Manufacturing process selection in engineering design. Part 2: a methodology for creating task-based process selection procedures

Part 1 (A.M. Lovatt, H.R. Shercliff, J. Mater Des., 19 (1998) 205–215) of this paper identified a need for a methodology to help to create selection procedures for specific manufacturing tasks, where the material and processing operation have, to some extent, already been defined. This paper develops such a methodology, and its aims are twofold: firstly to guide the designer through defining the requirements of the design and identifying the attributes of the relevant subset of processes which must be considered; secondly to lead the designer through an evaluation of a design considering both technical viability (including the product quality during processing and in the finished part), and economic viability. A critical development in this work is the incorporation of process modelling into the selection procedure, as a tool for capturing the coupling of material and process characteristics which govern whether the processing and performance targets can be met.     

Application of a systematic design methodology: an engineering case study

The basic steps of a design process have been reviewed and applied to seek an optimum solution for an industrial design problem. The problem was about a mechanical swivel-joint in a sea-current-metering system for underwater marine use. It was expensive ($200) and not functioning properly because of rattling and high friction between parts. The objective was to design another joint of better performance and lower cost, if possible. Ten steps were defined and carefully followed to solve the problem. This led to the design and production of a good quality swivel-joint as far as performance, appearance and other aspects were concerned and the cost reduced by 40%. This design method, in addition to yielding good results, is suitable for the organization of the activities of new designers and design students.     

Filtration in materials selection and multi-materials design

Materials selection methods by free searching consist in four steps: translation, filtration, classification and documentation. The second step, limiting the field of solutions, must be analysed accurately when the constraints are related with free design parameters. This paper describes methods to deal with this filtration step in the cases of materials selection and multi-materials design. The classical filtration in single materials selection is extended to cases with several free geometric parameters. Then, a filtration approach for multi-materials design with undefined number of components and free geometric parameters is proposed. Finally, a case study concerning the design of a pipe material for offshore oil extraction is presented. The application of this work allows a preliminary elimination of unsuitable materials in the definition of multi-materials components, so it will be useful to avoid long numerical studies.     

Digital tools for material selection in product design

The increasing number of normalized materials, promoters and users led to a significant amount and diversity of databases and software for material selection, presenting differentiating abilities for the materials selection process.     

Numerical simulation of damage evolution in multi-pass wire drawing process and its applications

This paper presents a numerical simulation of damage evolution in multi-pass wire drawing process and its potential relevance to manufacturing design. The Gurson–Tvergaard–Needleman model (GTN model) is introduced to describe damage evolution in the drawn wire. Based on a three-dimensional model of the drawn wire generated through ABAQUS, the numerical analyses on damage behavior in multi-pass wire drawing are undertaken for the purpose of investigating the damage evolution during all phases of the process. Convergence problems in the process of simulation are discussed. The results illustrate the damage evolution of the drawn wire in each of the eight passes and the damage distribution along axial and circular directions. It turns out that the damage values continuously rise up with the increase of drawing passes and the damage evolution in the drawing process shows obvious nonlinear characteristic. The damage distribution along axial and circular directions agrees well with actual drawing situation. Wire breakage is expected to occur in those areas of the drawn wire where fractures most possibly initiate. Furthermore, the numerical analyses contribute a new approach for the optimization of the drawing parameters. Based on the principle of least damage accumulation in the drawing process, the optimal area reduction is chosen and selection of material processes is proposed. The currently standard 8-pass wire drawing process can be potentially optimized by a proposed 7-pass wire drawing process.     

Drawing,flanging and hemming of metallic thin sheets: A multi-step process

This study deals with the multi-step classical hemming process on samples with complex geometries and a pre-strain state linked to the forming of curved surface. The influence of taking the anisotropy and the Bauschinger effect into account on the roll-in and loads is studied. The design of a specific device was realised so as to compare the numerical results and the experimental values. The simulations show a certain relevance in the use of shell elements compared to solid elements despite their use restriction, and good correlation between the calculations and the tests. The roll-in differences and the level of stress reached are low at the end of pre-hemming and hemming, although a significant rotation of sections which are initially perpendicular to the mean fiber is observed during flanging.     

