Xionghui Zhou

A feasible approach to the integration of CAD and CAPP

Although current CAD systems are declared to be feature-based, in fact, the so-called feature is just a modeling macro or menu name such as Protrusion, Revolution, Cutout, Block, etc., instead of a design feature or manufacturing feature in accordance with engineering practice. Consequently, product model data insufficiency and incompatibility between varieties of application systems are still the major barriers to system integration, especially the integration of design and process planning. This paper proposes a practical solution for a bi-directional integration of CAD and CAPP on the platform of commercial CAD systems. The key techniques such as feature recognition and conversion, feature parameter and constraint extraction, feature tree reconstruction, technical information processing, process planning, automatic process drawing marking and 3D material stock CAD model generating are discussed. And the extracted features and their related technical information and knowledge are encapsulated together with the geometry-oriented CAD model to form an integrated product information model to facilitate effective integration with the downstream activities. The integrated CAD/CAPP system is implemented on a commercial CAD package, UGS/SolidEdge. A case study and industry implementation illustrate the feasibility of the approach proposed.

A geometric reasoning approach to hierarchical representation for B-rep model retrieval

3D solid model similarity is dependency of many intelligent design applications, such as design reuse, part management, case-based reasoning, and cost estimation. Matching and comparing its intrinsic boundary representation (B-rep) is a critical issue to retrieval. In this paper, we proposed a geometric reasoning approach to generate hierarchy for B-rep model retrieval. We extracted the winged-edge data structure to support series algorithms for underlying geometric reasoning, which is mainly composed of 3 steps to build hierarchy: partitioning, assembling and simplifying. This hierarchical representation is featured with level of detail ( L O D ) retaining geometric and topological information which is proved to be efficient in both global and partial retrieval. Our approach is based on the standard for the exchange of product information ( S T E P ) , which is suitable for data exchange between heterogeneous CAD systems. The result of case studies from prototype implementation demonstrates its effectiveness and efficiency. Hierarchy of B-rep model is generated by geometric reasoning automatically.This shape descriptor eases global and partial retrieval at level of detail.Interactive prototype system gives why and how similar features are matched.

Computer-aided checking fixture design system for automobile parts

Checking fixture design is a complicated task requiring a strong professional background and rich practical experience. In order to enhance design efficiency and quality, this paper proposes a computer-aided checking fixture design methodology. The key issues include a new minimal volume bounding box generation approach for workbench design, a multi-objective optimisation algorithm of locator layout for location design, a multi-surface extension and transition method for checking components design and a flexible part library system to reuse standard parts and to assemble them automatically. As an implementation of the system based on the key methods, Checking Fixture Design Wizard for automobile parts, a plug-in on CAD software, is developed. Finally, a car door checking fixture design is taken as a case study to verify its feasibility and practicability.

Hierarchical representation and similarity assessment for reuse of sheet metal parts

Sheet metal parts are widely used in the manufacturing industry. With the number of 3D models increasing, it is essential to retrieve existing resources. Effective similarity assessment would be useful in many downstream applications, such as design reuse and manufacture process revision. We propose a hierarchical representation and similarity assessment algorithm to retrieve 3D models of sheet metal parts. Based on single-side representation extracted from solid models, flat and bent faces are recognized and clustered into groups. The morphological relationship between these two groups is then described and an attributed graph is built to store the connection between flat groups. A hierarchical representation is derived by a simplification and assembly process. This structure supports similarity assessment in different levels of detail; thus, a multiple-resolution formula is introduced to measure the total similarity. The algorithms were implemented based on a neutral standard for the exchange of product model data (STEP) format and a prototype demonstrates the application in shape search and reuse in manufacturing industry.

Similarity Assessment of Mechanical Parts Based on Integrated Product Information Model

To improve the quality of design, reduce the cost of production, and shorten the cycle of product development, an effective system to manage and reuse existing design resources is established. A novel two-step algorithm based on integrated product information model is put forward to analyze the reusability of design resources. First, the global shape ignoring the interior details is compared with check if they belong to the same category. Then, the detailed feature shape is compared with catch, the exact reusable design resources. Finally, a case study proves that the proposed method has higher accuracy.

Service oriented cross-platform framework for 3D part library based on diversiform knowledge implantation

ABSTRACTRecent years have seen the great advancement in rapid design and manufacture. As a primary foundation, part libraries play an important role in machine and mold design. Most current libraries are created in specific use environments or CAD platform, which will bring obstacles in the share and exchange of part information. In this paper, we proposed a service oriented cross-platform framework for 3D part library, in which the parts in the library are created in a native ACIS modeler, and then the models are converted into CAD files with various formats, finally these files can be imported into CAD platform for practical design. The whole framework can be divided into three parts, namely, PLS(Part Library Service) provider, PLS adapter and PLS host. Through different adapters, the PLS can be easily grafted on most mainstream applications as a plug-in subsystem or even deployed on the website. In the detailed implementation, diversiform knowledge for part parameter and design is implanted to automati...

Research on Feature-Based Data Exchange Between Tribon and UG

For shipbuilding and auto industry, using different CAD platform to fulfill one project is very popular. Engineers have to deal with so many data exchange works. While the main problem is that many raw modeling features have been lost during this process and could not be inherited by another system. So from this point of view, how to realize the modeling data exchange or called geometry data seamless integration between heterogeneous CAD systems is very important. In this paper, we propose a new method to realize such function. We trace ship hull modeling history in Tribon and then via the XML neutral file, a same 3d model will be regenerated in another system UG. The experiments show that this data exchange method is fairly high efficiency and all modeling features have been inherited. This method can also be widely used in other feature-based CAD platforms such as Solidworks, CADDS5 and CATIA.