The process analysis of metal stamping parts has analyzed the shape characteristics, size, and accuracy requirements of the parts based on the product numerical model and GDT diagram. Based on experience, the dangerous areas where wrinkling and cracking defects may occur during the forming process of the parts have been identified. In addition, when determining the process plan, attention should also be paid to the extreme dimensions of the parts (such as punching * small size, * small bending radius, * small deep drawing corner radius, * small hole spacing and hole edge distance, etc.), dimensional tolerances, and the impact of design standards on the stamping process.
1) The workpiece itself, the workpiece and the bed and mold do not interfere. CNC bending is a manufacturing process that involves a series of continuous bending of the sheet metal to generate the workpiece. In free V-shaped bending, the bending process is carried out sequentially and continuously. During the bending process, there should be no interference between the workpiece itself, the workpiece and the bed (worktable, slider, etc.), and the mold (concave mold, convex mold, and mold fixture), that is, no abnormal contact should occur. Otherwise, the bending process will not proceed smoothly. The non-interference condition must be met first in the process arrangement.
2) When there is a requirement for dimensional accuracy in bent parts, the selection of positioning points during bending must meet the accuracy requirements, so that dimensional deviations accumulate in the bent sections without accuracy requirements. At the same time, the process arrangement should ensure the accuracy of the bent parts. For example, in Figure 6-1, when there is a requirement for dimensional accuracy between points A and B, point B must be used as the positioning point when bending point A, and vice versa, in order to ensure the dimensional accuracy of points A and B.
In the past 20 years, domestic researchers have conducted extensive research and in-depth exploration on the theory and methods of optimizing the bending process of sheet metal workpieces. They have introduced artificial intelligence technology, artificial neural networks, genetic algorithms, object-oriented methods, and feature technology into the CAPP system, and proposed some distinctive methods. The arrangement of processes has played a great promoting and driving role. However, most of the developed systems have low practical value; Systems with practical value are limited to two-dimensional graphic display functions, but few have three-dimensional functions. Among them, representative ones include Huazhong University of Science and Technology, Huangshi Forging Machine Tool Co., Ltd., Jinan Foundry Forging Machinery Research Institute, etc. Huazhong University of Science and Technology has long been engaged in research and development of new plastic forming equipment and its computer control. During the "Seventh Five Year Plan" and "Eighth Five Year Plan" periods, we also undertook the national scientific and technological research projects "RD-W67K-125/3000 Plate Bending Processing Unit" and "Universal Numerical Control System for Forging Machine Tools". And a sheet metal workpiece bending process optimization system has been developed for CNC bending machines. The system interface is friendly, the overall structure is basically complete, and the module division is clear. However, the three-dimensional graphic display function of the workpiece has not been achieved