Topic
Hydroforming
About: Hydroforming is a research topic. Over the lifetime, 2796 publications have been published within this topic receiving 26293 citations. The topic is also known as: Bulge forming.
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Patent•
07 Mar 1994
TL;DR: A hydroforming process and apparatus for manufacturing components of a vehicle exhaust or intake manifold is described in this article. But this process is not suitable for vehicular applications, as it requires a large number of dies to form a compound bend in the pressurized tube.
Abstract: A hydroforming process and apparatus for manufacturing components of a vehicle exhaust or intake manifold. The hydroforming process is utilized to form a tubular member to the desired configuration for use in a manifold. The tubular member is loaded into a hydroform press and filled with a suitable liquid. The liquid within the tube is pressurized in order to maintain a predetermined internal fluid pressure which prevents collapse and crimping of the tube during forming. The hydroform press includes two sets of dies to form a compound bend in the pressurized tube. Upper and lower dies close on the tube first to bend the tube in a vertical plane. Horizontal dies are wedged inwardly spreading the first die set and bending the tube in a horizontal plane. As a result, a compound configuration may be placed on the tube making it suitable for use in a vehicle manifold.
25 citations
TL;DR: In this article, a comparison of 5-axis and 3-axis finish machining was made using a tilt/rotary table and the results showed that the generated 3axis tool paths are longer than the 5axis paths by at least 247%.
Abstract: The recent growth in hydroforming technology has sparked interest in alternative methods to the current conventional die manufacturing techniques. Hydroforming dies typically have shallow forming channels and open, low curvature surfaces, making them ideally suited for 5-axis machining. To fully appreciate the benefits and to properly demonstrate the capabilities of 5-axis machining for hydroforming dies, a comparison of 5-axis and 3-axis finish machining was done. Two hydroforming die insert sets were machined on a 5-axis machine with a tilt/rotary table. The tool paths for 5-axis machining were generated using custom software based on a modified form of a tool positioning strategy called the principal axis method. The quality of generated 3-axis toolpaths was verified against the machining times of a third set of die inserts, similar to those machined in 5-axis, by an independent industrial mould and die manufacturer using a 3-axis highspeed machine. A comparison of the generated 3-axis paths versus the 5-axis paths for one of the die inserts was made using total finish machining tool path lengths to eliminate differences in machines. The results show that the generated 3-axis tool paths are longer than the 5-axis paths by at least 247%. The paper discusses the different tool-path generation methods along with the geometry of cusp formation and the effect of tool selection. Methods to improve the 3-axis results are also presented.
25 citations
TL;DR: In this paper, a multi-stage tube hydroforming process was investigated by using an aluminum alloy and the optimization strategy was created and the process parameters were optimized by using useful wrinkles instead of harmful wrinkles in the pre-forming stage and in the finishing stage.
25 citations
TL;DR: In this article, the authors proposed an experimental approach to evaluate the formability of tube hydroforming under biaxial stretching through elliptical bulging. But the experimental results were limited to the right hand side of the forming limit curve (FLC).
24 citations
TL;DR: In this article, different grades and effect of their composition on elevated temperature strength, creep strength, endurance limit, and corrosion resistance are presented, and the selection of grades and stabilizing elements are critical for such applications and depend primarily on operating conditions.
Abstract: Mounting energy crisis, stringent emission law and strict safety rules have guided car manufacturers to improve strength/weight ratio of the vehicle, thereby promoting several applications of stainless steels in the car body. Moreover, use of stainless steels also improves aesthetics and minimizes life cycle cost. In automobiles, presently 45-50% of stainless steels are used in exhaust systems. To improve efficiency, complex designs are being used and performance criteria of the material are getting tougher. New techniques such as tube hydroforming are also being explored using austenitic stainless steel for the complicated designs utilizing the benefits of high ductility of these grades. Since corrosion resistance remains fundamental requirement for these applications, selection of grades and stabilizing elements are critical for such applications and depend primarily on operating conditions. Different grades and effect of their composition on elevated temperature strength, creep strength, endurance limit and corrosion resistance are presented. Stainless steels are also being used in other applications such as fuel tank, bumper, chassis for buses and trucks. With the development of new varieties of austenitic, ferritic and martensitic stainless steels, automotive industry is intensively exploring their potential.
24 citations