Modular Product Architecture

This paper presents an approach to architecting a family of products that share inter-changeable modules. Rather than a fixed product platform upon which derivative products are created through substitution of various add-on modules, the approach here permits the platform itself to be one of several possible sizes or types. Thus, the system is a collection of modules, each of which can be one of several types. We begin by developing function structures of each product in the portfolio, where each embodies a specific physical principle underlying the common technology. Different function structure systems can be used for each physical principle under consideration. These function structures are then compared to determine common and unique modules. Product modularity rules (i.e. dominant flow, branching, and conversion) are then applied to determine further possible modules. Application of any consistent set of modularity rules defines a feasible portfolio architecture. Each portfolio architecture is represented using a modularity matrix of functions versus products, with shared/unique function levels indicated in the matrix. Possible product modules are indicated with boxes while possible portfolio modules are indicated with shading. This method provides a systematic approach to generating possible portfolio architectures and serves as a communication aid for design team deliberations. INTRODUCTION Determining product architecture is one of the key activities of any industrial product development activity. Volkswagen claims to save $1.7 billion annually on development and production costs through effective product architecture (Bremner, 1999). Volkswagen is able to take advantage of platform and component commonality by sharing between its four major brands, namely VW, Audi, Skoda, and Seat. These different automobiles share car platforms, which in Volkswagen’s case includes front axles, rear axles, front ends, rear ends, exhaust systems, brake systems, and numerous other elements (Bremner, 1999). However, Volkswagen also claims that all vehicles on this shared common platform can be effectively differentiated in the eyes of the customer. Interestingly, Ford Motor Company has similar shared platform ambitions within its new Generic Architecture Process program. However, Ford defines its platform, which will be shared between several car models, to consist of common welding lines, suspension systems, and drivetrains (Bremner, 1999). Ford has similar expectations of large monetary savings in development and production costs while maintaining the ability to effectively differentiate the platformed cars in price and performance. Suprisingly, Volkswagen and Ford's definitions as to what constitutes a platform are vastly different. This example highlights that the product architecting process, despite being a key determining factor in both cost savings and in the ability to offer product variety, is not well understood. System engineering and architecting remains an activity relegated to heuristics. Such activities are often only completed by experienced systems engineers who have gained an understanding of the various objectives that must be considered when architecting a product line. In this paper, we will develop a systematic methodology to architecting a product portfolio.