S. Supriadi1,*, T. Furushima2 and K. Manabe3
1 Dept. of Mechanical Engineering, Universitas Indonesia, Kampus UI Depok, Indonesia
2 Dept. Mechanical and Bio-functional Systems, Tokyo University, 3-8-1 Komaba, Meguro-ku, Tokyo, Japan
3 Dept. of Mechanical Systems Engineering, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino-shi, Tokyo, Japan
Keywords: Bellows forming, Vision-based sensor, Fuzzy control, Semi-dieless forming.
Abstract
A novel semi-dieless bellows forming process by local heating and axial compression has been developed in recent years [1-2]. However, this technique has high sensitivity to the processing conditions and several disturbances because of the absence of dies. Therefore, the product quality mainly depends on the temperature distribution and compression ratio in processing variable. A finite element model verified unstable bellows formation produce under temperature variation by unstable heating or cooling [2]. Adjustment of compression speed is sufficient to compensate the effect of temperature variation on bellows formation. Therefore, it is necessary to apply real-time process for this process to obtain accurate and precise bellows.
In this paper, a vision-based fuzzy control is proposed to control bellows formation. Since semi-dieless bellows forming is an unsteady and complex deformation process, the application of image processing technology is suitable for sensing the process because of the possible wide analysis area afforded by applying multi-sectional measuring.
A horizontal dieless drawing machine is utilized in this work. Local heating is achieved using a high-frequency induction heating apparatus with maximum power is 2kW at 2.2 MHz oscillation frequency. A vision sensing algorithm is developed to monitor the bellows height from the captured images by A CCD camera with infrared filter [3]. An adaptive fuzzy control system is capable of adjusting compression speed appropriately by evaluating bellows formation progress.
Figure 1. Implementation of the adaptive fuzzy controller for semi-dieless bellows forming technique.
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The output from the adaptive fuzzy controller are simultaneously corrected compression speed paths guide bellows formation following deformation references. The results show that the defect free of bellows with consistent bellows height accuracy can be achieved by applying adaptive fuzzy control and valid for different processing conditions.
REFERENCES
[1] Furushima, T., Hung, N.Q., Manabe, K., Sasaki, O., 2012, Development of Semi-dieless Metal Bellows Forming Process, Journal of the Japan Society for Technology of Plasticity 53, pp. 251-255.
[2] Supriadi, S., Hung, N.Q., Furushima, T., Manabe, K., 2011, A Novel Dieless Bellows Forming Process Using Local Heating Technique, Steel research international, pp.
950-955.
[3] Supriadi, S., Furushima, T., Manabe, K., 2012, Real-Time process control system of dieless tube drawing with an image processing approach, Materials Transactions, 53, 862-869.
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Effect of Deformation Path in Forming 3D Closed-Section Parts from Sheet Metal
Masahiko Sato1,*, Masaaki Mizumura2, Tohru Yoshida1 Yukihisa Kuriyama3, Katsuyuki Suzuki3 and Atsushi Tomizawa4
1 Nippon Steel Corporation, Futtsu 293-0011, Japan
2 Nippon Steel Technology Co., Ltd., Futtsu 293-0011, Japan
3 The University of Tokyo, Bunkyo-ku 113-8656, Japan
4 Komatsu University, Komatsu 923-8511, Japan
Keywords: Sheet metal forming, Closed section, Deformation behavior, Deformation path.
Abstract
The automobile industry demands lighter car bodies and higher strength in order to meet stricter environmental controls on exhaust emissions and legal regulations on collision safety improvement. To contribute to meeting these demands, the application of closed-section parts to car bodies is advancing [1, 2]. Since closed-section parts are good in rigidity and strength per unit weight, lighter, stronger and more rigid car bodies can be achieved. Most conventional closed section parts are fabricated from tubular blanks such as electric welded steel pipes, however, it is difficult to form a part that significantly varies in sectional circumferential length because an electric welded steel pipe has a uniform cross section in the longitudinal direction.
The aim in this research is to establish a technology (direct sheet forming) that allows the formation of complicated 3D-shaped closed-section parts directly from sheets. It is expected to form closed-section parts with large expansion of the circumferential length by direct sheet forming. In this paper, direct sheet forming of horn tubes, curved circular tubes and curved conical tubes is discussed (Figure 1). They are one of the typical shapes for automotive parts.
First, deformation types in the basic forming processes of each tube are clarified by using the results of forming experiments and FEM simulations [3, 4]. Next, on the basis of the discussion in deformation types, effect of the deformation path is investigated.
While the horn tube is formed through two processes, by the detailed observation focusing on stretch and shrink in the longitudinal direction, each process can be broken down into five deformation types. The deformation types of the horn tube are uniform bending of sheet, stretch flanging, axial bending of U-section, deformation into double curved surface and plane-strain compression. On the other hand, curved circular tubes and curved conical tubes are formed with the same three processes, and the processes can be broken down into same four deformation types. The deformation types of the curved circular tube and the curved conical tube are bending of sheet, axial bending of U-section, shrink flanging and plane-strain compression.
Since the discussion in this work focuses on the tubular parts with changing of the circumferential length and axial direction curvature, the main difference in the deformation path is whether the deformation in the circumferential direction or the longitudinal direction precedes. It is also possible to form in multi processes by combining circumferential and longitudinal deformation. The shape of sheet in the intermediate process can be expressed as a combination of longitudinal curvature and circumferential curvature (Figure 2). To indicate the difference between deformation paths, parameter α = κB1/κB2 is proposed. κB1 and κB2 are longitudinal curvatures at the bottom portion of the intermediate and final shape of sheet.
Parameter α is applied unifiedly for all three kinds of tubes (horn tube, curved circular tube and curved conical tube). It is clarified that, by using the parameter α, the strain induced in the forming can be also organized. That is, as increasing of parameter α, stretch strain at the edge
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portion of each tube increases. On the other hand, compression strain at the bottom portion decreases. Forming defects are avoided by the designing of dies with appropriate range of parameter α.
Figure 1: Basic forming processes.
Figure 2: Schematic image of the variation of deformation path.
REFERENCES
[1] M. Mizumura, O. Honda, T. Yoshida, K. Iguchi and Y. Kuriyama, 2004, Development of Hydroforming Technology, Nippon Steel Technical Report, 380, pp. 101-105.
[2] A. Tomizawa, M. Uchida, H. Kurokawa, M. Kojima and S. Inoue, 2008, Development of Hydroforming Technologies in Sumitomo, Hydroforming of Sheets, Tubes and Profiles 5, Conference proceedings, pp. 45-60.
[3] M. Sato, M. Mizumura, T. Yoshida, Y. Kuriyama, K. Suzuki and A. Tomizawa, 2019, Deformation Type in Forming of Horn Tubes: Fundamental Research for Forming of Closed-Section Parts from Sheet Metal, Materials Transactions, 60-4, pp. 538-543.
[4] M. Sato, M. Mizumura, Y. Kuriyama, K. Suzuki and A. Tomizawa, 2018, Deformation Type in Forming of Curved Circular Tubes - Fundamental Research for Forming of Closed-Section Parts from Sheet Metal II -, Journal of the Japan Society for Technoloty of Plasticity, 59-695, pp. 229-234.
horn tube
curved circular tube
curved conical tube
blank
product A
C
B
A: circumferential precedence path B: longitudinal precedence path C: combination path
circumferential curvature
longitudinal curvature longitudinal
curvature circumferential curvature
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