发动机缸体多工序加工变形误差传递的建模与分析

Modeling and Analyzing for Stream of Variations in Multistage Manufacturing Processes of Cylinder Block

定义了发动机缸体多工序加工过程(MMP)中涉及的4类坐标系,分析了基准误差、夹具误差和刀具误差等误差源在多工序之间的传递、耦合关系.采用有限元法对发动机缸体加工过程中由于切削力引起的变形进行仿真分析,将被加工表面的变形量与刀具误差进行耦合;利用多个特征点的微分运动矢量(DMV)来表征一个尺寸特征,对单点DMV误差流(SoV)的状态空间模型进行扩展,建立了基于点集DMV描述、考虑切削力所致变形的SoV模型.同时,通过B12型发动机缸体加工过程中的实测数据对理论模型进行验证.结果表明,所建立的变形SoV模型具有较好的实用性和有效性.

Four types of coordinate systemsare defined for the multistage manufacturing process （MMP） of cylinder blocks. The coupling relationships between datum error, fixture error and tool error areanalyzed. Through the finite element analysis of the cylinder block manufacturing process, the cutting force-induced deformation displacements of the processed surface are simulated with tool error. The specific characteris- tic dimension is described by using differential motion vectors （DMV） of multiple feature-points. The state space model of the stream of variations （SoV） based on the DMV of a single point is extended based on the DMV description by considering the cutting force-induced deformation displacements. The effectiveness and feasibility of the model are validated by a case study of the B12 cylinder block.