The influence of ultrasonic vibration on parts properties during incremental sheet forming

Abstract

The integration of ultrasonic vibration into sheet forming process can significantly reduce the forming force and bring benefits including the enhancement of surface quality, the enhancement of formability and the reduction of spring-back. However, the influencing mechanisms of the high-frequency vibration on parts properties during the incremental sheet forming (ISF) process are not well known, preventing a more efficient forming system. This paper comprehensively investigates the effects of different process parameters (vibration amplitude, step-down size, rotation speed and forming angle) on the micro-hardness, minimum thickness, forming limit and residual stress of the formed parts. First, a series of truncated pyramids were formed with an experimental platform designed for the ultrasonic-assisted incremental sheet forming. Then, micro-hardness tests, minimum thickness measurements and residual stress tests were performed for the formed parts. The results showed that the surface micro-hardness of the formed part was reduced since the vibration stress induced by the ultrasonic vibration within the material which eliminated the original internal stress. The superimposed ultrasonic vibration can effectively uniform the residual stress and thickness distribution, and improve the forming limit in the case of the small deformation rate. In addition, through the tensile fracture analysis of the formed part, it is shown that the elongation of material is improved and the elastic modulus and hardening index are decreased. The findings of the present work lay the foundation for a better integration of the ultrasonic vibration system into the incremental sheet forming process.

Keywords

Incremental sheet forming / Ultrasonic vibration / Residual stress / Forming limit

References

[1] Edward L (1967) Apparatus and process for incremental dieless forming. US Patent 3342051, 19 Sept 1967

[2] Kumar A, Gulati V, Kumar P, et al. Forming force in incremental sheet forming: a comparative analysis of the state of the art. J Braz Soc Mech Sci Eng, 2019, 41(6): 1-45.

[3] Mohanty S, Regalla SP, Daseswara Rao YV. Robot-assisted incremental sheet metal forming under the different forming condition. J Braz Soc Mech Sci Eng, 2019, 41(2): 81.

[4] Ambrogio G, Cozza V, Filice L, et al. An analytical model for improving precision in single point incremental forming. J Mater Process Technol, 2007, 191(1/3): 92-95.

[5] Boudhaouia S, Gahbiche MA, Ayed Y, et al. Experimental and numerical study of a new hybrid process: multi-point incremental forming (MPIF). Int J Mater Form, 2017, 11(6): 815-827.

[6] Li MZ, Cai ZY, Sui Z, et al. Multi-point forming technology for sheet metal. J Mater Process Technol, 2002, 129(1/3): 333-338.

[7] Li XQ, Han K, Xu P, et al. Experimental and theoretical analysis of the thickness distribution in multistage two point incremental sheet forming. Int J Adv Manuf Technol, 2020, 107(1/2): 191-203.

[8] Mohammadi A, Vanhove H, Van Bael A, et al. Towards accuracy improvement in single point incremental forming of shallow parts formed under laser assisted conditions. Int J Mater Form, 2014, 9(3): 339-351.

[9] Duflou JR, Callebaut B, Verbert J, et al. Laser assisted incremental forming: Formability and accuracy improvement. Cirp Ann-Manuf Technol, 2007, 56(1): 273-276.

[10] An ZG, Yan D, Qie JJ. Effect of process parameters on formability of a AZ31 magnesium alloy thin-walled cylindrical part formed by multistage warm single-point incremental forming. Front Mater, 2020, 7: 151.

[11] Min JY, Seim P, Storkle D, et al. Thermal modeling in electricity assisted incremental sheet forming. Int J Mater Form, 2017, 10(5): 729-739.

[12] Vahdani M, Mirnia MJ, Bakhshi-Jooybari M, et al. Electric hot incremental sheet forming of Ti-6Al-4V titanium, AA6061 aluminum, and DC01 steel sheets. Int J Adv Manuf Technol, 2019, 103(1/4): 1199-1209.

[13] Li YL, Zhai WD, Wang ZJ, et al. Investigation on the material flow and deformation behavior during ultrasonic-assisted incremental forming of straight grooves. J Mater Res Technol, 2020, 9(1): 433-454.

[14] Zhai WD, Li YL, Cheng ZN, et al. Investigation on the forming force and surface quality during ultrasonic-assisted incremental sheet forming process. Int J Adv Manuf Technol, 2020, 106(7/8): 2703-2719.

[15] Emmens WC, van den Boogaard AH. Tensile tests with bending: a mechanism for incremental forming. Int J Mater Form, 2008, 1: 1155-1158.

[16] Fan GP, Gao L. Mechanical property of Ti-6Al-4V sheet in one-sided electric hot incremental forming. Int J Adv Manuf Technol, 2014, 72(5/8): 989-994.

