معماری برای ادغام عمودی ملاحظات شکل دهی از طراحی تا برنامه ریزی عملیات

To meet the competitive demands of modern manufacturing, it is necessary to reduce design times and enrich decision making by integrating process planning into the design activity using Concurrent Engineering principles. Although this is traditionally done through the interaction between designers and process planners, it is perhaps more desirable for a CAD system to have the functionality necessary to automatically advise the designer of the shop floor implications of design decisions. Cutting tool selection is an essential thread linking feature-based design of machined parts to process planning. Thus, the implementation of tooling considerations into design is an important requirement for an integrated CAD/CAPP system. This paper defines an architecture to enable the vertical integration of tooling considerations from early design to process planning and scheduling. The architecture is based on a five-level tool selection procedure which is mapped to a time-phased aggregate, management and detailed process planning framework. This paper draws on literature and the results of an industrial survey to identify the tooling methods suitable for integration within a CAD system and categorises them into the five levels of tool selection. The functions are then placed on a time-dependent framework that covers the progression of a product from design to process planning. The new functionality is being implemented as an object-oriented application called VITool, which is being developed so that it can be fully integrated within an existing CAD system.

The organisation of a manufacturing facility of any kind is a highly complex task involving a myriad of different skills. Examples of the different tasks involved include routing, tool selection, set-up analysis, cutter path optimisation, machinability assessment and time and cost estimation. The subject areas and methods that encompass these functions are also wide ranging and include feature technology, artificial intelligence, mathematical modelling and manufacturing philosophies (cellular manufacturing, just in time, agility, etc.) amongst others [1] and [2]. To provide enough time for the decision-making process associated with these tasks, it is desirable to integrate process planning within all the stages of product development from conceptual design through to the introduction of the finished design on to the shop floor. Since many activities within design and process planning have been implemented as computer software in the form of computer-aided design (CAD) and computer-aided process planning (CAPP), it is now becoming feasible to automate process planning tasks as a design takes place and information about the component being designed becomes available. The three key elements required for successful CAD/CAPP integration are [3] 1. A framework for structuring manufacturing information. 2. Procedures for mapping form features to manufacturing considerations. 3. Procedures for utilising available information about components already machined. This paper describes the characteristics of an intelligent design system with embedded process planning functionality within the context of the above key elements. Emphasis will be placed on the following. • The need for an integrated system to carry out process planning in a time-phased manner, such that methods are invoked when the data they need become available. • The importance of tooling issues as a link between design and process planning. • The use of object-oriented methods to enable an integrated system to be implemented as a module of an existing CAD system. As well a carrying out a review of existing research, a limited survey was carried out to establish Industry requirements for intelligent manufacturing. The survey involved 400 companies from various manufacturing sectors (small job-shop firms to large flow manufacturers in various industrial sectors including tool manufacturing, aerospace, shipbuilding and general batch manufacturing) from which 38 useful responses were returned. Interviews with the five collaborating companies involved with the project were also carried out to gain more opinion about the topics covered in the survey. The key findings of this survey are presented in the appendix and are referred to throughout the remainder of this paper.

A limited survey revealed a need within Industry to facilitate Concurrent Engineering practices by integrating process planning functionality into CAD. Since it is desirable that for efficient product and process development, as much process planning should be done as early on in the design as possible, it is necessary to categorise process planning methods within the aggregate, management and detailed (AMD) architecture according to their data requirements and their interfaces with design. Using tooling issues as the link between design and process planning through the integration of the five levels of tool selection within the AMD architecture, a framework for vertical, time-phased CAD/CAPP integration has been developed in the form of nine software modules. These are currently being developed at Durham University under the name of VITool as add-ons for a proprietary suite of computer-aided engineering software. It is envisaged that the result of this research will provide Industry with a tool to assess the impact potential designs might have on the shop floor. This will lead to more efficient product and process development since likely problems will be highlighted during the early stages of design, rather than being discovered prior to, or even during production.