On-screen real-time cost estimating

In the early phase of design the product detail is usually limited, offering general details such as overall size, basic shape and estimated volume. However, it is at this stage that a large proportion of the avoidable costs are typically created, normally between 50 and 70% of the final cost. Due to this the ability of designers to estimate product costs at this stage with more accuracy provides competitive advantage and can avoid some of these in-built costs. This paper describes a methodology of an on-line automated computer system for injection mouldings that enables more accurate cost estimating. The approach adopted enables designers to make informed choices during the design process, not only in terms of functionality, but cost implications in terms of design, materials and, in the case of injection mouldings, complexity. The proposed approach uses a CAD package, in this case IDEAS solid modeling, in which a special set of injection moulding features has been configured for product development. In the proposed approach the designer builds up the product stage by stage (sub-part by sub-part) and, at each addition to the design, parametrics are used to estimate costs using a small number of parameters derived from specific component features and other conceptual design data. This is the Injection Moulding Cost estimating Program. This process will be described in detail within this paper, illustrating the method of product build-up and how avoidable cost increases are identified easily during this process. The approach described provides a concurrent on-screen cost estimate as the product is developed that has been validated to within 20% of the actual cost employing the processing parameters likely to be used.