Optimization Of Mold Material And Wax Mold Molding Process Parameters Of Investment Casting

Chinese economy has entered a period of rapid development since twenty-first Century, precision casting technology has been rapidly developing in the field of industry with the science and technology in the booming time. In the precise investment casting process, the final product size precision directly depend on and influenced by the dimensional accuracy of wax mold. This paper aims at optimizing the wax mold quality by choosing the raw material of the medium temperature mold material of investment casting, optimizing the formulation design and molding process parameters, and so on. Finally, improving the casting precision, providing a reference for related researchers and manufacturers. The main contents and conclusions are as follows:Firstly, this paper selects paraffin wax, ceresin wax and rosin as the raw material in the preparation of paraffin-ceresin wax medium temperature mold material formulation as the research object according to the actual production experience. Designing and studying the mold materials with the different raw material compositions, then, measuring the mold material shrinkage rate, bending strength, hardness, melting point and viscosity of each group mold material. The test results show that, the mold material, comprehensive performance is the best when it contents ceresin wax 50%, paraffin wax 40%, rosin 10%.Then, choosing the medium temperature paraffin-ceresin wax mold material which one contents ceresin wax 50%, paraffin wax 40%, rosin 10% as the new mold material, and choosing the mold material which one have already been used once as the old mold material, studying the mold material with the different proportion of the old and new mold materials. The test results show that, the mold material can meet the needs of investment casting mold material performance in practical production when joining not less than 1/10 new mold material into old mold material. Later, modifying the pattern material by adding one-tenth new one to the old one the last time used, the result is that the comprehensive performance of the pattern material which used after the twenty seven times seriously deteriorated. So that, the pattern material can no longer to recycle, only for recycling.In addition, in order to optimize the forming process of wax pattern, on the basis of the above research, the Moldflow simulation analysis software which was widely used in the field of injection molding is sleeted for simulating the spherical disc wax mold injection molding process, choosing the filling time, filling pressure of the velocity/pressure switch process, volume shrinkage, clamping force, shrink mark index and weld line index as the evaluation standard. At last, the design of gating system of spherical valve is completed.Finally, the process of the filling, holding pressure, cooling of the spherical valve is simulated by the Moldflow simulation analysis software simulated to study the influence of melting temperature, pattern temperature, injection time, holding pressure to the forming quality of spherical valve wax mold. The parameters of injection molding process after optimization are got, that is the wax mold shrinkage rate is minimum when the injection temperature is 55 ℃, injection time is 19s, pattern temperature is 23 ℃, the pressure holding time is 13 s, holding pressure is 90%. These conclusions can provide reference for the optimization of wax mold forming process.