Mass Customization Mitchell M. Tsenga, S. Jack Hub, Yue Wanga a: The Hong Kong University of Science and Technology, Hong Kong b: University of Michigan, USA Abstract: Mass customization aims to deliver customized products with near mass production efficiency. It has gained much attention from both academia and industry since its emergence. The paradigm of mass customization is imperative for many companies to survive in the fragmented, diversified, and competitive marketplace. This survey gives an introduction to mass customization from the perspectives of design for mass customization, design for personalization and point out some future directions for the development of mass customization. Keywords: Mass customization, personalization, customer requirements

1. Introduction

Mass customization aims to deliver products and services that best meet individual customers’ needs with near mass production efficiency (Tseng and Jiao 1996). In this paradigm, it is critical to provide individually designed products and services to every customer through process agility, flexibility, and integration. A brief summary about the basic properties that make mass customization unique is summarized as table 1. Mass Customization Delivering affordable goods and services with enough variety and customization Goal that nearly everyone finds exactly what they want Economies of scope and customer Economics integration

Variety and customization through Focus flexibility and responsiveness Product family and standardized modules Product assembled based on customer needs  Upredicatable demand pattern  Heterogeneous niches  Low-cost, high-quality, customized Key Features

goods and services  Short product development cycles  Short product life cycles

Organization

Flexible and adaptive In order to meet the customer requirements with efficiency and effectiveness, active customers’

Customer

involvement though out the product life

Involvement

cycle is essential. Thus, user innovation, co-design, customer configuration

and

others have become important tools in MC.

Table 1: Properties of mass customization (adapted from Chen et al. 2009)

Mass customization was first coined by Stan Davis in Future Perfect (Davis 1987) and later developed by Pine (1993), which embarks a paradigm shift for the enterprise that offers products and services best fitting to individual customer's needs while still keeping near-mass production efficiency (Tseng and Jiao 2001). The key feature of mass customization is the capability to integrate the product varieties derived from the individual customer's needs and desire and the efficiency of mass production, so that the product is affordable due to low product cost achieved by the production scale of economy.

The essence of mass customization is to transform a customer to "co-designer", in which the customer is able to get access to the design process, such as concept design

and product development, by expressing the requirements or even co-designing the product with the configuration toolkit (Tseng and Piller 2003). Dell's PC customization service is a typical case.

Mass customization changes the design and production from "made-to-stock" to "made-to-order". It challenges the conventional product development approaches and supply chain management, from mass production to "high-variety-low-volume" production. In order to support the paradigm shift derived by the customization process, the enterprise should reconsider the whole value chain from the front-end to balance three important factors, time-to-market, variety, and economy of scale.

In addition, mass customization can also improve inventory and supply chain management efficiency. As mass customization is a make-to-order process, usually products are only made when the purchase order is placed. Thus, the shift from “made-to-stock” to “made-to-order” can significantly improve the production and supply scheduling and reduce the inventory cost and the risks of investment in materials and product development that will not encounter the preference of consumers. Furthermore, mass customization can be conducted online in some cases, so that many providers even sell shoes completely online without any physical stores, such as Zappos. This strategy can further reduce the operation and rental costs by online direct channel sales and increase the profit margin rate (Tseng et al. 2003). Even for those providers still with physical stores, they no longer have to show a full inventory of selection in all stores.

2. Design for Customization

Design for mass customization is to consider economics of scope and scale at the early stage of product development process (Tseng and Jiao 2001). The main

emphasis is on elevating designing individual products to designing a product family with a common platform, to which modularity and commonality are the foundations. Based on the variants of the modules, a high number of assembly combinations or product variants can be created so satisfy the wide range of consumers (Hu et al. 2011). This section will review some of the important steps used to realize mass customization, namely understanding customer needs, commonality and product family architecture, and the manufacturing techniques for mass customization.

