Modular

A fundamental requirement of product standardisation is a simplification process to extract reusable modules from the non-modularised product. Modules allow the product to be broken down into either functional or assembly-based modules, the sum of which forms the product.

Even a complex product with millions of possible product variations can be managed using a small number of reusable modules. The keys to successful modularisation are the reusable interfaces which allow the assembly of modules and the rules that must be applied to ensure the correct use of modules.

Consider a Rubik’s cube; each cube can expose one of six sides.  The total number of possible configurations of the cube is 43,252,003,274,489,856,000 (according to the manufacturer). All these combinations are achievable with just twenty-seven six-sided cubes.

Using the same logic for product modularisation, however, unlike the Rubik’s cube rules dictate that modules can only be used in specific combinations and must meet given criteria.

Think of a modular product in the same way as another toy, Lego. The geometry of the Lego brick defines the possible interfaces of the brick. In this case, the brick is designed to interface from two sides. However, each Lego brick may expose different interfaces and rules of use.

Types of modularity

There are five main types of modularity [as defined by Pine – Mass Customisation, Ulrich & Tung – Fundamentals of product modularity]. Component sharing, component swapping, sectional modularity, cut-to-fit modularity and bus modularity.

Component sharing modularity

These share the same components across many modules. An example of this is Ford use the same engine in four different models of car. A clear advantage of doing this is that Ford only needs to develop one engine to produce four different products.

Component swapping modularity

The ability to swap different components across a range of modules is termed “component swapping”. An example of this is where customers are offered several different spectacle frames to fit an identical set of corrective lenses.

Sectional modularity

Modules can be combined using predefined interfaces (like Lego bricks) wherever the interface permits. In the following example, an HP laser printer can accept different paper trays.

Cut-to-fit modularity

Parametric dimensions or features can be changed to adapt the module to a new size or shape. For example, customer input drives the parametric height of a support frame.

Bus modularity

Bus modularity describes the bus or platform to which other modules must fit. For example, the Festo pneumatic control valves which are designed to fit modularly to a common base unit.

A modularised product may contain several different module types depending upon the product complexity. For example, the valve island above may use bus modularity for the valve interface but may also provide component sharing modularity for the push in fittings that connect the pipes to the valves.

Furthermore, the modular components may, in turn, be built up from further modular components. Therefore, the push in fittings may be simplified to be further modular components.

There are many motivations for creating modular products [Ref: Erixon G “Modular Function Deployment – A method of Product Modularisation.”]

• Reuse of parts, modules or sub-system
• Isolating a component for technological evolution
• Isolating a component for planned change
• Variance in the technical specification
• Variance in styling
• Production part commonality
• Production process commonality
• Quality by isolating tests
• Purchasing black box functionality
• Service and maintenance isolation or exchange
• Upgrading opportunities
• Recycling simplicity by limiting materials or finding reuse