طراحی و برنامه ریزی محیط یکپارچه برای جوشکاری: قسمت 2: برنامه ریزی عملیات
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|27234||2000||6 صفحه PDF||سفارش دهید||2679 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Journal of Materials Processing Technology, Volume 107, Issues 1–3, 22 November 2000, Pages 9–14
This paper describes the specification and implementation of aggregate process planning methods for complex welding operations. The methods are implemented as an aggregate process planning tool, CAPABLE/Welding, which can be used to evaluate the manufacturability of complex fabrications at the early stages of design. The first part of the paper discussed the aggregate product modelling methods, which are object-oriented and feature-based. The aggregate product model provides the necessary abstraction of design data to facilitate the assessment of early designs. A key planning requirement was to utilise the aggregate product model by developing process knowledge capturing and optimisation techniques so that production time and cost can be calculated for complex fabrications requiring many welding operations and set-ups. CAPABLE/Welding is a tool usable directly by designers, as it does not require specialist process knowledge. A range of generic welding process models has been developed and the planning techniques are instantiated with regard to company specific production equipment and factory layout. Alternative process and machine options are explored and the optimum production method is found using a simulated annealing algorithm. This selects process types, equipment, finds the best welding orientation, number of set-ups and finds the optimum processes and routes for minimum product cost or lead time. The resulting plans are presented graphically via a hypertext browser. This combines a graphic display of process time and cost distribution by feature with links to the relevant process knowledge. The process planning procedure of a product is used in this paper to illustrate the system functionality.
Extensive research in Concurrent Engineering and DFM (design for manufacture) has focused on the development of computer systems, which can support manufacturability and production cost assessment during the design process . For complex applications such as mechanical design, process planning based approaches are widely used to estimate the manufacturing time and production cost ,  and . Compared with other manufacturability assessment methods, such methods have many advantages such as the flexibility to deal with the frequently changing product data, the capability to handle the interaction among manufacturing factors and a reasonable accuracy in cost and time calculation . CAPABLE is an aggregate process planning tool-kit for integrated product development in concurrent engineering environment, including functionality for machining  and welded fabrications . CAPABLE/Welding is an aggregate process planning system, which can be used to evaluate the design of sheet-metal fabrications at early design stages . CAPABLE/Welding has been developed by the Design and Manufacturing Group of Durham University, UK by a research project funded by the Engineering and Physical Sciences Research Council of the UK. The first part of the paper discussed the object-oriented and feature-based product model of this system. The aggregate product model provides the necessary abstraction of design information for design assessment in the early design stages. This part of the paper discusses the implementation of aggregate process planning methods and their use in evaluation of alternative design options in terms of production time and cost. Calculation of production times and costs typically requires a process plan. For welding processes, producing such a process plan includes optimisation procedures in selecting: welding processes; welding equipment; consumables (e.g. type of electrodes); suitable materials and process parameters. All of these tasks require specialist knowledge, which is the domain of manufacturing engineers. Within a concurrent engineering team, this requires that such experts be on hand at all times during the design process to allow evaluation of manufacturability issues. CAPABLE/Welding is intended to support this requirement by providing an automated analysis that does not require intervention by the process expert for each design modification. This is achieved by using a process knowledge base to generate and assess process options from information in the product model and the factory layout model. This knowledge should be controlled by the company process planning experts and linked to an up-to-date factory database. The mode of operation is for designers working on a CAD system to intermittently submit their current design model to CAPABLE/Welding via an extension to the CAD system. The analysis would run as a background task and return both a quantitative analysis of cost implications of each design feature and details of the selected process that would inform further design refinements. This prototype system developed uses an X-Windows interface for input and a hypertext browser for results.
نتیجه گیری انگلیسی
The functionality of an aggregate process planning system, CAPABLE/Welding, has been described in this paper. This system can be used in the early stages of the design process to estimate the production cost and lead-time of a welded fabrication. A simulated annealing algorithm is used to select optimal fabrication processes and equipment. By using the process knowledge base and the SA program, the system can produce results efficiently and with acceptable levels of accuracy. Future work will include a multi-objective optimisation program such that the user can have the flexibility to choose a desirable set of solutions from several possible routing options generated for a particular factory.