Venting

Welding GORE® Membrane Discs

AVS 32 Group 7883, AVS 28

GORE® Automotive Vents are available as die-cut disks bulk packaged in a bag or individually presented on a spool in various diameters.

Two processes are approved for joining vents with a plastic component:
Ultrasonic welding or thermal contact welding.


 

Ultrasonic Welding

The ultrasonic welding technique works via mechanical vibrations with a frequency of approximately 35 kHz, which is beyond the upper human audibility limit. The sonotrode of the welding system consists of a titanium alloy. The component’s thermoplastic material melts on the contact surface and joins with the venting membrane, which remains intact.

This technique results in a strong mechanical connection of both materials.

 

Thermal Contact Welding

The thermal contact welding technique operates with a continuously heated welding tool made of brass. The welding tool’s temperature ranges from approximately 50°C to 100°C above the melting point of the component’s thermoplastic material.

The welding system affects the membrane at a defined pressure over a defined period. The component’s plastic directly beneath the venting membrane melts and joins the vent to the component.

Again, the membrane remains intact. This technique results in a strong mechanical joint.

Preparation

The following points need to be considered prior to welding:

  • The plastic surface to be welded must be even and free from contaminants.
  • It is not recommended to use energy directors for welding membranes.
  • The welding tool should not have any sharp edges and must contact the plastic housing at a 90° angle during welding.
  • The weld stamp surface should be even without any form of texture or topology.
  • Hygroscopic plastics, such as PA, should have a moisture content that is as low as possible.
  • The diameter of the GORE® Automotive Vent should be larger than the outer diameter of the weld stamp.
  • The membrane should be welded from the inside of the housing, depending on the IP protection requirements.
  • To simplify positioning the vent, a target ring is recommended.
  • For ultrasonic welding, the wall thickness below the weld surface should be even and without a pitch or fin.

For optimal installation, a Gore specialist should be consulted early in the design phase to identify the ideal position and design of the vent. Please contact us.