Setting valve gates

Polymer valve gates are used to control the filling pattern in the mold cavity with the aim of avoiding defects such as flash, drooling, and weld lines.

Valve gates can be assigned to beam elements having the property type Hot gate for all flow solvers.

When the Gas-assisted Injection Molding process is selected, valve gates can also be assigned to elements having the property type Overflow well, depending on the mesh type:

• Triangular shell elements (Midplane mesh type only)
• Beam elements (Midplane and 3D mesh types
• Tetrahedral elements (3D mesh type only)

Note: A valve gate must not be assigned to the same element as an injection location. You should either model the feed system ahead of the valve gate, or ensure that the gate is meshed with more than one element along its length, and then assign the valve gate to the gate element attached to the part.

1. Zoom in on the location of the model with the hot gate or overflow well where you want to set a valve gate.
2. Click (Select) and then click on the hot gate or overflow well element to select it.
   Note: If the meshed hot gate or overflow well comprises more than one element, you must only set the valve gate on the element directly connected to the part.
3. Right-click on the selected hot gate or overflow well element and select Properties to display the property dialog for that element.
4. Select the Valve Control tab, click Select next to the Valve gate controller drop-down list, click on the default entry Valve gate controller defaults or another controller that you have previously defined, then click Select to return to the element property dialog.
5. Click Edit next to the Valve gate controller drop-down list, select the method by which the timing of the valve gate will be controlled in the Valve gate control by drop-down list, and then click Edit Settings.
6. On the Valve gate timing dialog, enter the required timing parameters for the selected control method:

   Control by time method

   Select whether the valve gate is initially open or closed, then enter the times (sec), from the start of injection, at which further opening/closing of the valve gate is to occur. If you choose initially Open, the first entry in the Valve gate control by time table should be 0s. If you choose initially Closed, the first entry in the Valve gate control by time table should greater than 0s.

   Control by flow front method

   Select whether the triggering location is the gate node or another specified model node. If required, enter a delay time before the valve gate opens, measured from the time the flow front reaches the trigger location, and then enter the times (sec), from the valve gate opening time, at which further opening/closing of the valve gate is to occur.

   Control by pressure method

   Select whether the valve gate is initially open or closed, select whether the triggering location is the gate node or another specified model node, then enter the pressure values at which further opening/closing of the valve gate is to occur.

   Control by %volume method

   Select whether the valve gate is initially open or closed, then enter the %volume filled values at which further opening/closing of the valve gate is to occur.

   Control by ram position method

   Select whether the valve gate is initially open or closed, then enter the ram position values at which further opening/closing of the valve gate is to occur.

7. Click OK to close the Valve gate timing dialog.
8. Enter a new name for the valve gate controller, then click OK to close the Valve gate controller dialog.
   Note: If other gates exist for this model, ensure the Apply to all entities that share this property checkbox is deselected to prevent the valve gate controller from being applied to other elements sharing this gate property, and change the name of the gate property to make it unique.
9. Click OK to close the element property dialog.
10. Repeat the above steps for each gate or overflow well element at which you want to set a valve gate. If the timing method and parameters for a valve gate are identical to that of a previously set valve gate, select the previously defined valve gate controller to assign the same timings.

Tip: Click (Boundary Conditions tab > Feed System panel > Valve Gate Timing) to edit the timing of all assigned valve gates in the model.