Understanding customer needs One crucial step of design for mass customization is to understand individual customer's needs first. As a "co-designer", the customer can directly interact with the producer to express the requirements or even directly design the product, usually through web-based interface. To enhance the interaction with customers, many companies employ the customer's co-design interface to increase customers' confidence and educate them about the product, which will transfer the purchasing to a more enjoyable entertainment (Piller and Tseng 2010; Wang and Tseng 2011b). Product configurator is among the most widely used toolkits to elicit customer needs. Basically, a product configurator consists of a set of predefined component or attributes and constraints on combining this component. It takes customer needs as input and the output is the desired product variant. Traditional study on product configurations focuses on the reasoning in configurations, modeling of configuration knowledge, the reuse of configuration. One trend in current product configuration research is to incorporate more business intelligence factor into configurators, such as product recommendation (Freuder et al. 2003; Junker and Mailharro 2003; Juha and Alexander 2008; Wang and Tseng 2012), customer emerging needs detection (Hauser

and Urban, 2004;Wang and Tseng 2013) and improving the efficiency of eliciting customer needs (McSherry 2003, Wang and Tseng 2007 and 2011a; Jalali 2012).

Modularity and product family architecture Customer's needs are then translated into the variant modules, while keeping the rest constant to achieve economy of scale, leading to modularity and commonality issues in design for mass customization. Modularity is the decomposition of product structures and applicable to describing product type, and commonality resembles the grouping of similar product variants of a specific product type characterized by modularity (Jiao et al. 2007; Hu et al., 2011). High degree of modularity can address customer's unique preference, but it increases assembly cost and other related cost as well. Therefore, there is a balancing point of commonality and modularity.

The commonality and modularity concepts are integrated into product platform-based development approaches to develop the product family. Product family has been well recognized as a rationale of achieving mass customization. Product family offers a systematic diagram which defines product platform, product architecture, and product family. Product platform is “a set of subsystems and interfaces developed to form a common structure from which a stream of derivative products can be efficiently developed and produced” (Meyer et al., 1997). Product architecture is mainly concerned with how a product is arranged into physical units and how these units interact (Ulrich et al, 1995). With various adoptions of different product models, Erens and Verhulst (1997) described the architecture of product families. Fujita and Ishii (1997) discussed design for variety in terms of structuring essential tasks and issues associated with variety design. They also tried to optimize the system structure and the configuration of product families simultaneously (Fujita and Isshii, 1998).

However, their work focuses on computational support instead of product architecture planning. Tseng and Jiao recognized the rationale of a product family architecture (PFA) with respect to design for mass customization. They addressed an efficient method to tailor different products according to different customers’ requirements based on common product family platform. They also observed the difference between customer-perceived variety in terms of functionality and technical variety, which results in different variety design themes.

There are two types of prevailing product family design, scalable product family design and configurational product family design (Jiao et al, 2006). Simpson first proposed the scalable approach by using scaling variables to in different dimensions to satisfy a variety of customer needs (Simpson, 2004). There are two major tasks in scalable product family design. The first one is to determine the appropriate platform. It is followed by the step of optimizing common and distinctive variables values to better satisfy performance and economics requirements. In a nutshell, the scalable product configuration is to employ scaling variables to shrink or stretch the platform in various dimensions to satisfy diverse customer needs while other variables are kept constant. Thus, the important issues are to first decide which variables take common value in the product family and then determine the optimal value of the common and distinctive variables in terms of customer needs and design requirements. In modular product configuration, the product is designed from adding, substituting and/or removing functional modules.

The other stream of research in product family design is configurational product family design based on modular product architectures. Thus it is also called module-based product family design (Ulrich, 1995). The modular product configuration takes advantage of modular components. The product module involves

a one-to-one mapping from a functional requirement to the physical product feature. The product infrastructure with the specified decoupled interfaces between components allows each module to be changed independently. The various modules can be designed independently to satisfy customer's heterogeneous needs.

Flexible manufacturing for mass customization As the exponentially increased number of process varieties significantly challenges production planning and control of conventional manufacturing process (Tian et al. 2008; Terkaj et al. 2009), it is critical to have flexible manufacturing process in mass customization. From mass customization perspective, two approaches have been employed to improve the flexibility of a manufacturing process. Manufacturing process family is one important approach. The concept is to comprise a set of similar production process for various products to achieve economy of scale by utilizing the common components and standardized product platform designed within a product family. Thus, the manufacturer is able to configure the production process with quick response to product design change, by exploiting the similarity among the product variety and production process (Colledani et al. 2008).

