This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Numerical Investigation of Optimal Rooftop Punch Shape for Force Reduction and Dimensional Accuracy Control
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 02, 2019 by SAE International in United States
Annotation ability available
The rooftop punch is proposed to reduce the maximum cutting force during the trimming operation for advanced high strength steels (AHSS), by introducing a shearing angle at the tool edge. However, such non-simultaneous shearing mechanism results in the inconsistent deformation around the hole perimeter, and consequently affects the dimensional accuracy of the trimmed hole. A numerical study was conducted to investigate the effects of punch tipping angle and tipping heights on the force reduction and dimensional discrepancies. The 60mm hole punching operation for DP 1180 (1.2mm) material was simulated with finite element analysis. The tipping height was reduced by introducing flat portions to the rooftop punch and it can mitigate the material deformation difference before trimming. The results showed tipping height played a significant role of dimensional accuracy control by adopting small tipping angle and broad flat portions. However, such geometric combination could increase the maximum shearing load at the same time. Additionally, a concave rooftop punch shape was also evaluated to compare with the conventional convex rooftop punch.
CitationJia, H., Pu, C., Burton, J., Zhu, F. et al., "Numerical Investigation of Optimal Rooftop Punch Shape for Force Reduction and Dimensional Accuracy Control," SAE Technical Paper 2019-01-1091, 2019, https://doi.org/10.4271/2019-01-1091.
- Pu, C. and Gao, Y., “Crystal Plasticity Analysis of Stress Partitioning Mechanisms and Their Microstructural Dependence in Advanced Steels,” J. Appl. Mech. 82(3):031003, 2015, doi:10.1115/1.4029552.
- Karjalainen, J.A., Mäntyjärvi, K., and Juuso, M., “Punching Force Reduction with Wave-Formed Tools,” Key Eng. Mater. 344:209-216, 2007, doi:10.4028/www.scientific.net/KEM.344.209.
- Shih, H.-C., Zhou, D., and Konopinski, B., “Effects of Punch Configuration on the AHSS Edge Stretchability,” SAE Int. J. Engines 10:2017, 2051-2056.
- Pu, C., Zhou, D., Makrygiannis, P., Wu, W. et al., “A Comprehensive Study of Hole Punching Force for AHSS,” SAE Technical Paper 2018-01-0802, 2018, doi:10.4271/2018-01-0802.
- Pu, C., Jia, Y., Zhou, D., Makrygiannis, P. et al., “Effects of Punch Shapes and Cutting Configurations on the Dimensional Accuracy of Punched Holes on an AHSS Sheet,” SAE Technical Paper 2018-01-0800, 2018, doi:10.4271/2018-01-0800.
- Mackensen, A., Golle, M., Golle, R., and Hoffmann, H., “Force Reduction during Blanking Operations of AHSS Sheet Materials,” CIRP Ann. - Manuf. Technol. 59(1):283-286, 2010, doi:10.1007/978-3-662-46312-3_32.
- Kalpakjian, S. and Schmid, S.R., Manufacturing Engineering and Technology (Upper Saddle River, NJ: Pearson, 2014). ISBN:0133128741.
- Kadarno, P., Mori, K.-I., Abe, Y., and Abe, T., “Punching Process Including Thickening of Hole Edge for Improvement of Fatigue Strength of Ultra-High Strength Steel Sheet,” Manuf. Rev. 1:4, 2014, doi:10.1051/mfreview/2014003.
- Subramonian, S., Altan, T., Ciocirlan, B., and Campbell, C., “Optimum Selection of Variable Punch-Die Clearance to Improve Tool Life in Blanking Non-Symmetric Shapes,” Int. J. Mach. Tools Manuf. 75:63-71, 2013, doi:10.1016/j.ijmachtools.2013.09.004.
- Wang, K., Greve, L., and Wierzbicki, T., “FE Simulation of Edge Fracture Considering Pre-Damage from Blanking Process,” Int. J. Solids Struct. 71:206-218, 2015, doi:10.1016/j.ijsolstr.2015.06.023.
- Sartkulvanich, P., Kroenauer, B., Golle, R., Konieczny, A., and Altan, T., “Finite Element Analysis of the Effect of Blanked Edge Quality upon Stretch Flanging of AHSS,” CIRP Ann. - Manuf. Technol. 59(1):279-282, 2010, doi:10.1016/j.cirp.2010.03.108.
- Jia, Y. and Bai, Y., “Ductile Fracture Prediction for Metal Sheets Using All-Strain-Based Anisotropic eMMC Model,” Int. J. Mech. Sci. 115-116:516-531, 2016, doi:10.1016/j.ijmecsci.2016.07.022.
- Kutuniva, K., Karjalainen, J.A., and Mäntyjärvi, K., “Effect of Convex Sheared Punch Geometry on Cutting Force of Ultra-High-Strength Steel,” Key Eng. Mater. 504-506:1359-1364, 2012, doi:10.4028/www.scientific.net/KEM.504-506.1359.
- Jia, Y., Wang, Y., and Bai, Y., “A New Combined Isotropic, Kinematic and Cross Hardening Model for Advanced High Strength Steel under Non-Linear Strain Loading Path,” SAE Int. J. Engines 10(2):382-390, 2017, doi:10.4271/2017-01-0367.
- Jia, Y. and Bai, Y., “Experimental Study on the Mechanical Properties of AZ31B-H24 Magnesium Alloy Sheets under Various Loading Conditions,” Int. J. Fract. 197(1):25-48, 2016.