Precured Gel - Pads and Parts

Connector Shape

The connector sealant pads are applied from pre-cut stamped part or from slit rolls that are stamped and placed into connectors.  The shape of the connector being sealed determines the shape of the pad. The corners are of particular interest to make processing easier. Rounded corners create edge scrap during stamping, but make it much easier to place the pads into the connectors. Rounded corners increase the cost per part by 5 - 100% depending on the part geometry. So, parts with square corners should be evaluated as first option to determine if the combination of equipment and connector design will prove to be successful.

Side Walls/Seal Cavity Depth

The gel grommet seal must be contained and put under pressure to create a seal.  A recessed seal cavity is required at the rear of the connector to hold the gel seal.  The seal cavity must fully contain the sides of the gel seal, as this is the primary sealing interface.  To minimize assembly issues, the depth of the this cavity should exceed the height of the gel grommet by 0.5 mm to 1.0 mm.  

Support Structure

The support structure is the combination of the above parameters. It is shown in the typical Connector rear view. The total solid gel support should be >50% of the total connector area.

Compression Cap Requirements

The compression cap must be designed to withstand the forces that will be generated when the gel seal is compressed.  It should have a support structure similar to the connector body.  A 45 degree chamfer on the compression cap is recommended for better distribution of stresses.

When compressed, the cap should provide 1 kg/cm2 of initial pressure.  It should be noted that this pressure will quickly relax (within about an hour) to 60% of this initial value and then should remain stable.

In connector applications where exposure to high pressure water spray or steam spray is required, the mechanical design of the compression cap should include features to break up or otherwise prevent spray from directly impinging upon the gel seal.

Primary and Secondary Locking

Symmetrical latches, for the compression cap, are recommended along the longer side of the connector recess.  Many connectors, especially those used in automotive underhood applications, use both primary and secondary locking.  Primary locking is either designed onto the contact or into the connector body.  Secondary locking is an additional part that secures the primary locking mechanism to insure that a contact cannot push back.