Optimization of forming machine stiffness for increased production accuracy

Abstract

This paper deals with the use of topology optimization in the design of mechanical forming machines. This worldwide industry sector has not seen any significant developments or changes in a long time. Yet, there is a constant effort to reduce the weight of machines. Unfortunately, significant design changes are less common in new mechanical presses than in other production machines. In this paper, topology optimization was employed to minimize the weight and maximize the stiffness of an entire 80 MN mechanical forming press. The frame of this press consists of two crossbeams and four preloaded columns. The results of the optimization were translated into new welded and cast frame designs. The main focus was on the upper and lower crossbeams. The optimization theory and parameters (the design space, objectives and variables) are presented from the computational viewpoint. The compliance objective was employed, considering the entire assembly of the press. Submodeling was used to refine the results. The loading cases considered center and off-center loads. Based on the results obtained, new designs of the crossbeams were developed. The comparison between the conventional and optimized designs demonstrates the feasibility of weight reduction and stiffness improvement (depending on the manufacturing method of the crossbeams). The new designs are more economical, environmentally-sound and suitable for production.