Plastic Assembly News

Dukane Advances the Ultrasonic Delivery System

Ultrasonic welding has been in existence as an assembly process for over 40 years. As a method of bonding plastics, it has become one of the most accepted processes because it is clean, energy efficient and fast.

The birth of ultrasonic welding was discovered quite by accident, as many modern marvels are similarly invented. In the early years of the technology, the energy was applied to the plastic part by an operator who would manually pull the lever arm of an arbor press, which held an ultrasonic transducer and horn. In those days, the pressure would vary during the process and the amplitude would droop tremendously as the load was applied to the material. The process control was crude, but an industry had been launched.

During the late 1960’s and early 1970’s, ultrasonic machines were produced with pneumatic delivery systems and manufacturers called these components, presses or actuators. As a means for delivering the converter and the horn to the plastic, these systems were significantly advanced when compared to the previous hand controlled choice. In the 1980’s and 1990’s new products were produced that controlled the amount of energy delivered to the plastic. Ultrasonic welding machines were developed allowing welding by distance. Other significant electronic advances were made to the power supplies to control amplitude and stay current with the digital revolution. However, the delivery system for bringing the vibrating horn to the plastic has continued to be the standard actuator or press comprised of pneumatic components.

Back in the mid 90’s I predicted that I would be surprised if by the year 2000 manufacturers of ultrasonic plastic welding equipment had not incorporated the servo controlled technology into their standard product line. It just made sense. These innovative machine motion control systems provide the ability to control and profile force with the acceleration and deceleration features embellishing the welding process. I thought that servo controlled ultrasonic systems would become as common place as servo controlled injection molding machines.

Wow was I way too early with my prediction. However, one manufacturer has finally seen the light. Dukane has developed a new delivery system that looks like it could provide users a degree of control not previously realized in the industry. I am sure it is expensive and not meant for all applications, but for those companies looking for precise control of the process it is probably worth investigating.

Gary Clodfelter
Plastic Assembly Technologies, Inc.

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