Development of automotive engine cradle by hydroforming process

Abstract

The hydrofonning technology may bring many advantages to automotive applications in terms of better structural integrity of the parts, lower cost from fewer part count, material saving, weight reduction, lower springback, improved strength and durability and design flexibility. In this study, the whole process of front sub-frame parts development by tube hydroforming using steel material having tensile strength of 440 MPa grade is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Design) to confirm hydrofonnability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape in automotive engine cradle by the hydroforming process were carefully investigated. Overall possibility of hydroformable engine cradle parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending, preforming and hydroforming. At the die design stage, all the components of prototyping tool are designed and interference with the press is examined from the point of deformed geometry and local thinning.

Role of Tool Size in Suppressing Defects in SPIF Process

“…Therefore, rigorous experimental work had to perform so as to simultaneously optimize contradictory behavior of these defects to reach a suitable value of min . r 1 In order to obtain three different levels of yield stress, the sheet was cold rolled to three levels. Cold working increases stress, but at the same time decreases the hardening exponent.…”

“…Recent change in the pattern of customer's demand has led to innovation of various new flexible manufacturing methods including hydro-forming [1][2][3][4], laser forming [5], water jet forming [6] and incremental forming. Single point incremental forming (SPIF), however due to its simplicity, has drawn great attention from manufacturers [7,8].…”

Optimization of the loading path for the tube-hydroforming process

“…The technique of hydroforming is similar to the general metalforming process; however, it is unique in that the hydraulic pressure is utilized to form a desired shape. [1][2][3][4][5][6] Also, the axial feeding is used to improve the formability of the hydroformed product. 4 In general, tube hydroforming uses a tube to form the desired shape by applying a hydraulic pressure inside the tube.…”

“…[1][2][3][4][5][6] Also, the axial feeding is used to improve the formability of the hydroformed product. 4 In general, tube hydroforming uses a tube to form the desired shape by applying a hydraulic pressure inside the tube. 5,7 Movement of the material is important to obtain the desired forming product and is dependent on the strain rate and the material properties.…”

Experimental investigations on the role of tool size in causing and controlling defects in single point incremental forming process

“…Therefore, in order to satisfy the innovative demands of market, a great deal of efforts to develop flexible forming methods has been made in the last decade. As a result of these efforts, many new forming processes such as hydroforming, [1][2][3][4] laser forming, 5 water jet forming, 6 dimple forming 7 and single point incremental forming (SPIF) 8 have been introduced. SPIF being simple and highly flexible, however, has gained the greatest popularity among all.…”