Conclusiones:

As discussed in Chapter 1, products in the automotive industry are platform based. Most manufacturers carry over a significant number of components between product generations and between different brands (models), in order to reduce the design effort and the risk associated with the product development.

In the literature, product platforms are described slightly differently depending on the product application. Meyer (1997) defines the product platform as a set of common components, modules, or parts from which a stream of derivative products can be efficiently developed and launched. Muffatto and Roveda (2002) adds another variant to Meyer’s definition and assumes that a product platform is “a set of subsystems and interfaces intentionally planned and

developed to form a common structure from which a stream of derivative products can be

efficiently developed and produced”. This definition can be extended according to Hohnen et

24 The several platform definitions show that there is significant variation in the level of concretisation, ranging from sharing specific components to common approaches to more general subsystems from which products can be developed. An example from automotive platforms where different products (brands) share the same module is shown in Figure 2-5. This is an example of a specific suspension module which can be used for different products with only few component additions.

Figure 2-5 Example of a common module shared by different products

Product platforms are generally considered through component/part commonality, but some definitions do also include other aspects such as technology, people and relationships. Production aspects such as technology, process, operations and resources may also set the foundation for identifying and designing platforms. This type of platform is referred to as a production platform (Asbjørn and Ditlev 2011)

Platforms are generally described to be of one of either two kinds: (1) Module-based platforms are characterised by sets of components being clustered into interchangeable modules that

together form the product. The module-based platform can either be integral, where functions are shared by several modules, or modular, where each function is delivered by a separate module. (2) The second platform approach is the scalable platform. This platform supports adaptation by the stretching or shrinking of the product instances following variations in design variables (Jiao et al. (2007)). A platform approach is shown to be an enabler for efficient customisation, reuse and production standardisation.

A platform has implications like the use of common manufacturing processes, as well as technology and knowledge shared by multiple products in a family. Therefore, components in a product platform need to be designed in such a way that they can contribute to satisfying the requirements placed on all the products which are designed to be based on the platform. Several works in the literature consider the product platform as the baseline for product family development. Product families are a way to increase the product variety while contraining the product development and manufacturing effort. Simpson et al. (2001) defines a product family as a group of related products that share common features, components and subsystems; and satisfy a variety of market niches. A product family comprises a set of variables, features or components that remain constant in product platform and others that vary from product to product. Krishnan and Ulrich (2001) defines product variety as the diversity of products that a production system provides to the marketplace. Product families are based on the idea of reuse. Therefore, if the customer needs are anticipated well in advance, modules and variants can be reused.

Martin and Ishii (2002) distinguishes between two types of variety when developing the architecture of a product range: variety within the current product line being designed and variety across future generations of the product. It refers to variety in the current product being designed as “spatial” variety, and the variety across generations as “generational variety”. Du et

26 variety”. Whilst functional variety mostly relates to customer satisfaction, technical variety is relevant to manufacturability and costs.

The crucial step in platform design is modularisation. Otto and Simpson (2014) gives an extensive overview of modularisation methods. Product platform design can be separated from the initial phase of platform planning and the subsequent phase of platform implementation. Schuh et al. (2011) provides a holistic approach for the creation of modular product platforms integrating the planning, design and implementation in one process model. The aspect of changeability in the lifecycle perspective of a product platform is still a deficiency in current approaches. Suh et al. (2008) addresses this issue with his work on flexible product platforms. This approach however lacks the focus on functions and ranges of function requirements that usually have to be fulfilled by a modular product platform. It is necessary to consider functions and ranges of function especially when designing modular product platforms, for mechatronic systems for example.

In the automotive industry, products are generally designed incrementally. New products are created by changing certain design parameters of the product. Typically, these changes enable an increase in performance or an adaptation to market-specific requirements.