An integrated approach to product family redesign using commonality and variety metrics

Redesigning a product family entails carefully balancing the trade-offs between commonality and differentiation that are governed by the underlying platform architecture. Numerous metrics for commonality and variety exist to support product family and product platform design; however, rarely are they used in concert to help redesign platforms and families of products effectively. In this paper, we introduce an integrated approach that uses multiple product family metrics to establish an effective platform redesign strategy. Specifically, we present a detailed procedure to integrate the generational variety index, product line commonality index, and design structure matrix to prioritize components for redesign based on variety and commonality needs in a family of products. While all three of these tools exist in the literature and have been used extensively to support product family design, the novelty in our work lies in their integration to establish a redesign strategy for platform architectures that achieves a better balance between the commonality and variety within a product family. To demonstrate the proposed approach, case studies involving two generations of wireless computer mice and two families of dishwashers are presented. Ongoing and future work is also discussed.     

Modularity analysis and commonality design: a framework for the top-down platform and product family design

With a highly fragmented market and increased competition, platform-based product family design is recognised as an effective method for constructing a product line that satisfies diverse customer demand while keeping design and production cost- and time-effective. Recognising the need for modularity and commonality in platform development, this paper presents a systematic framework to assist in implementing top-down platform and product family design, which aims to achieve system-level modularity for variety generation, and rationalise the commonality configuration for module instantiation. In the first phase of platform development, a robust and flexible product family architecture is constructed to accommodate variations by analysing the external varieties of the generic product architecture, and provide a modularity design space, wherein the design tasks are further decomposed into module instantiation. The second phase of detailed platform development aims to enhance commonality in terms of engineering efficiency by coordinating with the back-end product realisation stage. A tractable optimisation method is used to capture and resolve the trade-off between commonality configuration and individual product performance. A family of power tool designs is used to demonstrate the potential and feasibility of the proposed framework at the system level and detailed design stages.     

From user requirements to commonality specifications: an integrated approach to product family design

Many companies design families of products based on product platforms that enable economies of scale and scope while satisfying a variety of market applications. Product family design is a difficult and challenging task, and a variety of methods and tools have been created to support this platform-based product development. Unfortunately, many of these methods and tools have been developed—and consequently exist—in isolation from one other. In this paper, we introduce an approach to integrate several of these disparate tools into a framework to translate user needs and requirements into commonality specifications during product family design. The novelty of the approach lies in how we integrate the market segmentation grid, Generational Variety Index (GVI), Design Structure Matrix (DSM), commonality indices, mathematical modeling and optimization, and multi-dimensional data visualization tools to identify what to make common, what to make unique, and what parameter settings are best for each component and/or subsystem in the product family. The design of a family of unmanned ground vehicles (UGVs) demonstrates the proposed approach and highlights its benefits and limitations.     

Product family platform selection using a Pareto front of maximum commonality and strategic modularity

Product family design offers a cost-effective solution for providing a variety of products to meet the needs of diverse markets. At the beginning of product family design, designers must decide what can be shared among the product variants in a family. Optimal design formulations have been developed by researchers to find one optimal component sharing solution based on commonality, cost or technical performance of a product family. However, these optimization methods may not be able to apply in consumer product design because some metrics (e.g., visual appeal and ergonomics) of a consumer product cannot be formulized. In this paper, we suggest a tradeoff between commonality and the quality of the modular architecture in product family platform selection. We introduce a method for designers to identify multiple component sharing options that lie along a Pareto front of maximum commonality and strategic modularity. The component sharing options along the Pareto front can be evaluated, compared, and further modified. We demonstrate the method using a case study of product family platform selection of high-end and low-end impact drivers and electric drills. In the case study, the quality of the modular architecture is evaluated using a design structure matrix (DSM) for each of product variants. Three architectures along the Pareto front with maximum commonality, optimal modularity, and a balanced solution of the two metrics are highlighted and further examined to validate the effectiveness of our method.     

