Research Of Design And Plasma Deposition Manufacturing Of Dies Based On Simulation

The economic globalization has brought about an increasingly fiercer competition market, which the Chinese die industries have to answer for in earnest. The traditional model of design and manufacturing has been unable to meet the requirements of Chinese die manufacturers for concurrent design and manufacturing of high-performance, long-life and complex dies. The digital concurrent design and manufacturing and the direct metal Rapid Tooling, with the advantages of new concepts, advanced methods, short process, low-cost, high quality and highly flexible, can respond quickly to market changes and customer needs. They are key factors to break the bottleneck of the development of die technology. However, related research is still in the qualitative experimental stage. There is no research on the application of concurrent die design and manufacturing. Therefore, it requires scientific theory to quantitatively guide it.Die design and rapid manufacturing are considered as organically integrated components of a whole. Systematic technical line and research programs are designed. According to drawing conditions, the dies are digitally designed and manufactured. The mechanical behaviors, wear, life and the plasma deposition manufacturing process of dies which made of different materials are studied. The important scientific basis is provided for the optimization of process parameters and technology solutions. The study contains the following three aspects:A case of automobile fender drawing die is studied by finite element method. Dies made of conventional homogeneous material and graded materials are researched and compared. Based on the rigid-plastic model of sheet and the elastic-plastic model of dies, the mechanical condition, load and dynamic evolution of sheet and dies during drawing process are simulated and analyzed. The results show that the functionally graded materials can reduce the load and stress level of the dies. Maximum equivalent stress can be reduced by 8.8%. At the same time, the quantitative values of the die stress and its distribution are given, and the stress concentration areas of the dies, which are located in die corners, the salients of the bottom and drawbeads, are qualitatively determined, which provides basic mechanical conditions for further study on the life and the damage mechanisms of die.Based on the classic Archard wear model, the surface wear, its distribution and history of drawing dies made of homogeneous materials and gradient materials are simulated by rigid-plastic finite element method. The quantitative values of the die wear and its distribution are given, and the wear concentration areas of the dies are qualitatively determined. The wear lives of the drawing dies made of different materials are accurately predicted. The results show that the functionally graded materials can reduce the wear, and extend the service life of the die by 55%, fully bring out the latent potentialities of materials, shorten the die manufacturing period by 40%, improve productivity and cut down cost of production. It provides a reliable theoretical basis for the design of the drawing die made of graded materials, and can be used as important parameters of the evaluation of the die.The mechanical and wear simulation results coincide with the experimental verifications and the actual production situations. Most recent research works focused on extrusion dies or forging dies, and almost no research of mechanical analysis and wear prediction of large stamping dies have been involved.Based on the plasma heat source moving model and the thermal elastic-plastic mechanical model of three-dimensional nonlinear transient field, the parametric design language (APDL) programs of plasma deposition manufacturing are developed. The three-dimensional transient fields of plasma deposition manufacturing process are studied by finite element method. The influence of the main process parameters on the forming quality, and the mechanism of residual stress and deformation are analyzed. It provides the theoretical basis and the right guidance on the technology program of plasma deposition manufacturing and the quality control of metal dies. The plasma deposition manufacturing processes of a straight-walled sheet metal part, an aircraft surface stretch die and a fender drawing dies are simulated and verified. The experimental results accord with the simulation results, and it proves that the present simulation method is correct and practical. The results indicated that the residence time of the part in high temperature can be reduced by 65.6% with water cooling substrate; the residual stress in the corresponding regions of part can be decreased by 60.8% and 65.8%; the strain at both ends of connection between part and substrate can be decreased 53.4%; the strain at local areas can be reduced by 70% and 22.4% with unloading slots under substrate. Most recent research works focused on hydrogen tungsten arc welding or metal inert-gas welding, and no researcher except our group has reported the studies on the three-dimensional transient fields of plasma deposition manufacturing process.Before design and manufacturing, the influence of the die materials on the sheet metal forming, the operation behavior, the mechanical condition, the wear of the dies can be predicted, and the feasibility and reliability of the structure design and material design of the dies can be verified. The results provide theoretical basis for the design, the plasma deposition manufacturing and the quality control of dies according to drawing conditions and direct metal rapid tooling process. And finally, it advanced the practical course of low-cost rapid manufacturing of high-performance, long-life and complex die.