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Ultrasonic Welding Film to Increase Composite Bond Strength

10 February 2010

Scientists at Sensor Products believe that Ultrasonic Welding (USW), is to become more popular within the industry to bond carbon fibre and other composite materials.

This method can be prone to interfacial stresses, which Sensor Products say can be avoided using Pressurex, their patented technology previously used to measure the amount of pressure exerted on honeycomb cores and composite lay-ups.

Pressurex allows the weld operator to set uniform pressure across the material, which should result in welds of greater bond strength and aids in reducing rejected product and lowering base factory cost.

When placed between the horn and the anvil of the ultrasonic bonder, the film instantaneously and permanently changes colour directly proportional to the actual pressure applied. The precise pressure magnitude (PSI or kg/cm2) is then determined by comparing colour variation results to a colour correlation chart (conceptually similar to interpreting Litmus paper). This allows the operator to adjust the equipment, ensuring that pressure is spread evenly.

""Pressurex pressure indicating sensor film was used by MSA for setup of ultrasonic welds for manufacturing operations,” according to industry consultant Nathan Isaacs. “Based on information obtained from Pressurex, engineers were able to make tooling adjustments to provide uniform pressure in the weld zone. This speeded setup and prevented product scrap,"" add Isaacs.

Pressurex is between 4-8 millimetres thin and is flexible, making it suitable for many curved surfaces.