A STUDY OF STEP DATA MODEL SUPPORTING TOLERANCING DATA IN A CAD SYSTEM

• Main Authors: Chang Shao-Yuan, 張韶元
• Other Authors: Tsai Jhy-Cherng
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/90099843136095503010

碩士 === 國立中興大學 === 機械工程學系 === 88 === Tolerancing technology is the foundation of product quality and cost. However geometric dimensioning & tolerancing (GD&T) information and neutral file format are lacking in current CAD systems. As a result tolerancing technology is unable to be carried out by CAD systems. This thesis integrated ISO 10303 STEP (STandard for the Exchange of Product model data) and Computer-Aided Tolerancing Design system to develop a STEP-based GD&T information translation system thus the translated GD&T information becomes a common data format. The subjects of this thesis include GD&T data model standardization, mapping relationship between GD&T standards ASME Y14.5M and STEP-Part 214, mapping relationship between GD&T information of a CAD system and STEP-Part 214, establishment of Standard data access interface (SDAI) and STEP interface of tolerancing. GD&T data model standardization studies how to establish a completely product GD&T information data model system using STEP. The mapping relationship between ASME Y14.5M and STEP-Part 214 investigates the corresponding relationship between tolerancing specifications and STEP-Part 214. The mapping relationship between GD&T information of a CAD system and STEP-Part 214 discusses relationship among GD&T information of a CAD system, data models and tolerancing specifications. Product data models are constructed according to these relationships. The establishment of SDAI discusses the operation of STEP file output by the input and output mechanisms of SDAI defined in ISO 10303. The STEP interface of tolerancing develops a STEP-based interface to translate GD&T information and to process file exchange of a CAD system. Examples describing the usage and operation flow of the developed system are also illustrated.