Proceedings of the
World Congress on Micro and Nano Manufacturing (WCMNM 2022 )
19–22 September 2022, Lueven, Belgium
doi:10.3850/978-981-18-5180-3_RP66-0042
Numerical Study of Grain Size Affected Deformation Behavior in Two-Stage Micro Deep Drawing using CPFEM
Department of Mechanical Engineering, Research Institute for Advanced Manufacturing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
ABSTRACT
With the continuous development of the crystal plasticity finite element method (CPFEM) and its improvement of modeling accuracy, CPFEM has been widely used in the study of complex microforming processes considering more issues such as size effect. However, there are still critical problems that need to be addressed in applying CPFEM to study micro-scaled forming complicated parts and structures, such as large element distortion and low computational efficiency. In this study, a two-stage micro deep drawing process was chosen as a case study to investigate the grain size effect on deformation behavior aided by CPFEM-based simulation. It is revealed that the two stages can significantly increase the drawing ratio. The deformation load is increased with the decreasing grain size, and for the copper blank with a grain size of 25.5 μm, there are two peaks in stage I. After stage II, the surface quality of the part is improved. From the modeling aspect, the CPFEM model can predict the thickness distribution of the formed cup well and the model accuracy can be improved by taking into account the elastic springback. In addition, the CPFEM model was able to predict surface roughness with acceptable accuracy. This study thus enriches the understanding of the two-stage deep drawing process and provides a reliable method for accurate prediction of the shape and surface roughness of the microformed cup.
Keywords: CPFEM, Grain Size Effect, Two-Stage Micro Deep Drawing, Deformation Behavior.
Department of Mechanical Engineering, Research Institute for Advanced Manufacturing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
ABSTRACT
With the continuous development of the crystal plasticity finite element method (CPFEM) and its improvement of modeling accuracy, CPFEM has been widely used in the study of complex microforming processes considering more issues such as size effect. However, there are still critical problems that need to be addressed in applying CPFEM to study micro-scaled forming complicated parts and structures, such as large element distortion and low computational efficiency. In this study, a two-stage micro deep drawing process was chosen as a case study to investigate the grain size effect on deformation behavior aided by CPFEM-based simulation. It is revealed that the two stages can significantly increase the drawing ratio. The deformation load is increased with the decreasing grain size, and for the copper blank with a grain size of 25.5 μm, there are two peaks in stage I. After stage II, the surface quality of the part is improved. From the modeling aspect, the CPFEM model can predict the thickness distribution of the formed cup well and the model accuracy can be improved by taking into account the elastic springback. In addition, the CPFEM model was able to predict surface roughness with acceptable accuracy. This study thus enriches the understanding of the two-stage deep drawing process and provides a reliable method for accurate prediction of the shape and surface roughness of the microformed cup.
Keywords: CPFEM, Grain Size Effect, Two-Stage Micro Deep Drawing, Deformation Behavior.
