چارچوبی برای گسترش برنامه ریزی فرایند به کمک کامپیوتر شامل فعالیت های کسب و کار و بازیابی داده ها طراحی و ساخت به کمک کامپیوتر (CAD / CAM)

Computer aided process planning (CAPP) systems have had limited success in integrating business functions and product manufacturing due to the inaccessibility and incompatibility of information residing in proprietary software. While large companies have developed or purchased complex order management and engineering applications, smaller manufacturers continue to use semi-automated and manual methods for managing information throughout the lifecycle of each new product and component. There is a need for reconfigurable and reprogrammable systems that combine advances in computer aided design (CAD/Computer Aided Manufacturing (CAM) technology and intelligent machining with product data management for documentation and cost control. The goal of this research is to demonstrate an architecture in which customer service, CAPP and a costing methodology known as activity based costing (ABC) are incorporated into a single system, thereby allowing companies to monitor and study how expenditures are incurred and which resources are being used by each job. The material presented in this paper is the result of a two year university and industry sponsored research project in which professors and students at the Costa Rica Institute of Technology developed a software application for FEMA Industrial S.A., a local machining and fabrication shop with sixty five employees and both conventional and CNC capabilities. The final results represent not only a significant contribution to local industry and to the students’ education but, also to the continuing growth of CAPP. Implementing better decision making tools and standardizing transactions in digital format would reduce the workload on critical personnel and archive valuable knowledge for analyzing company methods and expertise.

The Costa Rica Institute of Technology (ITCR) is very conscious of its role and responsibility in contributing to the growth and modernization of the national manufacturing industry. Companies are constantly looking for new tools to optimize the use of their resources and to remove the divisions which exist between administration, engineering and production on the shop floor. While many years of experience in component and assembly fabrication have provided engineers and machinists with extensive knowledge related to processes and machines, companies continue to struggle in the areas of automation, information management and computerized design and planning techniques. The goal of this research is to develop a software framework that demonstrates how computer aided design (CAD)/computer aided process planning (CAPP)/computer aided manufacturing (CAM) technology can be combined with costing and business tools and made available to small and medium sized firms. There are various well documented approaches that integrate cost analysis with CAPP. The first involves providing immediate feedback to designers as they work so that the economic implications of their decisions are understood at the earliest possible time and unnecessary costs can be avoided [1]. The second utilizes methods focused on optimizing process plans on the basis of time or cost or on some weighted combination of the two. Tool selection, process selection, tool path design, process parameter selection and operation sequencing are the most common areas for optimization in process planning. Mathematical methods such branch-and-bound for tool selection, dynamic programming for parameter selection and genetic algorithms for operation sequencing are among the examples [2]. This research proposes an activity based costing (ABC) methodology which does not optimize the process plan but, instead provides a tool for identifying the origin of each cost associated with designing, engineering and fabricating a part using company resources. ABC has proven to be very effective in product manufacturing and where automated processes are prevalent. The proposed system utilizes a Visual Basic 6 (VB6) interface that ties together customer service, process planning, a commercial 3D CAD solid modeling system, a CAM system that has built in CAPP and various business functions such as databases and document generation. This unique approach also addresses the complex problem of retrieving design and manufacturing data, critical to the overall cost of the part, using commands from the CAD/CAM Application Programming Interface (API) library of functions. Fig. 1 outlines the specific areas of work related to the research presented in this paper. Phase one consisted of identifying the level of soft automation and CAD/CAM/CAE system usage in the local industry, specifically at component and assembly manufacturers who use CNC equipment. An evaluation of questionnaires and interviews led to the selection of a company that met the criteria of having the personnel, software capabilities and infrastructure necessary for developing a working program and a corporate vision toward automated manufacturing. A team from the university was composed of professors and students with multidisciplinary skills and backgrounds such as design and manufacturing, cost analysis and computer programming. A detailed analysis of company operations and interviews were used to determine the flow of information and specific software functionality. Program design and development, testing, presentations to representatives and documentation completed the project. Full-size image (41 K) Fig. 1. Areas related to research development.

Continued advances in CAPP and CAD/CAM technology are constantly creating opportunities to reach more advanced levels of integration between administration, engineering and shop floor production. This paper lays the foundation for further work in API programming to retrieve data critical for accurate handling of customer orders and more efficient distribution of information between departments. The important contributions of this research on are: (1) it presents an architecture for a CAPP system with an integrated costing tool for evaluating company performance and providing valuable feedback to planners and management personnel, (2) it combines developed and commercial software, including independent CAD and CAM systems, in an framework that can be expanded and modified to meet company requirements and (3) it utilizes a single user interface to combine both administrative and engineering tasks. The results from this project received praise from local manufacturers and were published in both university and local newspapers [21]. Other companies that viewed the software also expressed the need that exists for soft automation tools that bring administration and engineering together. An important key to the success of this project, aside from the team effort and the motivation exhibited by the students, was the pre-existing relationship which existed between the author and the owners of the machine shop. Other projects to implement CNC and resolve machine code format and communications problems had already been completed. This resulted in a confidence to share real information and openness between the university participants and the shop management, allowing the system to reflect day to day operations.