Manufacturing for mass customization also relies on the availability of flexible manufacturing system. In addition, the system should be incorporated with the advent of modern Information and Computer Technology (ICT) as well as the flexible or reconfigurable manufacturing tools, to reduce the response time from designing a new product to the production ramp-up (Terkaj et al. 2009). For instance, such system can produce a new last for shoe production within 5 days since the customized shoe order is received. The system enables designers to change the CAD model easily with the limited additional cost. It is equally important that the flexibility in workforce and

production management systems are also key to achieve the seemingly conflicting goals of mass customization. With more educated human resource, decision to meet diverse requirements without increasing cost. Likewise, robust production control is essential to achieve on time delivery with complexity of materials management and logistics to realize mass customization.

Reconfigurable manufacturing system (RMS) Product variety can be very high under mass customization regime to cope with the changing product mix and demands. Manufacturing systems for mass customization need to well address the challenges. Reconfigurable manufacturing systems were proposed by Koren et al. (1998). An RMS is a system that is designed at the out-set for rapid changes in its structure and control in order to adjust its production capacity and functionality within a part family in response to sudden market changes. Configurations of the manufacturing system play an important role in impacting the performance of the systems (1999). It should be noted that RMS is different with flexible manufacturing system in the sense that RMS attempts to increase the manufacturing’s responsiveness to markets and customers and flexible manufacturing system aims at increase the variety of part produced. The flexibility of a RMS is confined within the product family.

Delaying Differentiation

To manage the high uncertainty and variety in manufacturing systems, delayed product differentiation or postponement strategy is widely used in industry. It refers that the manufacturing process makes a generic or family product at the beginning and differentiate into a specific end-product in the later stage when more information about the demand is obtained. Thus the point where the different products take on

their unique characteristics is postponed. The processes and assemblies are common up to the point of differentiation. Such delay reduces cost and improves responsiveness of the assembly systems (Lee and Tang, 1997; Ko and Hu, 2008). Figure 1(b) illustrates a configuration with differentiation.

Figure 1. Manufacturing system configuration: (a) mixed model assembly, (b) configuration with differentiation (Hu, 2013)

3. Personalization

Pine initiated the studies of mass customization and personalization and shaped them into a viable strategy. However in design field, the commonly agreed definition of personalization and customization has not been achieved yet, and some researchers use two terms interchangeably. We think that personalization attempts to increase products’ personal relevance to the individuals. In mass customization, customer participation is passive and limited. Customers make choices from a set of predefined offerings, and firms can autonomously produce and deliver products with little or even no customer participations. Personalization involves proactive customer participations. Customers collaborate closely with designers to develop products which satisfy their requirements. Personalization process is considered as consisting of three main stages (Murthi et al., 2003). In learning stage, firms collect customers’

data and study the data to understand the customers’ preferences and tastes. In matching stage, firms collaborate with customers and use the knowledge of customers to develop offerings that can best satisfy customers’ preference and to target these to appropriate market segment. In evaluation stage, firms evaluate the effectiveness of learning and matching efforts in providing meaningful personalization to the firm’s customers. In a nutshell, it is a customer co-creation process and can be considered as an extension of mass customization. This co-design process is enabled by an open product architecture (Koren et al., 2013), on-demand manufacturing systems, and responsive cyber-physical system involving user participation in design, product simulation/certification, manufacturing, supply and assembly processes that rapidly meet consumer needs and preferences.

Open architecture products Product personalization relies on an open product platform, allowing various modules to be integrated together. Comparing with product family design methodologies mass customization’s arena which consists of common modules and customized modules, a personalized product usually has one more personalized modules that allow customers to create and design. The module is integrated with common modules and customized modules in the open architecture. All these modules can be easily assembled and disassembled by applying the standard mechanical, electrical and informational interfaces. Product design may contain partial or all of the three types of modules due to the consideration of anticipated value, manufacturability and cost of the product. Product architecting aims at determining the modules structure of common, customizable and personalizable modules depending on cost and manufacturability (Berry, 2012).

