Research On Rapid Production Of Mould Using Arc Spray Forming

Mould market is very large home and abroad, and the speed of products alternation is the key factor in competition. Arc spray forming provides a new method to produce mould rapidly, and its merits are outstanding: low cost, simple technics, high efficiency of wire deposition, good replication effect, and particularly, it can cut the time sharply from mould preproduction to production. With the progress of research and application, the technology will play an important role in manufacture field.There have been already some researches on arc spray forming now, but the spray material is mostly concentrated on metal or alloy with low melting point, and the mould formed by such material has poor wear-resistant and short lifespan. Meanwhile, the corresponding spray process is directly done on prototype or on plaster model which is used for replicating prototype. For improving the performance of mould in use, stainless steel material with high melting point is sprayed in the dissertation, and ceramic model is used for replicating prototype, then it can endure the high temperature impact during arc spraying. Moreover, a series of technical problems in the process of mould production have also been studied. The main work and conclusions in the dissertation are as below:The FEM (Finite Element Method) model of the spray coating is established for temperature and stress analysis, and the compositive effects of thermal conduction, thermal convection, and thremal radiation are all considered, then the thermal-structural coupling analysis of the coating is carried out. Moreover, the process of the coating which grows layer by layer is simulated elementarily. Below three different preheated temperatures of substrate, temperature-field distribution of the coating is laid out; and deformation rule is found out, which meets experiment well; then stress-field distribution is studied particularly, especially for the key position which is prone to warp, the changing trend of the stress is analyzed in detail.The technical processes of ceramic-model forming are studied, and then the usual technical problems are explained. Finally, the dimension precision of ceramic model is evaluated from three aspects: demould time, activator content, and water content. The results indicate that: the dimension of ceramic model is steady, and the replication effect is fine, then all these work lays a firm foundation for the latter spray forming procedure.Aimed at stainless material with high melting-point, the influence rule of spray current, atomized air pressure, and spray distance on the state of melt particles is studies, and each good technical parameter is found out. Moreover, such technics as spray mould disposing,spray forming, backing, demouiding, and post treatment are all discussed, then a canteen mould is made following these procedures.Along with further research on key technics in arc spray forming, the technology will be widely used for both injecting mould and punching mould, and there will be broad market foreground for its application.