Setting a gate contact diameter

A gate contact diameter is used by the Coupled 3D Flow solver in a Fill or Fill+Pack analysis.

To access this dialog, choose an analysis sequence which includes Fill or Fill+Pack. Click Analysis > Process Settings Wizard. Click Next, if necessary, until the Fill or Fill+Pack page appears. Click Advanced Options, then click Edit in the Solver Parameters group. On the Thermoplastics injection molding solver parameters (3D) dialog, select the Fill+Pack Analysis tab. In the Solver setup group, select Use coupled solver, then click Solver Parameters.

The Gate contact diameter option assigns a virtual gate diameter to each injection node when a modeled gate or runner system is not provided (direct injection). This improves the flow front prediction and provides more accurate pressure results and better jetting representation around the gate. However, where possible, it is advisable to include a modeled gate or runner system.

Note: The gate contact diameter has no effect when injecting into a beam element or at a gas injection location. However, polymer injection during a Gas-assisted Injection Molding analysis is affected.

Automatic

Assigns a gate contact diameter based on the facet size around the injection node. The default diameter assigned is based on the molding process, but is checked and potentially adjusted based on the mesh size.

• Thermoplastic-default gate size 2mm
• Thermoset-default gate size 1mm
• Underfill-default gate size 0.1mm

To ensure that the applied gate diameter is reasonable, mesh-dependent upper and lower limits are applied. The effective surface area (A)of the injection node is calculated as one third of the sum of the tetrahedral surface facets surrounding the node. From (A), an effective diameter (D) is calculated. The upper and lower limits are then set as (10D) and (D), respectively.

For example, if the effective diameter (D) is 2mm, then the upper and lower limits are set as 20mm (10D) and 2mm (D), respectively.

• If (default gate size value) < D, then the lower limit D is used.
• If (default gate size value) > 10D, the the upper limit 10D is used.
• Otherwise the default values are used.

As a result of these calculations, if more than one injection location is specified, the individual gate diameters may vary.

Specified

Allows you to enter the actual diameter of the gate(s).

If more that one injection location is specified, all gates will have the same size, temperature, pressure and shrinkage irrespective of the part geometry or facet size.