Using product family evaluation graphs in product family design

Product family design and platform-based product development have garnered much attention. They have been used to provide nearly customised products to satisfy individual customer requirements and simultaneously achieve economies of scale during production. The inherent challenge in product family design is to balance the trade-off between product commonality (how well the components and functions can be shared across a product family) and variety (the range of different products in a product family). Quantifying this trade-off at the product family planning stage in a way that supports the engineering design process has yet to be accomplished. In this paper, we introduce a graphical evaluation method, the product family evaluation graph (PFEG), that allows designers to choose the ‘best’ product family design option among sets of alternatives based on their performance with respect to an ideal commonality/variety trade-off determined by a company's particular competitive focus, and guides designers towards a more desirable trade-off between commonality and variety in an existing product family. Two necessary supporting pieces for developing the PFEG are also proposed. One piece is the development of commonality and variety indices to quantitatively capture the degree of commonality and variety in a product family and its functions and components. We introduce two sets of commonality and variety indices–the CDI (commonality versus diversity index) for commonality (CDI_C) and variety (CDI_V), and the CMC (comprehensive metric for commonality) for commonality (CMC_C) and variety (CMC_V)–to achieve this. The other supporting piece is the development of a quantitative representation of the ideal trade-off between commonality and variety in a product family, known as the commonality/variety trade-off angle α, based on the elements that characterise a company's competitive focus and their industry-wide competitors. A linear regression model is used to link the qualitative competitive focus to a quantitative engineering perspective, and then to estimate the ideal trade-off angle. The commonality/variety trade-off angle can then be applied to the PFEG to help designers evaluate a product family or compare product family design alternatives. Most importantly, the PFEG is not just the graph of the two sets of indices; it is the representation of the commonality/variety trade-off relative to the desired competitive focus. Four families of power tools are used to illustrate how the computation of such indices supports product family design evaluation in the PFEG. In this paper, we only use the CDI in the example application, but the CMC can be computed using the same approach.     

A cost-based methodology for evaluating product platform commonality sourcing decisions with two examples

As more US companies source tooling development and manufacturing overseas in countries like China and Taiwan, are the need and primary drivers for product platforms diminishing? As tooling cost is reduced to a very small percentage of the total project cost, combined with availability of inexpensive purchased components and low labour rates, the need to develop product platforms can decrease substantially. Low cost outsourcing has given firms the ability to develop and manufacture products cheaply without having to spend the additional time and effort to develop product platforms and families. In this paper, two examples involving two consumer product companies and their product lines are presented. Product family components and estimated tooling costs are analyzed, as well as development timing and profit margins to demonstrate why companies are moving away from product platforms in certain types of consumer products. A novel methodology using component commonality decisions relating to major cost drivers is introduced and applied to both examples. Based on the evidence from the examples presented in this paper, there appears to be little financial or functional benefit to develop product platforms that share common components or subsystems when these products are being manufactured offshore; however, even when considering outsourcing, platform-based product development principles can still yield tangible improvements in production costs over the life of the product.     

The application of the entropy measure to the analysis of part commonality in a product line†

Given the objective of determining the degree of part commonality in a product line, this study discusses several methods of analysis which are possible. The use of the entropy measure, H= ? σpi log pi, is investigated as a plausible alternative to current procedure. The methodology will incorporate a simulation of several types of distributions of part usage which might occur in a typical application. An analysis of the results will compare the entropy approach with existing practice.     

Joint decision of product configuration and remanufacturing for product family design

Product family design (PFD) is a popular method for increasing product variety to satisfy the needs of diversified markets. With the increasing concern for environmental friendliness in society, more and more companies develop launching remanufactured products and include them in their product families. Therefore, PFD should be considered in a broad decision space where configuration of product variants and remanufacturing are considered simultaneously. However, this issue was not addressed properly in previous research. In this paper, a methodology for joint decision of product configuration and remanufacturing is proposed in which a bi-objective mixed integer programming model is formulated to determine the configurations of both new and remanufactured products for minimising product cost, maximising total market share, and satisfying reliability requirements. Then, Non-dominated Sorting Genetic Algorithm II (NSGAII) is adopted to solve the optimization problem. Computational experiments were conducted and their results show that NSGAII is convergent to the model well. A case study is presented to illustrate the applicability and effectiveness of the proposed methodology.     

Switchgear component commonality design based on trade-off analysis among inventory level,delivery lead-time and product performance

The shortening of product delivery lead-times can usually be achieved by keeping high-level components in inventory, however in small-volume production systems, maintaining such inventories is often a costly as well as a risky business strategy. If the risk of maintaining unsold inventory can be decreased, even small-volume manufacturers may be able to justify holding more significant quantities of versatile inventory. This paper discusses a component commonality effect to breakthrough the trade-off relationship between inventory levels and delivery lead-times for such small-volume production systems. By using the same component in different products, inventory maintenance costs can be dramatically reduced, but component commonality design problems are inherently complex, since excessive module commonality may lead to lower product performances, and there are trade-off relationships between product performance and cost reductions obtained through component commonality. In this paper, such a design problem is formulated as a multiobjective component commonality design optimisation problem considering inventory level, delivery lead-time and product performance, and the optimal solutions are obtained as a Pareto optimal solution set. Detailed procedures concerning the proposed design method, including inventory simulation, are discussed and developed for a switchgear design problem. Finally, an example switchgear design problem is solved to illustrate that optimal use of component commonalities across different modules can significantly reduce inventory costs, while also shortening product delivery lead-times.     

