Study In Quality Assurance System Of Rotor Bob-Weight Part Of Helicopter

Rotor bob-weight part is one of the most important parts of helicopter, which requires strict precision of the shape bend, surface quality, chemical composition, mechanical properties, and weight warp be controlled in a mini confine. For such a high requirement, the quality assurance system should be complex and especially important. In this article, mold design, chemical composition, melting technics, casting technics, defects predicting, and numerical simulation of casting solidification were analysed in detail. Eventually, a comprehensive quality assurance system is formed to assure the quality of part by controlling every key step and important technical standard strictly. For iron has low coefficient of thermal expanding and high heat fatigue capability,we choose it to produce metal mold machined in numerical controlling machine tools. That is useful to ensure surface quality, size precision and high density of the part. The zinc lost in smelting is obviously decreased by controlling mix proportion and melting technics, which ensure that chemical composition and weight of the part fit the desire. By using metal mold casting, we can control mold temperature, infusing temperature, infusing speed to avoid defects of pore, cold partition, shrink and loose. The other important method is using computer simulation technology to predict casting course, test feasibility of casting technics and optimize the process. This paper uses UG 3D software and Magma of Germany as simulation tool in the casting process. Temperature field and casting defects were predicted in casting process. And time of die sinking is also determined as 6 min. There is no defects of shrink and loose under given circumstance.