The Product Data Technology Advisory Group, short PDTAG, was established on 30 September 1992 under the auspices of the ESPRIT CIME Division of the Directorate General XIII of the European Commission. Its goals include promoting European cooperation and improving the European infrastructure in Product Data Technology, particularly in connection with the new standard STEP (ISO 10303). The dissemination of information on Product Data Technology and on European contributions to STEP is of crucial importance to this development. The current volume is the first title in a new PDTAG subseries to Springer Publishers' Research Reports ESPRIT. This new subseries intends to form a comprehensive repository of publications on Product Data Technology resulting from ESPRIT Projects and from European contributions to standardisation based on ISO/STEP. PDTAG welcomes the opportunity to make this information more accessible under the format of a coherent subseries within the established framework of Research Reports ESPRIT. Much valuable background on the new international PDT standard can thus be found in the same collection.
This monograph presents a new generalization of utility theory, fuzzy rationality. It is a group of techniques that can be applied in different stages of decision analysis – problem modeling, measuring preferences and uncertainty, and the analysis of risk attitude. A common feature of all these techniques is the ability to measure the actual opinion of the decision maker. At a later stage, the subjective information is analyzed in order to identify the best alternative according to the real, fuzzy rational decision maker.
Principal authors: U. Kroszynski, B. Palstr9Sm 1.1 The evolution of concepts and specifications for CAD data exchange The CAD/CAM community has witnessed, during the last decade, the appearance of several specifications as well as proposals for standards which either attempt to cover wider areas or to be more reliable and stable than the others. With the rapid evolution of both hardware and software, the capabilities offered by CAD systems and CAD based application systems are far more advanced than they were only ten years ago, even when they are now based on micro-computers or personal comput ers. The situation with standards, however, is not and cannot be so. In order to be reliable and accepted by a wide community of both vendors and users, a standard has to be sta ble. This implies a life span of at least a decade. This also implies that the standard has to be general and flexible enough to accommodate present as well as expected future developments. 1.1.1 IGES The initial development of concepts for CAD data exchange is strongly influenced by the US Integrated Computer Aided Manufacturing (ICAM) programme, that dealt with the development of methods for data exchange. In September 1979, a subgroup was estab lished with participation of the National Bureau of Standards, the General Electric Com pany, and the Boeing Company. The result of this effort was the Initial Graphics Exchange Specification (IGES) that was published as a NBS report [61] in 1980.
Modern CAD systems generate feature-based product shape models with parameterization and constraints. Until recently, standards for CAD data exchange among different CAD systems were restricted to the exchange of pure shape information. These standards ignored the parameters, constraints, features, and other elements of ? design intent? present in the model to be transferred. This paper suggests an implementational foundation for CAD data exchange with parametric information for the preservation of design intent, based on the use of newly published parts of the International Standard ISO 10303, which is informally known as STEP ? STandard for Exchange of Product model data. A case study is presented, which employs a hypothetical STEP application protocol (AP) using Parts 55, 108 and 111 of ISO 10303. A prototype translator based on this AP has been implemented and tested. The paper reports on the experience gained in parametric data exchange.
Author: Europäische Gemeinschaften Europäisches Strategisches Programm für Forschung und Entwicklung auf dem Gebiet der Informationstechnologie Subprogramme Computer Integrated Manufacture (CIM)
ESPRIT Project 322, "CAD Interfaces", has been established to define the most important interfaces in CAD/CAM systems for data exchange, data base, finite element analysis, experimental analysis, and advanced modeling. The definitions of these interfaces are being elaborated in harmony with international standardization efforts in this field. One principal goal of the project is to develop techniques for the exchange of CAD information between CAD systems, and from the CAD domain to CAA (Computer Aided Analysis) and CAM (Computer Aided Manufacturing). This volume presents a proposal for a neutral file format for CAD data: curves, surfaces, and solids. The specification is based on a reference schema for CAD data bases and is defined informally with respect to its semantics and formally with respect to its syntax. This volume is a revised edition of "Specification of a CAD*I Neutral File for Solids" Version 3.2. The revision reflects the enhancements which result from the implementation of communication processors in eight different CAD systems and from the practical exchange of solid models between these systems. Due to the close interaction between the CAD*I project and the coming-up international standard STEP this specification also serves as an introduction to the geometry model that will be included in the future international standard.
Many enterprises try to integrate product design, process planning, and manufacturing efficiently using systems based on computer-aided technologies (CAx), so that they, though maybe geographically separated, are able to collaborate with each other using the Internet. However, due to the lack of a standardlized form of data format, data exchange between CAx systems is still a critical research area. Data exchange between two computer-aided design (CAD) systems and data transferring from a CAD system to a computer-aided process planning (CAPP)/computer-aided manufacturing (CAM) system have been partially achieved through neutral files such as STandard for the Exchange of Product model data (STEP) or Initial Graphics Exchange Standard (IGES). However, no practical mechanism for data exchange between two CAM systems currently exists, and this gap in knowledge is the focus of this research. A CAM system contains two broad types of data: manufacturing information and geometry information. Manufacturing information contains parameters regards in the machining operations, including feed-rate, spindle speed and tooling data, etc., whereas geometry information is a machining feature that specifies the volume to be removed. It is not possible to use STEP or other currently used neutral file formats to represent or exchange CAM data because they only focus on the geometric information in a CAD system. STEP-compliant numerical control (STEP-NC) is the data model for the new generation of NC machining and it records both manufacturing information and geometry information in its machining-related entities. Therefore, this research considers and utilizes STEP-NC for CAM-CAM data exchange. The aim of this research is to investigate a method using STEP-NC as the neutral file format to realize data exchange between CAM systems. More specifically, this research enables two processes: (1) extracting information from a CAM system to populate a STEP-NC file; and (2) extracting information from a STEP-NC file to populate a model in a CAM system. Creo Parametric 2.0 is used as the CAM system and a plug-in named "CAM Data Exchanger" has been developed. The CAM Data Exchanger has two components: the Creo Parametric Data Processor and the STEP-NC Data Processor. The Creo Parametric Data Processor was developed using Visual Studio 2010.NET platform and was coded in C++. This component extracts data from Creo Parametric and populates data into the CAM system. The STEP-NC Data Processor was developed on the same platform but coded in C#. The STEP-NC Data Processor can read and write a STEP-NC Part 21 file. As a result, the CAM Data Exchanger is capable of exchanging data for some typical Creo Parametric features, e.g. workcell, NC-sequence, and design features. As the main entities encapsulating information in the CAM system, Creo Parametric features play an essential role and therefore they are focused in this research. Each of the Creo Parametric features should have a standardized STEP-NC entity as its counterpart. This research analyses and compares the data structures of some Creo Parametric features and the corresponding STEP-NC entities. Based on this analysis, the bi-directional mapping between the Creo Parametric features and the STEP-NC entities is established, which enables the CAM system to exchange data using a STEP-NC neutral file. The main contribution of the research is that it proposes a mechanism for data exchange between CAM tools and demonstrates the system development process via a Creo-based pilot.