Assessing and improving acoustic radiation force image quality using a 1.5-D transducer design

A 1.5-D transducer array was proposed to improve acoustic radiation force impulse (ARFI) imaging signal-to-noise ratio (SNRARFI) and image contrast relative to a conventional 1-D array. To predict performance gains from the proposed 1.5-D transducer array, an analytical model for SNRARFI upper bound was derived. The analytical model and 1.5-D ARFI array were validated using a finite element modelbased numerical simulation framework. The analytical model demonstrated good agreement with numerical results (correlation coefficient = 0.995), and simulated lesion images yielded a significant (2.92 dB; p < 0.001) improvement in contrast-tonoise ratio when rendered using the 1.5-D ARFI array.     

Assessing comparative production efficiencies for product line management

Product line management involves product expansion or elimination depending on various factors, for example, production processes and demands in the market. This study focuses on measuring product performance for a firm’s product line management, using parametric and non-parametric approaches. First, we choose variables related to the production and demand of products and assess the comparative performance of product groups and individual products using data envelopment analysis (DEA). Second, we attempt to detect possible performance differences among the product groups using one-way analysis of variance. Third, we identify the sources of inefficiency using appropriate DEA scores and offer some managerial insights. Last, we try to confirm the determinants of product performance using Tobit regression analysis. The major contribution of this study is the use of a novel approach for product line management by measuring the performance of product groups and individual products using pertinent variables. The approach used in this study is applicable to various manufacturing and service industries. The limitations of this study are the number of product groups selected and examination of performance using cross-sectional data.     

Integrated innovative product design and supply chain tactical planning within a blockchain platform

In globalised manufacturing and production environments, companies increasingly tend to exploit public contribution advantages within designing, manufacturing and marketing processes. To be benefited from outbound capabilities, this paper presents a tactical supply chain planning model to integrate the designing process in the form of open innovation within the supply chain main processes. In this regard, a fuzzy mathematical model is proposed to optimise the tactical decisions according to supply chain objectives and open innovation considerations. On the other hand, intellectual property issues and protecting the rights of innovators are significant concerns that sometimes avoid companies to be engaged in open innovation initiatives. Therefore, this paper proposes a registering mechanism in which the ideas and creative works are collected, refined and finally approved within a blockchain platform. Furthermore, in order to deal with epistemic environmental uncertainty, the fuzzy set theory is utilised. To investigate the applicability of the developed model, a case study in home appliances domain is employed. The results show that the company can achieve favourable designs by spending approximately 1% of the supply chain total cost. Additionally, benefiting the registering mechanism can decrease the cost of using non-original designs more than 41%.     

MOORA-based Taguchi optimisation for improving product or process quality

In this study a multi-objective optimisation on the basis of ratio analysis (MOORA)-based Taguchi application is used to solve multi-response optimisation problems. In this application, the MOORA method is integrated with the Taguchi method to convert the multi-response problem into a single-response problem. Four examples are considered in this paper for illustrative purposes. The MOORA-based Taguchi method is simple and robust compared to the other MADM methods, such as TOPSIS, VIKOR and GRA. The proposed model reduces the time associated with the amount of calculation steps significantly. We found that solution results of the MOORA-based Taguchi application and other hybrid models in the literature were not significantly different. The MOORA-based Taguchi application offers also a new tool in the optimisation of Taguchi’s multi response problem.     

RMS capacity utilisation: product family and supply chain

The paper contributes to development of RMS through linkage with external stakeholders such as customers and suppliers of parts/raw materials to handle demand fluctuations that necessitate information sharing across the supply chain tiers. RMS is developed as an integrated supply chain hub for adjusting production capacity using a hybrid methodology of decision trees and Markov analysis. The proposed Markov Chain model contributes to evaluate and monitor system reconfigurations required due to changes of product families with consideration of the product life cycles. The simulation findings indicate that system productivity and financial performance in terms of the profit contribution of product-process allocation will vary over configuration stages. The capacity of an RMS with limited product families and/or limited model variants becomes gradually inoperative whilst approaching upcoming configuration stages due to the end of product life cycles. As a result, reconfiguration preparation is suggested quite before ending life cycle of an existing product in process, for switching from a product family to a new/another product family in the production range, subject to its present demand. The proposed model is illustrated through a simplified case study with given product families and transition probabilities.     

