Analyzed the issues of stability of workpiece during clamping and machining. Discussed classification of the stability problem according to the forces acting on the part in the commonly used machining processes; gave ...Analyzed the issues of stability of workpiece during clamping and machining. Discussed classification of the stability problem according to the forces acting on the part in the commonly used machining processes; gave the methods of calculating clamping force and measures to guarantee the stability of workpiece in the feature-based fixture planning design system.展开更多
Fixture planning is a crucial problem in the field of fixture design. In this paper, the research scope and research methods of the computer aided fixture planning are presented. Based on positioning principles of typ...Fixture planning is a crucial problem in the field of fixture design. In this paper, the research scope and research methods of the computer aided fixture planning are presented. Based on positioning principles of typical workparts, an ANN algorithm, namely Hopfield algorithm, is adopted for the automatic fixture planning. Also, this paper leads a deep research into the selection of positioning and clamping surfaces (or points) on workparts using positioning clamping surface selecting rules and matrix evaluation of deterministic workpart positioning. In the end of this paper, the methods to select positioning and clamping elements from database and the layout algorithm to assemble the selected fixture elements into a tangible fixture are developed.展开更多
The deepth and width of CAD application in coal mining equipments need promote furtherly. The information stream method is applied as the main clue to deal with the related technology and problems in research of manuf...The deepth and width of CAD application in coal mining equipments need promote furtherly. The information stream method is applied as the main clue to deal with the related technology and problems in research of manufacturing tools (Fixtures) planning for AFC (mining scraper bars conveyor) using CAD technique.展开更多
This paper proposes a new machining method for part s using group technology suitable for workshop condition in China. The method divi des the parts of each product into similar kinds according to their features, an d...This paper proposes a new machining method for part s using group technology suitable for workshop condition in China. The method divi des the parts of each product into similar kinds according to their features, an d installs each kind of parts on different working platforms. The working platfo rm, as a unit, is designed to be flexible and is interchangeable. It can be hung and fitted to the CNC working table. By changing the platforms in turn, nearly all the parts of one product can be processed with one CNC machine, and can be s ent directly to an assembly shop. Thus the number of management links is reduced and the production rate is increased. Several working platforms may be needed w hen several different types of parts are being processed. However, to reduce pro duction costs, it is necessary to limit the similarity coefficient of part class ification. The feature-coding classification is better for processing parts wit h this method. A practical classification code made by the author is for plastic injection machines. As an example, ten numbers (0～9) are used to express the d i fferent functions and the main features of the parts in the first code-rank. An insufficient classification may be offset by applying cut store and adjusting f unctions to the processing program in the CNC machine center, thereby allowing a set of parts which are not completely similar to be processed on a single worki ng platform. Before a set of parts with incompletely similar features is machine d on a working platform, it is necessary to plan reasonable technological proces s, for which we adopted an optimum method aimed to shorten the working period so as to increase production rate. The fixture planning for this processing method is also discussed in this paper. Modular fixture is recommended for mounting a set of parts on a working platform. In general, modular fixture has a basic boar d and a set of disassemble locating and clamping elements. Because the working p latform can be used directly as the main locating datum, it is unnecessary to de sign another basic board. However, if a working platform is to be used for diffe rent sets of parts, it is better to design it as a dowel-pin series basic board .展开更多
文摘Analyzed the issues of stability of workpiece during clamping and machining. Discussed classification of the stability problem according to the forces acting on the part in the commonly used machining processes; gave the methods of calculating clamping force and measures to guarantee the stability of workpiece in the feature-based fixture planning design system.
文摘Fixture planning is a crucial problem in the field of fixture design. In this paper, the research scope and research methods of the computer aided fixture planning are presented. Based on positioning principles of typical workparts, an ANN algorithm, namely Hopfield algorithm, is adopted for the automatic fixture planning. Also, this paper leads a deep research into the selection of positioning and clamping surfaces (or points) on workparts using positioning clamping surface selecting rules and matrix evaluation of deterministic workpart positioning. In the end of this paper, the methods to select positioning and clamping elements from database and the layout algorithm to assemble the selected fixture elements into a tangible fixture are developed.
文摘The deepth and width of CAD application in coal mining equipments need promote furtherly. The information stream method is applied as the main clue to deal with the related technology and problems in research of manufacturing tools (Fixtures) planning for AFC (mining scraper bars conveyor) using CAD technique.
文摘This paper proposes a new machining method for part s using group technology suitable for workshop condition in China. The method divi des the parts of each product into similar kinds according to their features, an d installs each kind of parts on different working platforms. The working platfo rm, as a unit, is designed to be flexible and is interchangeable. It can be hung and fitted to the CNC working table. By changing the platforms in turn, nearly all the parts of one product can be processed with one CNC machine, and can be s ent directly to an assembly shop. Thus the number of management links is reduced and the production rate is increased. Several working platforms may be needed w hen several different types of parts are being processed. However, to reduce pro duction costs, it is necessary to limit the similarity coefficient of part class ification. The feature-coding classification is better for processing parts wit h this method. A practical classification code made by the author is for plastic injection machines. As an example, ten numbers (0～9) are used to express the d i fferent functions and the main features of the parts in the first code-rank. An insufficient classification may be offset by applying cut store and adjusting f unctions to the processing program in the CNC machine center, thereby allowing a set of parts which are not completely similar to be processed on a single worki ng platform. Before a set of parts with incompletely similar features is machine d on a working platform, it is necessary to plan reasonable technological proces s, for which we adopted an optimum method aimed to shorten the working period so as to increase production rate. The fixture planning for this processing method is also discussed in this paper. Modular fixture is recommended for mounting a set of parts on a working platform. In general, modular fixture has a basic boar d and a set of disassemble locating and clamping elements. Because the working p latform can be used directly as the main locating datum, it is unnecessary to de sign another basic board. However, if a working platform is to be used for diffe rent sets of parts, it is better to design it as a dowel-pin series basic board .
