Study On Skin Model And Tolerance Modeling Of Cutting Part Of Ordinary Lathe Tool

A series of discussions launched by this dissertation, based on the specification requirements of new GPS and other mathematical tools, the specification skin model and the situation variation model are built. Then the tolerance modeling of cutting part of ordinary lathe tool is built to further research.The study on specification skin model begins with introducing the structural models and the expression of a variety of models. Then the relationship between discrete geometry and the specification skin model is analyzed to identify that the constructed object is discrete points set. The intrinsic deviation of the specification skin model divided into two categories:random deviation and system deviation. For the random deviation, trivariate normal distribution is used to simulate the variation of random sampling in three ways. For the system deviation, using quadric surface structure to construct is simple in calculation, it can meet the requirements of specification when the object is planar model. In this dissertation, it integrate random deviation on the basis of the deviation, so it needs to estimate the vertex normal of constructed discrete quadric surface firstly. This dissertation goes on to discuss three cases of vertex normal estimation methods:grid, function and point cloud model. The random deviation is attached to system deviation along each vertex normal axis. On the basis of previous work, the RBF network is adopted to interpolate discrete surface to obtain a continuous specification skin model. Finally tolerance constraints are imposed on the point cloud, makes the generated simulation surface in the tolerance range.The situation deviation of specification skin model and geometric elements and their constraints are the basis of variation model and tolerance model, so the type, relationship and geometric variation of geometric element is discussed. New GPS theory summarized geometric variation into seven basic classes of invariable, other complex classes can be derived from seven basic classes of invariable. The self-referenced geometric variation cross-referenced geometric variation and mating geometric variation form a complete set of situation relations between geometric elements. Based on lathe tool structure and the knowledge of the rigid body kinematics, this dissertation puts forward a method for constructing variation model of lathe tool in matlab, this method can be summarized to "Two Process" and "One Treatment". One of "Two Process" is transformation process, which imposes on the plane. The other is geometric elements boolean operation process, which construct the close geometry."One Treatment" is parameterization of the previous two processes, which controls the model with variabls.The inclination tolerance instead of angle tolerance is used to tolerance modeling for cutting part of lathe tool, the control of tolerance model involves the the datum, the degrees of freedom theory and SDT variable. Take flank as an example, the inequalities of SDT variables and its tolerance of flank constitute the deviation domain. Basic, three deviation domains of lathe tool may form a comprehensive tolerance domain, which can use for further optimized design according to functional requirements and economic indicators.