An approach to conceptual and embodiment design within a new product development lifecycle framework

The design of new innovative products is the result of an accurate and precise management of knowledge sources all over its life cycle, such as technology, market, competitors and suppliers. The work contributes with a framework that shows how the knowledge sources influence in the state-of-the-art and market needs so that they become opportunities for innovating products addressing the whole product life cycle. It provides a systematic path from the early generation of ideas to the production of a new product proposal. Through a deep analysis of previous research works of new product innovation life cycle development frameworks and linking it with knowledge management, strategic planning and scorecards, we came out with a structured contribution. The result considers the concurrent activities and its relationships all the way through the product life cycle that can help in creativity and innovation, combined with a process management proposal. Managing the sources of knowledge in highly dynamic markets and technologies is one of the major difficulties involved in innovative products design and development. The emerging knowledge from external sources is confronted with organisation internal knowledge and experience in order to achieve the first product correct.     

A product-configuration-driven system for assembly planning within a product data management environment

This paper describes the results of a project sponsored by the Engineering and Physics Science Research Council (EPSRC) in collaboration with leading engineering and consultant companies, which is aimed at developing new methodologies for Computer-Aided Assembly Process Planning (CAAPP). The aims of this project were to investigate contemporary industrial requirements for CAAPP, study the feasibility of integrating CAAPP with data management tools via a product model and review current state-of-the-art systems and methodologies. The research has been focused on finding solutions to some of the limiting factors that have kept CAAPP an immature technology for many years. The deliverable of the research project is a novel assembly planning system, which has been developed in a Product Data Management (PDM) environment. The system takes the product configuration model derived from the PDM system as the input. This input is analysed by the system using intensive built-in knowledge to yield detailed assembly plans. The system achieves integration of CAAPP functionality with a PDM tool, providing a data control framework and a high-level data structure to form the basis of planning. The prototype system has an automatic planning module and an interactive planning sub-system that complements it. The interactive planning module also allows the user to capture the assembly knowledge and model it as a flowchart in the system. As fully automatic planning is a new field, comparison of automatically generated results with those of the semiautomatic system help to evaluate the system and build up user confidence.     

Development of a production cost estimation framework to support product family design

The main task of a product family designer is to decide the right components/design variables to share among products to maintain economies of scale with minimum sacrifice in the performance of each product in the family. The decisions are usually based on several criteria, but production cost is of primary concern. Estimating the production cost of a family of products involves both estimating the production cost of each product in the family and the costs incurred by common and variant components/design variables in the family. To estimate these costs consistently and accurately, we propose a production cost estimation framework to support product family design based on activity-based costing (ABC), which consists of three stages: (1) allocation, (2) estimation, and (3) analysis. In the allocation stage, the production activities and resources needed to produce the entire products in a family are identified and classified with an activity table, a resource table, and a production flow. To help allocate product data for production, a product family structure is represented by a hierarchical classification of products that form the product family. In the estimation stage, production costs are estimated with cost estimation methods selected based on the type of information available. In the analysis stage, components/design variables possible for product family design are investigated with resource sharing methods through activity analysis. As an example, the proposed framework is applied to estimate the production cost of a family of cordless power screwdrivers that share different components within the family.     

Simultaneous design of a product family and its related supply chain using a Tabu Search algorithm

Product family design is currently facing a multitude of challenges, the main problem stemming from the diversity offered to consumers. To design a product family, designers have to define an efficient bill of materials which ensures product assembly within a predefined length of time in order to satisfy the synchronised delivery principle. In addition, the modules used to assemble the finished products have to be competitive in terms of logistical costs. The ability to anticipate the constraints associated with the production process and with transportation is consequently of great interest. In this paper, we focus on the process of identifying a set of modules to be used in the assembly of the finished product. The objective is to define the bill of materials for each product from the modules belonging to that set, and to assign these modules to distant facilities where they will be manufactured and then shipped to a nearby facility for final assembly within a specific time. We use a set partitioning formulations to represent the problem, and solve it by adapting a Tabu Search algorithm in which the assembly process and the supply chain design are considered at the same time.