On-demand manufacturing systems

To increase the responsiveness to customer demands, it is critical for manufacturing system to fabricating personalized product features and modules and assembling these modules with other manufacturer supplied modules flexibly. Additive manufacturing has been considered as an enabling technology towards personalization (Savitz, 2012). It can create 3D solid objects directly from a CAD model cost-effectively. In addition, a cost effective on-demand assembly system should be able to configure and reconfigure product in response to customers’ personalized designs.

Cyber-physical systems

Cyber-Physical Systems refer to engineered systems that are built from and depend upon the synergy of computational and physical components (NSF report, 2012). To support the distributed personalization design collaboration and on-demand manufacturing, it is necessary to integrate computational tools with the physical design and manufacturing systems. The development of new user interface methods and tools for personalized production will be critical to support the scalable user experience and collaborative, distributed design approaches. Considering users may share and view the design with likeminded people, we can leverage on existing cyber-social networking infrastructures to support these users. Methodology to identify emerging customer needs will be needed to address the potential business opportunity of new market and new product development.

4. Future direction of mass customization Defining customer requirement is the key to customization. Customer participation in the design process has shown to be the most promising way of getting the

requirements efficiently and effectively. Currently the whole process was mainly controlled by the designer and the product was finally manufactured and delivered by the producer. However, with the new interactive computing technology, it is possible for consumers to control and dominate the process in virtual environment. Thus, the role of the designer will be shifted to product platforms with sufficient supports to assist the process. It means that the product can be customized at any time when the consumer thinks it is necessary to do so, even after the product has been purchased. Such freedom would offer significant opportunities for consumers to dynamically adapt the product for their new needs as well as reflecting their identity and efficacy through the creative design and modifications, throughout the lifespan of the product. Customers become more connected. Products and services are increasingly knitted to a larger ecosystem of interacting objects. A product ecosystem can be considered as a dynamic unit that consists of all products and users, functioning together with its surrounding ambience, as well as their interactive relations and business processes. Looking at the whole sum of interacting objects and understanding the flow patterns of the ecosystem are for the future of mass customization.

Furthermore, technologies may change the delivery of the physical goods. For example, 3D printing technology may significantly stimulate the development of new MC. Recent reports in Economist demonstrate the potential of 3D printing and manufacturing changing the world. It is the manufacturing flexibility that constrained consumers within a limited freedom to customize. Given time, consumers will be able to really produce some physical components with machining systems. Thus, consumers can participate in the assembly of physical components. On the other hand, in order to achieve the production efficiency, the provider has to rely on product family concept to keep balance between the component commonality and variety. The

product modularity and platform will still be needed to navigate usage to describe their requirements. With technology, the consumer would feel free to produce any component, or even a whole product, as they want.

Looking forward, with the entry barrier reduced in both customer requirements acquisition at the front end and product delivery at the back end, we can thus extrapolate mass customization to open customization, along with the similar concepts as open system and open innovation. Open customization, still a working definition, is a paradigm that motivates people to participate, to create, to learn, to acquire, and to recover in providing goods and services to fulfill individual needs, not only products, but also the process of producing, with fair competition.

5. Conclusion and outlook

Mass customization defies the contradiction between mass and customization and aims to deliver products and services that best meet individual customers’ needs with near mass production efficiency. A novel and ambitious concept as it is, mass customization is also exposed to various conflicts, both strategically and operationally. Striving to serve diverse customer needs by precisely meeting customer needs is the main goal of production. It is important for being thieving in a competitive world but also reduce waste and delays. This should start with improving customer connection such as acquire customers requirement quickly and accurately. For design and manufacturing, connecting the entire product life cycle to achieve scale of economy across product families and generations are essential for cost effectiveness. Thus, commonality in product design, processes, delivery, service and sustainability is essential.

In summary, Mass Customization addresses basic issues of production systems across product design, marketing, manufacturing, sale, service to remanufacturing. It will continue to be a main thrust in both theory and practice.

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