Economical sheet metal stamping is a very important process in the manufacturing industry, but it is a process plagued by potential challenges. During the few fractions of a second in which a sheet of metal is pressed between two geometrically negative dies to produce a stamped part, a host of problems can occur, the most troublesome being wrinkling, tearing and springback.
For the past three years, ME Professor Galip Ulsoy and PhD. student Yongseob Lim have worked with industrial partners Troy Design and Manufacturing, Opal-RT and Ogihara America Corporation to address these challenges. The result of their labor is an intelligent computer-aided stamping system that could significantly improve the process of sheet metal stamping and alleviate many of the glitches involved in part production.
In fall 2006, Lim responded to a request from Ulsoy in search of a graduate student to help with his stamping control project. “I was interested in working with Professor Ulsoy, who was famous for his nice advising and for taking care of his students, based on comments in our Korean Society in the ME department,” said Lim.
Since January 2007, Lim and Ulsoy have developed a stamping system that uses an adaptive process controller to respond to process variations, such as material thickness and lubrication changes. “The intelligent computer-aided stamping system is equipped with 12 hydraulic-controlled actuators to adjust blank holder force, using in-process punch force sensors at four corners of the press, to improve part quality in the presence of plant variations and disturbances in production,” Lim explained.
Lim and Ulsoy’s design differs from other stamping systems currently being used, which cannot respond to disturbances or changes in plant dynamics. The need for this kind of adaptability is becoming more profound as manufactures continue to reduce the weight of automobiles and improve car crash performance by choosing lighter-weight and stronger materials, such as aluminum, magnesium, and high-strength steel alloys.
“However, these [new materials] are not as formable as mild steel, and can produce more springback and fracture problems,” said Lim. Lim and Ulsoy’s system, which has been validated through experiments in real production environments, has proven to have what it takes to tackle these important challenges.
The project is funded by a State of Michigan 21st Century Fund grant, a program seeking to “strengthen and diversify Michigan’s economic base by fostering the creation and growth of new jobs, new businesses, and new industries within the State.” Dr. Ravi Venugopal, from another industrial partner Intellicas, Inc, is pursuing the commercialization of this new technology.