Recent Investigations on Shot Peen Forming of GLARE Sheets and Rotary Peen Forming

摘要

To meet the demands of the industry like weight optimization and cost reduction new materials have been formed with the traditional Shot Peen Forming (SPF) and new peen forming processes have been developed. In this paper, SPF of sandwich sheets is investigated and the recent developments in Rotary Peen Forming (RPF) are presented. The need of lightweight structures in aeronautic engineering leads to the demand to form extensive structural parts made of new material combinations like GLARE. Usually, GLARE parts are formed using the self-forming technique. This process offers a good formability of sandwich material combinations of aluminum and glass fiber epoxy. Nevertheless, the process is very cost intensive due to the high amount of manual labor. This led to the idea to form flat stock GLARE sheets with conventional Shot Peen Forming. The results of the Shot Peen Forming of single and doubly curved GLARE sheets are presented in this paper. Furthermore, the Rotary Peen Forming process has been developed as a new peen forming process in which the shot is moved on a circular trajectory held by a flexible connection. RPF has the main advantage compared to traditional Shot Peen Forming processes that it does not need recirculation of shot particles. Hence, RPF offers a compact machine design enabling a flexible and adaptable handling. The RPF process causes localized plastic deformation just as in traditional SPF but involves tangential components which can create shear deformation in the plastic layer. Compared to traditional SPF, RPF shows different process characteristics in terms of coverage and the shape of indentations created on the surface of the workpiece. To improve the forming potential and the flexibility of the process, more degrees of freedom for the tool movement are necessary. In this paper, a new test setup using a robot is presented.