Learning Module for using Dynaform® to Study the Effects of Die-Entry and Punch-Nose Radii on Drawing Cups

The new model for an entry-level engineer in the United States automotive industry is that of a design engineer, one who is capable of part design and analysis using advanced CAE tools such as solid-modeling, mechanical systems dynamics (MSD), finite element analysis (FEA), and computational fluid dynamics (CFD). Since this will require a major change and enhancement of the current undergraduate engineering curriculum, the Mechanical Engineering Department at Kettering University (formerly GMI) is developing a comprehensive set of Learning Modules that can be woven into all Mechanical Engineering courses so that students use the tools often and in various contexts to solidify their knowledge of the computational tools and meet the learning objectives of the courses. The modules will be self-paced and self-explanatory, can be used by students and faculty outside of the classroom, and include meaningful examples that use CAE and existing laboratories to study real-life problems. This paper describes one of the first prototype modules for Manufacturing and Mechanical Engineering students in a senior-level course in sheet metal forming. The students investigated the effects of changes in the die-entry radius and punch-nose radius versus depth of draw for cylindrical cups using various ring dies and flat bottom punches. The experimental data consistently showed that the die-entry radius has a very marked effect on depth while the punch-nose radius has very little effect. For a change in die-entry radius, once a minimum value has been exceeded, the material flows smoothly over the radius to generate a full depth cup. Simulation results using Dynaform® are presented that show that the experimental observations can be modeled by assigning appropriate values for the process parameters (die entry radius, clearance, friction, and binder). The Design of Experiments (DOE) method is used to develop guidelines for the selection of the process parameters for drawing cylindrical cups based on Forming Limit Diagrams from the simulations data.