Cost Considerations

A major consideration in the management of production is to understand the cost impact of various designs. Much of the work relating to overall production management including the design of facilities would seem to indicate that the decision processes are serial rather than concurrent or iterative feedback. The classical idea would appear to be that the engineering designers decide on the layout of the line with primary interest in the engineering performance measures of the stations and subsequently this design is costed and justified on some concept closely related to discounted cash flow. There are a number of papers discussing the inadequacy of the approach just outlined, particularly in relation to systems with inherent flexibility and the justification of which may be more strategic rather than tactical. An appropriate philosophy for world-class companies is for the company to re-invent itself from time to time. This is in contrast to the view that a company can retain its competitive advantage by simply being effective in existing markets. Although it is important to retain or improve one’s position in existing markets, it is often in the development of new markets, new customers and new products or services that the health of the company is ensured. Re-invention therefore is a questioning philosophy of how the company can do better today and what it should be doing tomorrow. Clearly, it is a mixture of continuous improvement in all aspects of its activities and new product development. Thus, manufacturing strategy should support marketing strategy and give competitive advantage to the organization. In the light of this strategic trust, investments in production facilities should be carefully assessed from the point of view, of quality, flexibility, time-to-market, dependability, market positioning as well as cost. It is of course difficult to put all these diverse tangible and intangible benefits into one overall metric with the view to choosing particular marketing and manufacturing strategies including production systems designs. From the decision theory point of view what is involved is a multiple-criteria decision problem. However, the authors are unaware of any published work which applies techniques of multiple-criteria decision making such as ranking/scaling methods, analytical hierarchical processes to the selection, at a strategic level of a particular production system. There is an obvious need to reconcile the point of view of the economists, who would be concerned with opportunity costs, and the approach of accountants who are generally more interested in using actual historical or projected tangible costs, with the imperatives of manufacturing engineering and the operating philosophies and desires of production management, perhaps through a process of brainstorming and Delphi methods. Arising out of the strategic analysis, outline and broadly based decisions on the required manufacturing facilities and capabilities of the company would be developed. For example, decisions might be made to invest in automation to develop flexible manufacturing systems (FMS) or to use production lines. At a level below the strategic level, tactical level decisions must be undertaken to specify, for example, location, size and general layout of manufacturing facility, production machine processes, efficiency/effectiveness, required throughput, capital cost targets, quality targets, degree of flexibility envisaged and operating cost targets for each of the manufacturing systems specified in outline form at the strategic level. Finally, it is at the detailed design level that the production line, if one is required, is completely specified with regard to the number of stations, the equipment at each station, the number of operatives at each station, the inter-station buffer capacities and the work-load allocation to achieve the required throughput. Issues related to maintenance and reliability of equipment need to be considered. The overall objective is to meet the target cost per unit produced. The focus of this book is at this detailed design level.