CAD Feature Modeling Based On STEP-NC

STEP standard has been used to realize the integration of CAD and CAM as a uniform data model since 1980s. Based on STEP standard, a new interface for CNC programming, STEP-NC, was created, which was capable of carrying out various intelligent tasks. This new CNC standard provides a foundation and development to realize a close relationship between the design and manufacture.CAD feature modeling based on STEP-NC is faced to manufacture. And the information models of features are founded on the STEP-NC standard. There are three innovations in this system:(1) Make STEP-NC as the foundation. By extending the data model and following the principle and methodology of STEP-NC, we create a CAD feature modeling system based on the ISO 10303-224 and ISO 14649-10/11.(2) Feature model is faced to manufacture. The manufacturing feature is different to traditional design feature. It is a negative feature as the cut materials in one workstep. Then these manufacturing features and technical information, such as machining methods, become closer and can be used in the CAPP and CAM directly. Forthermore, we build basic feature gallery, create user interface of UDF, and set up a feature management system to manage the feature gallery.(3) The idea of this feature modeling system is based on the manufacture process. We make CAD feature modeling process as close to manufacture process as possible. So as same as manufacturing, the finished model was obtained after cutting step by step.The first step of modeling is to choose roughcast. Then get the finished workpiece model by inserting of the features needed.On the other side, there are not only the information about figure features, but also information about manufacture and other assistants. These semantic informations can be used in high-level directly. A system of CAD feature modeling based on STEP-NC was built, therefore, the integration between CAD and CAM is realized. And it explores an effective approach to informatization, integration and automatization...