STRETCH ROLL FORMING

Manufacture and maintenance of aircraft, ships, light rail cars, etc., requires many structural components formed out of extrusions. Processes such as stretch forming are typically used to produce these parts, in which unique dies are required for each forming operation. This increases the cost and lead time of production. The need for dies prevents the production of spares at the maintenance site and the need to store, maintain, locate, setup, and dismantle these dies contributes significantly to the cost of producing spare parts. A revolutionary, patent-pending, discrete parts stretch forming technology uses “universal dies” to eliminate specialized tooling. With computer numerical controls, one machine can be programmed to manufacture a range of extrusions, such as former rings and stringers, that are traditionally stretch formed starting with metal extrusions. Computer simulations of one such machine have demonstrated the feasibility of this process to produce formed parts with stress residuals and geometric accuracy comparable to that achieved by stretch forming. Additionally, the simulations have shown that the parts produced by this process would be of superior quality and durability.