59 16 th International Research/Expert Conference ”Trends in the Development of Machinery and Associated Technology” TMT 2012, Dubai, UAE, 10-12 September 2012 MEASUREMENT AND VERIFICATION OF DEEP DRAWING FORCE IN CASE OF NON-SYMMETRIC PARTS Enes Mujic, M.Sc dd HELIOS Banovici, 75290 Banovici Bosnia and Herzegovina Mirna Nozic, Dr.-Ing University "Dzemal Bijedic", Faculty of Mechanical Engineering, 88000 Mostar Bosnia and Herzegovina Himzo Djukic, Dr.-Ing University of Mostar, Faculty of Mechanical Engineering and Informatics 88000 Mostar, Bosnia and Herzegovina ABSTRACT Deep drawing of complex, non-symmetric shapes is often related with problems with wrinkling and excessive thinning. Draw beads can be useful addition to drawing tool in such situations but its shape and positions are difficult to determine in advance. In this paper we describe experimental procedure of deep drawing force measurement in order to verify numerical simulation of deep drawing process of non-symmetric part using draw beads. Forces obtained by numerical simulations are compared with the ones obtained by specially developed resistance strain gage force sensors. We have analysed results and gave some recommendations. Keywords: deep drawing, drawbeads, finite element model, restraining force. 1. INTRODUCTION For the axially non-symmetric part (proportionally scaled wheelbarrow box in our case) we performed series of numerical simulations in order to determine appropriate geometric parameters of drawbeads. With respect to its depth, such parts belongs to intermediate deep drawing class and it is made of standard deep drawing steel DC03 according to EN10130 specifications, with sheet thickness of 0.8 mm. From experiences for such products and tool design, it is known that, frequently, there are problems in deep drawing process related to wrinkling, thinning or tearing in the flange of the part. By utilisation of drawbeads those problems can be reduced or eliminated but deep drawing tool design with drawbeads is much more complicated and its costs are much higher. In order to reduce tool design time and number of tool corrections, we use series of numerical simulations to detect possible problems in advance, with iterative improvements, proceeding to optimal deep drawing tool design. 2. PARAMETERS USED IN NUMERICAL SIMULATIONS We start with definition of 3D CAD model of working part, according to original documentation, shown in Figure 1 (a). The basic geometric parameters of drawbeads are shown in figure 1(b). Shape and size of drawbeads are defined by those parameters. We performed simulations with different drawbeads shapes and positions. The parameters that were varied are: • bead height (we use this parameter in the range of 3,4,5,and 6 mm) • bead radius (this parameter was varied with values of 2, 2.5 and 4 mm • entrance radius (the same values as bead radius) • exit radius (the same values as for entrance radius)