Jointing of high-loaded composite structural components. Part 1. Design and engineering solutions and performance assessment

The author presents and discusses the results of investigation to verify the design principles for jointing composite components. Based on the findings, novel design and engineering solutions for metal-composite joints are put forward. To ensure an effective transition from a composite material to a metal butt-joint fitting, new jointing techniques have been developed involving the use of embedded longitudinal and transverse fastening microelements in a composite material, which are molded into or mounted on a metal component. A modification of half-stitch jointing is proposed which enables the joint to work in compression and reduces the pressing stresses in the winding zone. Based on the study of force transfer conditions in the proposed joint design and the jointing solutions, the author defines the main lines of theoretical and experimental investigations to support the engineering and stress analysis activities. The experimental static strength assessment demonstrates effectiveness of the proposed solutions. __________ Translated from Problemy Prochnosti, No. 3, pp. 23–33, May–June, 2006.     

Feature-based metal stamping part and process design. Part I: stampability evaluation

It is essential to devise a representation scheme for the metal stamping part design which allows the designer to capture and reason the design information, and ultimately, to take various considerations into account and make evaluation decisions. In our research, the feature-based approach is used to represent the metal stamping part, and feature-based metal stamping part and process design has been studied and presented in a two-part paper. This is the first of a two-part paper focusing on stampability evaluation. In Part II a feature-based stamping process planning approach is investigated. This paper presents a feature- and knowledge-based stampability evaluation system. Tasks of this research include identification of the aims, criteria, and procedure of stampability evaluation, as well as the formalization of the stampability evaluation knowledge. Stampability evaluation is classified into stampability verification and stampability measurement. Stampability verification is used to determine whether a part design is stampable or not. Stampability measurement can be employed to select a best design from stampable candidate designs. Based on the stamping design feature definition, a stampability-coding scheme with incorporated knowledge has been developed to enable comprehensive stampability evaluation. Finally, a case study demonstrates the feasibility of such stampability evaluation system.     

Introducing a novel method for materials selection in mechanical design using Z-transformation in statistics for normalization of material properties

Optimum materials selection is a very important task in design process of every product. There are various materials selection methods like Ashby’s method or digital logic methods such as DL and MDL. In the present research work the Z-transformation method is proposed for scaling the material properties to overcome the shortcoming of MDL method. The results show that despite the simple scaling function used, the ranking procedure is as powerful as MDL method and even it is superior to MDL when it ranks the less important materials existing among a list of candidate materials.     

The role of topology in engineering design research

Aspects of the mathematical specialty of topology appear within several seemingly distinct areas of engineering design and engineering design theory. Indeed, the expression topology of a design is often used informally. In this article a primary intent is to demonstrate the diversity of applications of topology within engineering design. A complementary goal is to introduce the engineering design community to topology as a rich, formal, well-established mathematical discipline that may be of value for wider study. Upon reviewing some of these topological applications, it appears that topology holds promise as a basis for formalizing engineering design theory. This article considers topology as a basis for unifying design abstractions. The potential benefit may be the realization of commonalities between design aspects previously considered separately, where each now has its own attendant specialized, expensive analyses.     

基于系统工程过程的维修性设计要求生成过程研究

维修性设计要求的生成是维修性工作的一个重要组成部分,然而目前还没有有效的方法和过程支持该项工作的开展.借鉴系统工程过程的基本步骤,结合产品的一般研制程序,提出维修性设计要求的一体化生成过程,该生成过程包括维修方案的生成、维修性指标的确定与分配、维修性设计要求的生成三个主要工作,并对各项工作过程进行了详细的阐述.     

A co-operation framework for product–process integration in engineering design

Many different studies have stressed the importance of co-operation in engineering design. This paper is based on an empirical study carried out over 18 months and based on fieldwork where the researcher worked in a design team as a mechanical engineer. The question of product–process integration is particularly critical in mechanical engineering and requires the development of specific co-operative procedures. Our results stress the importance of artefacts as intermediary objects in the design process and more specifically in the development of co-operative processes. We developed a framework centred on three conceptual levels:

• At product level, where we developed specific artefacts within a CAD environment, referred to herein as co-operating features,

• At organisation level, where we stress the importance of developing organisational learning and a new interface role,

• At actor level, where we stress the importance of developing reflective practices.

This conceptual framework aims to provide a foundation to develop instrumental settings for design co-operation.     

