Ultrasonic Welding (Solid State Bonding) Of Aircraft Structure Fact Or Fancy

During the past few years structural ultrasonic welding has moved out of the laboratory and into commercial industries, and is now beginning to move into the aerospace industry. The ultrasonic welding process, in reality solid state bonding, has provided savings in labor, materials, and input energy, as well as increased production rates in commercial industries. Accordingly, AVRADCOM (formerly AVSCOM) funded the Sonobond Corporation and Hughes Helicopters for one year (July'76 to July'77) to verify that ultrasonic welding would be an effective production technique when applied to helicopter secondary structures. This paper summarizes the funded one-year program and presents data to show that ultrasonic welding is indeed a very cost-effective manufacturing technique. Potential cost savings are presented along with the optimized bonding technique established. Highlights of the paper are: 1. Discussion of how an AAEI secondary structural component was selected for ultrasonic welding. 2. Cost and weight comparison of manufacturing an AAH secondary structural component using the conventional bonding technque and the ultrasonic welding process. 3. Description of the Hughes Helicopters ultrasonic welding process specification, a requirement of the one-year program. 4. Discussion of the method used to optimize the welding parameters - clamping force, welding duration, and electrical power. In summary, the generation of the process specification, which subsequently may become a military specification, will permit ultrasonic welding to be used throughout the aerospace industry. This process, while not new, has never previously been used on a production aircraft.