Simulation Study On Casting Process Of RAM Of Large High-Grade CNC Machine Tools

Ram is one of the key components of the high-grade CNC machinetools, its manufacturing level determing high precision, high-quality andhigh performance of CNC machine tools. It is meanful for us to improvethe ability of independent innovation by achieving high-grade CNCmachine tool design and manufacture of parts independently according tothe program of production-learning-research. In this paper, the rammaterials, structure and process of heavy section castings were analysised,and the reasonable casting processes were designed. then, the castingparameters were optimized by analysis its filling and solidification processcombined with the finite element CAE simulation software ProCAST. Themain conclusions can be conclued as follows.1. The program of vertical, bottom and open casting system waschosen by considering actual production situation and many otherreference materials, the cross-sectional runner areas of stright, horizontal,inner are93cm2,86cm2and75cm2, and the shape of them are circle,trapezoidal and rectangle respectily.2. The mold filling time of numerical simulation is consistent with theproduction time, all are about61s. The filling process is nosmooth andhigh-pressure casting hole layout at the top of the heavy part of the flowappeared agitating is accord with the parts of defects of the actualproduction process.3. The total filling time is not decreasing with the velocity ofinner-gate is increasing due to filling process is nonsmoothly results fromdifferent wall thickness and complex cavity, the velocity will dramaticincreased from the thick section parts to thin section parts as well as liquidmetal was backed by resistance of sand core in the filling prosess.4. The top outlet riser can reduce the resistance of the filling, speed upthe rate of the filling liquid metal to conducive the rapid casting, and feedthe top of casting to remove the porosity and shrinkage defects.5. The phenomen of stirred liquid metal at the top of casting can be eliminated by arranging cold cast irons at the bottom of the casting. At thesame time, the bottom of the casting can be solidificated firstiy. porosityand shrinkage defects can be eliminate by arranging cold cast irons andriser reasonably.