Papers by Keyword: Rectangular Box

Abstract: The principle of NC incremental sheet metal forming as well as the process planning, experiment of the square conical box forming are presented. Because the deformation of sheet metal only occurs around the tool head and the deformed region is subjected to stretch deformation and thins, and surface area increases. Sheet metal forming stepwise is to lead to the whole sheet metal deformation. The sine law indicates that the thickness of the square conical box wall is close to zero when the half-apex angle of the square conical box wall is close to zero. Therefore, we must know the forming limit half-apex angle to ensure that the forming can be carried out successfully, i.e., to ensure that the deformed region with a certain thickness will not fracture. It will succeed in square conical box incremental forming in a single tool-path if the forming is carried out with an angle which is larger than the forming limit half-apex angle. The fracture in the forming component can be avoided by these methods. A square conical box of uniform wall-thickness can be formed by NC incremental forming process. The thickness of deformation area is increased by increasing half-apex angle. The wrinkle in the forming component can be avoided by these methods.

Abstract: Blanker holder force (BHF) is one of the important parameters in sheet metal forming process, which is loaded by blanker holder in order to avoid wrinkling. With the development of technology, segmented blanker holder is applied to complicated product forming in order to improve the parts quality. On the basis of analyzing the character of rectangle box forming, the blank holder was divided eight portions, including 2 long straight segments, 2 short straight segments and 4 corners, which each part can separately move. Then the forming simulation of the low carbon steel rectangular box with segmented constant BHF was conducted using orthogonal experiment and considering test conditions. After the results were analyzed according to the thinnest level of the parts, the influence of the segmented blank holder on rectangular box forming was obtained. It indicates that the segmented blank holder has the ability of the local control to sheet metal forming, and can effectively adjust material flow and the strain distribution.

Abstract: The form of blank holder and the manner of blank holder force (BHF) on the complicated parts forming are very important. The blank holder of rectangle box forming was divided long straight segments, short straight segments and corners. The forming process simulation of rectangular box was conducted by FEM based on explicit algorithm, including single-piece blank holder with constant BHF, single-piece blank holder with variable BHF, segmented blank holder with constant BHF, segmented blank holder with variable BHF. The results were analyzed according to the thinnest level of the parts. The displacement in the Z direction of blank holder in the simulation was considered, and the method of determining segmented variable blank holder force (VBHF) was proposed. Finally rectangular box was obtained by rectangular box drawing system of segmented variable BHF on the basis of the simulation result.

Abstract: The sheet forming simulation of rectangular box was conducted by finite element method (FEM), the forming process experiment, further, was investigated, so as to understand the effect of the form of blank holder and the manner of blank holder force (BHF) on the complicated parts forming. In my study, a kind of low carbon steel was investigated, and its mechanical properties were obtained by simple tension tests. The outermost contour of the blank shape was determined by “one step method”. Furthermore, the finite element model was constructed by ANSYS parametric design language (APDL), which has characteristic of grid meshing by Belytschko-Tsay (BT) shell element, applying anisotropic constitutive equation of Barlat yield criterion, dealing contact by penalty function method and using adaptive mesh algorithm in the simulation process. Then the forming process simulation of rectangular box with segmented variable BHF was conducted. On the basis of analyzing the work principle and technical parameters of XP3CEF-100 hydraulic press, the rectangular box drawing system of segmented VBHF was established, which was made of hydraulic press, rectangular box drawing die of segmented blank holder, hydraulic part of blank holder and control part. Finally the low carbon steel forming tests were fulfilled by the rectangular box drawing system on the basis of the simulation result.

Abstract: Press forging of magnesium alloy AZ31 sheets was investigated in this paper. The typical component, a rectangular box with bosses at the bottom was formed. The experimental results show that the magnesium alloy sheets are suitable for press forging. The bosses and the rectangular box can be formed synchronously for 2 mm or 3 mm thick sheets when the punch temperature is 250 °C. By experimentation and numerical simulation, the effects of process parameters on material flow were analyzed, including the temperature, the die shape, the blank size, the lubrication manners and the friction condition.

Abstract: The extruded sheets were prepared at the temperature between 350ıand 400ı, and the magnesium alloy sheet was manufactured by a new method, cross rolling, in which the rolling direction was changed in each pass. At the time, deep drawing of magnesium alloy sheet was investigated at elevated temperatures. The results show that the sheet has refined-grain by cross-rolling after it was annealed at 250ı, and the formability is significantly improved at lower temperatures, which is superior to the extruded sheet and the one-way rolled sheet. Deep drawing of magnesium alloy was performed successfully, and cylindrical cup of limited drawing ratio (LDR) 2.6 and 35 mm deep rectangular box (65ı50) was achieved at the lower temperature of 170ı. The different types of fracture were analyzed and reasonable parameters were determined.