The option to perform a venting analysis is available for 3D Thermoplastics Injection Molding, Thermoplastics Overmolding, Reactive Molding and Microchip Encapsulation molding processes when an analysis sequence that includes Fill or Fill+Pack (using the Coupled 3D Flow solver) is selected.

The venting analysis calculates the pressure drop through specified venting analysis locations (air vents), based on analytical equations that account for compressible polymer flow behavior.

The venting analysis also calculates the pressure within air traps remaining in the part, using ideal gas law equations.

These calculated air trap pressures are then applied as boundary conditions defining the pressure at the melt front when solving the flow equations. These calculations show the effect of air pressure within the cavity on the flow of polymer.

You must specify at least one venting analysis location (node on the 3D model) before starting the analysis. You can accept the default values for vent properties, or you can specify values for these properties, including vent size, vent exit pressure, minimum void volume, and venting analysis locations grouping.

Results specific to venting analysis include the Air traps, including air vents result and the Vent region pressure result.