Papers by Keyword: Multi-Point Forming (MPF)

Abstract: As a new technique to form sheet metal parts, Multi-point forming (MPF) also can be used on bending aluminum alloy profile. Since the Multi-Point Die (MPD) which replaces the traditional solid bending die is composed of many discrete punch elements, dimples always occur on the plate of profiles. To eliminate the dimpling defects, numerical simulation of the bending process with A6N01S-T5 aluminum alloy hollow profile using MPD were conducted. By comparing the bending effects on MPD with different size of punch elements and with different kind of elastic cushion, reasonable forming parameters were obtained. Pressing of Aluminum alloy profile with different radii on the MPD and solid die were simulated. The cross-section distortion indicated that the aluminum alloy profile can be formed with MPF technique while it has the advantage of flexibility. For the profile with large deformation, multi-step MPF method is a better choice due to its rapid reconfigurable characteristic.

Abstract: Multi-point forming (MPF) is an advanced flexible manufacturing technology for three-dimensional sheet metal forming. The substance of MPF is replacing the conventional solid dies by a set of discrete punches called punch group. Due to the discrete contacts between the workpiece and punches, the dimple defects occurred, which are inevitable and particular for MPF. In this study, the analysis of the deformation features of the dimple defects was implemented. The dynamic explicit finite element method was chosen to implement the simulation of MPF process. The influencing factors of the surface defects were researched. The relevant experiment was implemented, and it verified that the forming defects decreased with the increasing of the thickness of metal plate and the objective surface curvature radius.

Abstract: The forming and springback of sail surface during the multi-point forming under force-displacement separated control (MPF-FD) was studied. Numerical simulation method was adopted to study the springback of sail surfaces with different radius, sheet thicknesses and forming forces. The results show that the springbacks on two directions influence each other. The springback on the bigger radius direction is on the leading role, and will influence that on the smaller direction. On the direction of the bigger radius, the springback is decreased with the increase of sheet thickness, forming force and decrease of the radius. On the direction of the smaller radius, the springback is decreased with the decrease of the sheet thickness and the increase of the forming force, and the radius has a small impact on springback.

Abstract: Multi-point forming (MPF) is an advanced flexible manufacturing technology for three-dimensional sheet metal forming. The substance of MPF is replacing the conventional solid dies by a set of discrete punches called ‘‘punch group’’. Because the reconfigurable discrete punches are used, part manufacturing costs are reduced and manufacturing time is shortened. However due to the discrete contacts between the workpiece and punches, the dimple defects occurred, which are inevitable and particular for MPF. For thick plate, the surface defect is the mainly dimple defect during its MPF process. In this study, elastic cushion was proposed to prevent these surface defects. The dynamic explicit finite element method was chosen to implement the simulation of MPF process. The Hill’s anisotropic yield criterion was used to describe the workpiece material behavior, and the elastic cushion was described with using the hyperelastic material model. The method to determine each punch position to construct forming surface was introduced. The MPF process with and without using elastic cushion was simulated to study the effect of the elastic cushion on preventing the surface defects. The relevant experiment was implemented, and it verified that the elastic cushion is effective method to suppress the surface defects during the thick plate MPF process. Keyword: flexible forming process (FFP), elastic cushion, surface defects, multi-point forming (MPF), thick plate, numerical simulation