Manufacturing knowledge verification in design support systems

This paper identifies the need for a verification methodology for manufacturing knowledge in design support systems; and proposes a suitable methodology based on the concept of ontological commitment and the PSL ontology (ISO/CD18629). The use of the verification procedures within an overall system development methodology is examined, and an understanding of how various categories of manufacturing knowledge (typical to design support systems) map onto the PSL ontology is developed. This work is also supported by case study material from industrial situations, including the casting and machining of metallic components. The PSL ontology was found to support the verification of most categories of manufacturing knowledge, and was shown to be particularly suited to process planning representations. Additional concepts and verification procedures were however needed to verify relationships between products and manufacturing processes. Suitable representational concepts and verification procedures were therefore developed, and integrated into the proposed knowledge verification methodology.     

Modular design of product families for quality and cost

The purpose of this article is to help managers early in the design of new product families. Based on product structures, sales forecasts, and constraints imposed by the marketplace, like quality and cost, the proposed method selects the product modules that meet customer requirements for the products, while respecting those constraints. The proposal includes a single-level module design formulation that considers quality and cost simultaneously. The method for testing the proposed algorithm is based on a case study of an electro–mechanical assembly device (headlamp). The performance of the algorithm is compared to that of the zero module case, where often the constraint problem cannot be resolved. The main result is a model and an algorithm that optimise quality and cost under the constraints of quality and cost. It shows what modules to manufacture, in what quantities, and in which products to use them. The output also provides the predicted quality and cost, based on improvements made to the modules. To conclude, this research enables the joint optimisation of quality and cost by defining the modules to be manufactured. It provides input for managers seeking modules designed for their supply chain. The algorithm provides key input for managing production ramp-up.     

Integrated development of CFRP structures for a topless high performance vehicle

When modern saloon cars are re-engineered as convertibles (or roadsters) it is typical for them to lose 50% or more of the body’s torsional rigidity. Consequently the vehicles rarely handle quite as crisply, nor do they ride as well as the coupes from which they derived. This paper highlights the fundamental contributions of advanced composites in achieving the desired value of handling of the Murcièlago Roadster without penalizing the overall weight of the vehicle. To compensate for the absence of the roof structure, the vehicle was strongly redesigned by introducing new structural members and reinforcing existing critical components. A new all-carbon/epoxy composite sub-frame, which spans the entire engine bay, is comprised of elliptical tubular members, and it is the first of its kind in a production vehicle. Engineering of the sub-frame, from preliminary design to manufacturing decisions, is the focus of this paper, and is achieved through a Building Block approach that sets the program within the Integrated Product Development (IPD) strategy that the Advanced Composites Division of Automobili Lamborghini S.p.A. employs for its technology demonstrators. The strategy consists in a concurrent analytical and experimental development of the product, from the initial conceptual design and coupon testing, through the stages of element and subcomponent engineering, to final component manufacturing.     

A knowledge-based system for materials selection in mechanical engineering design

This paper studies various work on the development of computerized material selection system. The importance of knowledge-based system (KBS) in the context of concurrent engineering is explained. The study of KBS in material selection in an engineering design process is described. The development in materials databases, which sometimes serve as material selection packages, is also discussed. The use of KBS in material selection and the application in the domain of polymeric-based composite are chosen as typical examples.     

Revisiting the role of selection for the evolution of industries

Despite a growing reliance on evolutionary theories when explaining industrial dynamics, the mechanism of selection has received limited attention. Selection is often taken for granted and conceptualised as product market competition. We go beyond this view and distinguish between different types of selection—formal and social—and consider how these lead to different entities being selected. Formal selection relies on codified selection criteria and often applies in selection environments where processes are standardised and institutions formalised. Social selection relies on reputation, referrals and previous interactions in order to evaluate intangible properties of the entities being selected. We argue that firms compete in multiple selection environments, not limited to product markets, that different selection environments may rely on different types of selection and that this has profound implications for industrial dynamics. This theoretical discussion is inspired by empirical observations of the medical technology industry in Sweden.     

The role of design in product and process change

Innovation in engineering design and manufacture is discussed with reference to the competitiveness of the UK industry. It is suggested that successful design is a dynamic process that must be adjusted and redefined continually to meet changing demands.