[17] Li YL, Chen XX, Zhai WD, et al. Effects of process parameters on thickness thinning and mechanical properties of the formed parts in incremental sheet forming. Int J Adv Manuf Technol, 2018, 98(9/12): 3071-3080.

[18] Hussain G, Gao L. A novel method to test the thinning limits of sheet metals in negative incremental forming. Int J Mach Tools Manuf, 2007, 47(3/4): 419-435.

[19] Filice L, Ambrogio G, Gaudioso M. Optimised tool-path design to reduce thinning in incremental sheet forming process. Int J Mater Form, 2013, 6(1): 173-178.

[20] Kim TJ, Yang DY. Improvement of formability for the incremental sheet metal forming process. Int J Mech Sci, 2000, 42(7): 1271-1286.

[21] Bambach M, Taleb AB, Hirt G. Strategies to improve the geometric accuracy in asymmetric single point incremental forming. Prod Eng, 2009, 3(2): 145-156.

[22] Radu C, Tampu C, Cristea I, et al. The effect of residual stresses on the accuracy of parts processed by SPIF. Mater Manuf Process, 2013, 28(5): 572-576.

[23] Radu C, Herghelegiu E, Tampu C, et al. The residual stress state generated by single point incremental forming of aluminum metal sheets. Appl Mech Mater, 2013, 371: 148-152.

[24] Singh A, Agrawal A. Investigation of surface residual stress distribution in deformation machining process for aluminum alloy. J Mater Process Technol, 2015, 225: 195-202.

[25] Jimenez I, Lopez C, Martinez-Romero O, et al. Investigation of residual stress distribution in single point incremental forming of aluminum parts by X-ray diffraction technique. Int J Adv Manuf Technol, 2017, 91(5/8): 2571-2580.

[26] Subrahmanyam A, Lingam R, Hayakawa K, et al. Experimental and numerical investigation of residual stresses in incremental forming. Mater Trans, 2020, 61(2): 228-233.

[27] Khazaali H, Fereshteh-Saniee F. A comprehensive experimental investigation on the influences of the process variables on warm incremental forming of Ti-6Al-4V titanium alloy using a simple technique. Int J Adv Manuf Technol, 2016, 87(9/12): 2911-2923.

[28] Shaolin XU, Kuriyagawa T, Shimada K. Recent advances in ultrasonic-assisted machining for the fabrication of micro/nano-textured surfaces. Front Mech Eng, 2017, 12(1): 33-45.

[29] Wang P, Wang D. Evaluation of different tool geometries in the finite element simulation of ultrasonic-assisted drilling of Ti6A14V. J Braz Soc Mech Sci Eng, 2020, 42(4): 205-210.

[30] Vahdati M, Mahdavinejad R, Amini S. Investigation of the ultrasonic vibration effect in incremental sheet metal forming process. P I Mech Eng B J Eng, 2017, 231(6): 971-982.

[31] Amini S, Gollo AH, Paktinat H. An investigation of conventional and ultrasonic-assisted incremental forming of annealed AA1050 sheet. Int J Adv Manuf Technol, 2017, 90(5/8): 1569-1578.

[32] Dnwson GR, Winsper CE, Sansome DH. Application of high and low-frequency oscillations to the plastic deformation of metal. Metal Form, 1970, 8: 234-238.

[33] Centeno G, Bagudanch I, Martinez-Donaire AJ, et al. Critical analysis of necking and fracture limit strains and forming forces in single-point incremental forming. Mater Des, 2014, 63: 20-29.

[34] Saito Y, Utsunomiya H, Tsuji N, et al. Novel ultra-high straining process for bulk materials development of the accumulative roll-bonding (ARB) process. Acta Mater, 1999, 47(2): 579-583.

[35] Long YY, Li YL, Sun J, et al. Effects of process parameters on force reduction and temperature variation during ultrasonic assisted incremental sheet forming process. Int J Adv Manuf Technol, 2018, 97(1/4): 13-24.

[36] Petch NJ. The cleavage strength of polycrystals. J Iron Steel I, 1953, 174(1): 25-28.

[37] Deshpande A, Hsu K. Acoustic energy enabled dynamic recovery in aluminium and its effects on stress evolution and post-deformation microstructure. Mat Sci Eng A Struct, 2018, 711: 62-68.

[38] Jing L, Lui G. Study on surface integrity in hard milling of hardened die steel. Mat Sci Forum, 2006, 532/533: 540-543.

Funding

National Natural Science Foundation of China(51975328)

Postdoctoral Innovation Project of Shandong Province(201701011)

Young Scholars Program of Shandong University(2018WLJH55)