Research On Process Model Construction Based On MBD And Manufacturing Feature Constraint Relationship

The MBD technology has been developed as the core technology for manufacturing to realize 3D digital design and manufacturing,and the application of process model based on MBD is the inevitable trend of 3D digital process design.It is the decisive factor to acquire and mine effectively a large amount of process and associated information for transfering MBD information to process model standardization.For the lack of nongeometric constraint relationship in the current construction process model,a method of process model construction based on MBD and manufacturing feature constraint relationship is proposed in this thesis.The constraint relationship considers both geometric and non-geometric constraint information,aiming to realize precise constraints on the association between manufacturing features,and a series of process routes are optimized.Finally,the process models are generated to ensure product accuracy and quality with high degree of automation.The main contents are as follows:The information of MBD model is visualized as the feature geometric and nongeometric information that constitutes the manufacturing features.The manufacturing feature is defined and classified,and the method of identifying and extracting the process constraint attributes between manufacturing features is studied as the data support for the establishment of the process model.Research on constraint relationship of manufacturing feature based on node importance.The attributes of topological relationship and dimensional constraints between manufacturing features are studied to realize precise constraints on the association between manufacturing features.Firstly,the adjacency matrix of semantic constraint is established with the 3D positioning dimension between the feature,in which the underlying reference relationship,positioning constraint and geometric tolerance are mined,and the manufacturing feature constraint connected graph is constructed.Secondly,technological dimension chains of multi-dimensional are aggregated and analyzed based on the constraint connected graph of manufacturing feature,and a complete feature dimension chain connection model is constructed.Finally,the initial feature processing order is obtained,the number of topological relationships between feature nodes is extracted,the connection model of feature dimension chain is improved,and the primary and secondary association of features is combined,and the node importance is solved by the node importance theory of complex network.Finally,by extracting the number of topological relationships between feature nodes,perfecting the connection model of feature dimension chain and combining the primary and secondary relevance of features,the node importance is solved by using the node importance theory of complex network,and the initial feature processing order is obtained.Based on determining the component elements of machining elements,a multi-objective optimization model of machining resources is established for the problem of process route planning.An optimization method of process is proposed to solve the machining element sequencing based on bacterial foraging and ant colony algorithm with the minimum conversion rate of processing resources,so that the intermediate process model set of the process model is built.Based on the above theory,the prototype system of 3D process model is designed and developed by UG secondary development technology.The system supports the functions of acquisiting information for constraint relationship between manufacturing feature,determinating and optimizating the sequence of machining elements,and generating the final process model.The effectiveness and feasibility of the research method and the function of the system are verified by the typical parts with different complexit.