Design for mass customization: Product variety vs. process variety Joanna Daaboul, Catherine Da Cunha, Alain Bernard (1)*, Florent Laroche Ecole Centrale de Nantes, IRCCyN UMR CNRS 6597, 1 rue de la Noe¨, BP 92101, 44321 – NANTES Cedex 3, France 1. Introduction In order to survive in today’s competitive economy, and to satisfy more demanding customers, companies are implementing mass customization (MC) which is defined as producing personalized products at a price similar to that of mass production (MP) [1]. MC can be offered via product and process variety. Product variety is defined as the diversity of products that a production system provides to the marketplace [2]. Process variety is the diversity and complexity in the processes due to product variety and process alternatives for each product variant [3]. Designing products for MC remains a main challenge for a company, thus we propose a metric based approach that is able to evaluate both product and process variety based on their impact on the perceived value for the customer, since in MC the whole value network focuses on the customer who is its main driver. Product variety and process variety are presented in Sections 2 and 3, respectively, and then we define value in Section 4. We study the influence of both product and process variety on customer perceived value in Section 5 and in Section 6, the whole method using the value metric is described. In Section 7 a case study in the shoemaking industry is set out and in Section 8, discussions are presented. 2. Product variety The product is the centre of a value network. The goal of collaborating partners is to deliver to the customer a product generating value both for him/her and different partners in the network. The entire value network starts with a ‘‘good’’ design. But, in the case of MC, the design of the product embeds defining customization possibilities. And to keep the cost of product close to that of mass production, customization is assured via modularity, and commonality in product design. They both allow a differentiation of products while minimizing the internal complexity, cost, and time resulting from such differentiation by shortening the delivery lead times and enjoying economies of scope [2]. Moreover, approaches such as product family, product platform and product architecture have been recognized as effective means of accommodating increasing product variety while still achieving economies of scale [4,5]. Nevertheless, it remains a difficult task to design a product intended to be mass customized, therefore Tseng et al. [6] proposed a design approach for MC (DFMC). The core of their approach is to develop a MC oriented product family architecture (PFA) with a meta level design process integration as a unified product creation and delivery process model. A constructional-theory-based method formed by six steps for mass customized products was proposed by Hernandez et al. [7]. The first step is to define the space of customization which is the set of all combinations of values of product specifications that an enterprise is willing to satisfy. The second one is to formulate an objective, which can often be the minimization of cost. The third step is to identify modes for managing product variety such as adjustable controls, modular combinations and dimensional customization that are used to customize the product. In the fourth step the number of hierarchy levels is determined and the modes for managing product variety are allocated to these levels. The fifth step consists of formulating a multi-stage optimization problem, while the sixth and final step is to solve this problem. Some of the advantages of this method are cost-effectiveness, its applicability to any distribution of demand, its suitability for small or large variety in product specifications, and adaptability of the product line. Its limitation is the need to formulate an objective function that includes all the various costs involved in a product design. 3. Process variety Process platform planning is as necessary as product platform planning, since the customization of a product leads to exponen- CIRP Annals - Manufacturing Technology 60 (2011) 169–174 ARTICLE INFO Keywords: Design Customization Variety ABSTRACT Mass customization (MC) has become a reality and cannot be neglected as one of the leading strategies in satisfying customers and assuring companies survival in today’s markets. MC can be offered either via product variability or process variability. How this is achieved using both approaches is the main core of this article. After an overview of related works, the influence of design variability on the overall generated value of the product is studied via a metric approach. A case study of the shoe industry is also presented, based on the experience of a European project called Dorothy. ß 2011 CIRP. * Corresponding author. Contents lists available at ScienceDirect CIRP Annals - Manufacturing Technology journal homepage: http://ees.elsevier.com/cirp/default.asp 0007-8506/$ – see front matter ß 2011 CIRP. doi:10.1016/j.cirp.2011.03.093