Combined Sheet and Bulk Forming of High Value Added Components in Manufacturing
The combined sheet and bulk forming process is a key technology for the near-net-shape forming of lightweight metal components with thin and multiwall thickness. In this forming process, bulk forming process, i.e., a compressive forming process, is applied to the sheet or plate workpiece in combination with the conventional sheet forming (stamping) process to minimize the material waste and manufacturing cost. “Spin forming” (flow forming, shear forming) as well as “combined stamping and forging” are key technologies in this type of the process.
The flow forming process can reduce the wall thickness of rotating cylindrical hollow workpiece into an intended value incrementally, and shear forming can form various kinds of conical/semispherical/cup-shaped hollow components from flat disk-shaped workpiece of sheet metal. The advantages of spin forming are low cost, simple tooling, easy lubrication during forming, high flexibility in forming, and applicability to cold forming of high-strength and difficult-to-form materials. The optimization of the forming process, forming parameters, tooling design, and initial workpiece design is required for successful spin forming.
The combined stamping and forging process includes the local compression of workpiece in its thickness direction for reducing the wall thickness locally in combination with some forming mode of conventional stamping of sheet metal. In this process, various kinds of thin-walled 2D/3D components with multi thicknesses, ribs, pins, and webs can be formed in near net shape from sheet workpiece of uniform thickness. The optimizations in forming sequence in multistep forming and tooling design are essential for successful forming practice.
KeywordsDeep Drawing Metal Flow Frictional Condition Small Cone Angle Major Process Parameter
- ASM INTERNATIONAL (1988) Metals handbook, 9th edn., vol 14, Forming and forging. ASM, Ohio, pp 599–604, 675–679Google Scholar
- Danno A, Fong KS, Wong CC (2011) Effects of forming conditions on diameter accuracies of short cylindrical hollow cup after forward flow forming. In: Proceedings of the 10th international conference on technology of plasticity (ICTP2011), IBF (RWTH Aachen) & ILU (TU Dortmund), Germany, pp 574–579Google Scholar
- Hayama M (1981) Principles of rotary metal working process (in Japanese). Kindai Henshu, Japan, pp 305–306Google Scholar
- Leifeld Metal Spinning AG (2012) Website. http://www.leifeldms.de/en/home.html. Accessed 16 Nov 2012
- Merklein M, Tekkaya AE, Brosius A, Opel S, Koch J (2011b) Overview on sheet-bulk metal forming process. In: Proceedings of the 10th international conference on technology of plasticity (ICTP2011), IBF (RWTH Aachen) & ILU (TU Dortmund), Germany, pp 1109–1114Google Scholar
- Nakano T (2001) Compound technology of sheet metal forming and cold forging. J Jpn Soc Technol Plast 42(484):388–392 (in Japanese)Google Scholar
- Nakano T, Ashihara K, Ishinaga N, Imura T, Toyama Y (2006) Development of combined forming of cold forging and thick sheet metal forming. J Jpn Soc Technol Plast 47(551):1146–1150 (in Japanese)Google Scholar
- Nihon Spindle Mfg. Co., Ltd. (2012) Website. http://www.spindle.co.jp/en/index.html. Accessed 16 Nov 2012
- Oyachi Y, Allwood J M (2011) Characterizing the class of local metal sheet thickening processes. In: Steel research international, special edition: 10th international conference on technology of plasticity, ICTP2011, IBF (RWTH Aachen) & ILU (TU Dortmund), Germany, pp 1025–1030Google Scholar
- Thomsen EG, Yang CT, Kobayashi S (1965) Mechanics of plastic deformation in metal processing. Macmillan, New YorkGoogle Scholar
- WF Maschinenbau und Blechformtechnik GmbH. (2012) Website. http://www.wf-maschinenbau.com/englisch/index.php. Accessed 16 Nov 2012
- Wong CC, Danno A, Fong KS (2010) Study on the deformation behavior in the flow forming of cylindrical cups using finite element method. Steel Res 81(9):1002–1006 (Proc. 13th Intern, Conf. on Metal Forming)Google Scholar
- Yang H, Li HW, Fan XG, Sun ZC, Zhang DW, Guo LG, Li H, Zhan M (2011) Technology for advanced forming of large-scale complex-structure titanium components. In: Proceedings of the 10th international conference on technology of plasticity (ICTP2011), IBF (RWTH Aachen) & ILU (TU Dortmund), Germany, pp 115–120Google Scholar