No abstract

In concurrent engineering, the integration of the designers' knowledge and experience, and computer technology into the design process is very important to improve design quality and production efficiency. A feasible design alternative that follows the design rules for assembly will make product manufacturing and assembly more successful. However, designers seldom consider assembly problems in their product development processes. This drawback often occurs due to conflicts in communication between the design and production departments and will cause severe assembly and manufacturing problems. To assist designers with the assembly issue in the design process this research presents a contact relation matrix (CRM) approach to generate assembly sequences for product design. The procedure developed for the CRM approach is based on the four rules identified from the part contact relations and a matrix representation to match the recommended design alternative with the four rules. A procedure is then employed to identify the assembly priority for the recommended design alternative. The part assembly sequence is generated with a sorting procedure. A hand-held hairdryer and an Italian style coffee maker are used as cases to help explain the feasibility of the CRM approach. The results from this study should help designers to examine the possible part combinations and make the necessary modifications for the recommended design alternative. The CRM approach can also be linked with an existing matrix approach in generating and evaluating design alternatives. By integrating the CRM and matrix approaches, the design quality and efficiency will be greatly improved.

During the process of concurrent design, a designer must focus on meeting the changing requirements of customers and reacting to the rapid decrease of the life-cycle of the product in a dynamic market. However, the cost induced by the quality delinquent and aftermarket service is a critical factor in the enterprise profit. This research proposes a product design methodology that integrates the grey relation approach to quality function deployment (QFD) and quality engineering (QE) to solve the problem. It is noted that the process increases customer satisfaction and enhances product quality in response to global competition. Based on the results of systematic market research performed on customer requirements ( CRs), the hierarchical clustering technique and grey theory have been applied to identify, categorize, and evaluate CRs to rank their grey relational importance. The critical design characteristics ( DCs) have been identified using QFD, which applies the semantic differential method on the relationship matrix cell to evaluate their relationship with CRs. The selected DCs are then evaluated to determine noise and possible loss of quality using the orthogonal experiment of the Taguchi method. The objective of the optimization process is to integrate QFD and QE into the development process and to optimize the quality of product development. With support from a timer manufacturer, six existing products have been selected to demonstrate the applicability of the approach described above. This robust product design process provides encouraging evidence for a new approach that can improve quality, reduce variation, and increase customer satisfaction and enterprise profit.

Concurrent engineering design is widely used to shorten the time needed to introduce a new product and to enhance the quality of the design of the product. However, designers seldom consider the difficulty of assembling a product's components and modules in the concurrent development process. In fact, the concept of design for assembly is not new. Planning the execution of assembly operations and selecting the assembly sequence during product development will provide designers with interrelated information of design and manufacture that help reduce manufacturing problems. The designer should realize that a reasonable assembly sequence for a product has a significant effect on the efficiency of the entire assembly process. This research focuses on the enhancement of the contact relation matrix approach to the generation of assembly sequences in a product design procedure. A systematic and efficient assembly sequence assistance procedure is proposed to generate feasible assembly sequences and to find an optimal sequence to assemble the product. Compared to the complexity of other methods, this research proposes a modularized contact-rule reasoning approach to generating assembly sequences. The general approach of this research is to (a) develop a modular method for assembly sequence planning, (b) use matrix operations to facilitate the generation of assembly sequences, and (c) generate the assembly sequence of the designed product by searching for subassembly extraction rules. The assembly sequences are then created in the form of a hierarchical structure. The results will assist designers to consider and reduce some manufacture problems in advance that might occur in the process of generation of the recommended design alternative.