Human cognition as an intelligent decision support system for plastic products’ design

Abstract

Engineering work is a complex task mainly supported by computer aids. This paper highlights its deficiencies when the designer cannot obtain any expert recommendations or guidelines from the computer’s program regarding a decision-making process such as material selection. Particular product’s development design process, within a well-known enterprise from the white goods industry is presented and supported by a case study. The advantages and disadvantages are set out, and any potential benefits gained from using an intelligent decision support system for plastic products’ design are introduced. The proposed decision support system contains human cognition within the field of design knowledge and special domain knowledge expertise regarding plastics supported by design methodology called ‘Design for Manufacturing’ (DFM).

Introduction

If we characterise computer aid within everyday life as being extensively applied, then engineering work is computer dependent. During a product development process, the computer aid is used from start to finish as computer hardware and software are the basic tools of each designer. A product development process is also a decision-making process. The engineer has to choose the proper tools when performing the design process, such as selecting the adequate software for the initial problem and, more importantly, he or she has to make several decisions whilst working with these tools, in order to achieve an optimal solution. Human cognition plays the key role in product development, as knowledge domain is crucial during decision-making process.

Existing Computer Aided Design (CAD) offers support during a great deal of engineering steps when designing a new product. CAD applications correspond to the designer’s work at drafting, drawing, modelling, assembling, analysing and simulating. Its limitations appear, when having to accept certain determinations and decisions about the product. This is very important as the following steps of the process are directly or indirectly dependent on these decisions. In other words, the process is a sequence of interdependent events and one decision at the early design stage would then exert influence on all successive events, and the final design solution. Experiences are an engineer’s main advantage. However the possibility of acquiring experts’ opinions is desirable, since they possess knowledge of specific design aspects and could contribute to the evaluation of possible design solutions. At the beginning of their careers, designers are in uncomfortable positions because of their limited experiences. This observation leads to the conclusion that adequate computer support is often needed for offering some advice and guidelines to designers during product development process. Such computer support for the decision process can be provided by the intelligent decision support system.

Although plastics are widely used in everyday life, most mechanical engineers are used to working with conventional materials, mostly metals. More than 120,000 plastics with very specific features have been developed and altogether they offer engineers more constructional options than all other materials together as is noticeable from material charts (Ashby, 2005). The inference from these facts is that, three major factors are involved with solving a material selection dilemma:

• Extensive number of plastic materials at disposal.

• Engineers’ education and work relevance are mostly in conventional materials.

• Lack of experiences in plastics design, except in plastic product oriented enterprises.

Enterprises, mostly small and medium-sized (SME) coping with mainly financial barriers realize that an expert team needed for new, optimal product development, is beyond their reach. The intelligent decision support system for designing plastic products presented in this article could be of major benefit, not only for SMEs, but also for those young inexperienced designers who have just started to design using polymers. Furthermore, this system could facilitate the work of experienced designers and/or offer them the opportunity to evaluate their material choices.

This article represents a proposed intelligent decision support system for specific design aspects, namely for plastic designs, and is organized as follows: Section 2 presents a comparison between conventional design and design using the intelligent decision support system, Section 3 is oriented towards polymers and the importance of related engineering, Section 4 describes a case study within a well-known company, where the new product development process is explained, emphasizing situations where decision support advisory system could be a major contribution to the engineering work, Section 5 envisages the intelligent decision support system for plastic design execution.