What is Embodiment design?
Embodiment design is one of the main stages of the product design process in which, the main engineering product design concept is developed as per the product design specification (PDS) and economic criteria to a stage where subsequent detailed design can lead directly into production.
Embodiment product design phase of an engineering product design follows the concept design phase where various concepts are generated and evaluated to produce a single final concept. (Figure 1)
In some sections of literature, this phase is also referred to as preliminary design or system-level design. The term Embodiment design is coined by Pahl and Beitz (2006) and adopted mostly by modern European engineering product design managers. Concept design followed by Embodiment design and detailed design is more suitable for an engineering product design hence this article uses these terms although there are various product design process models.
The output from the Concept design might vary from simple block diagrams (figure 2) to very early prototypes concepts. It depends on what type of product development the company is pursuing.
Embodiment design phases
Embodiment design is a complex process as many design activities must be simultaneously performed, some of the design activities need to be repeated several times with changing data and any changes in one section will influence another section of the design.
Every engineering product design is different and adds this to the above challenges, precisely the reason why it’s very difficult to have strict set-out plans for the embodiment design phase.
So, at the embodiment stage of new product development, an abstract design concept will get moulded into a system or product that works and can be manufactured within the allocated unit cost.
Embodiment design phase activities can be divided into three sections or phases (figure 3).
- Product architecture
- Design configuration
- Parametric design
Product architecture, also referred to as System-level design is, outlining and allocating physical components or entities to the function of a product. Physical elements are defined and arranged to satisfy the overall product requirement specification and are usually called modules.
Product architecture could start with very simple block diagrams as shown in figure 4 or could be well thought out ongoing family of products.
System-level design is defined by how each subcomponent or modules interact with each other in a product level and the function of each subcomponent. Product architecture is vital to any product development as it would impact the product evaluation and the cost of the product.
Product architecture can fall into two categories or styles. Modular and Integral.
In modular design, overall product purpose or system-level function is subdivided into smaller single functions or individual operations and allocated to single parts or sub-assemblies called modules. These modules are treated as individual components and have well defined electrical or mechanical interface. These are then interfaced together to form the complete product to perform its complete function. Engineering products with modular architecture are more common than integral designs.
Integral product architecture is where the functions of the engineering product are carried out by a combination of parts which are not organized in a structured manner. Hence, the functional implementation is achieved by one or very few modules where components perform multiple functions.
Integral system-level design is often preferred when weight, shape, size & cost constraints affect and undermines the performance of the product. Design for manufacture and assembly which emphasizes minimises parts count also another strong driver of integral product architecture product designs. Generally, integral engineering products have a very high function to components ratio, meaning the product can perform multiple functions using the same components differently.
In design configuration, shape and general dimensions or sizes are established to the components that are defined in product architecture. It is largely depended on the three-dimensional constraints that define the envelope in which the product operates and the product architecture. This would be a preliminary selection of material, manufacturing process, modelling, sizing of parts etc.
Design configuration, sometimes referred to as form, develops from its function and strongly depends on available material and its manufacturing techniques.
The design configuration phase should involve the following steps;
- TRS or Product design specification (PDS) review
- Identify and define the space constraints
- Identify and define the interfaces and connections between the components
- Maintain functional independence of an assembly or the components to ensure that changes should affect only a single function
- Identify and eliminate or reduce parts by either removing it or combing few parts together
The main objective of the Parametric design is to allocate values to design variables to produce the best possible product design or functional component by considering both the technical and economical requirement. This aspect of the design is much more analytical than conceptual or design configuration.
Design variable is an attribute of a part whose value is under the control of the designer – these are typically dimension, tolerance, material, surface finish, heat treatment etc.
The main objective of parametric design is to set values for the design variables that will produce the best possible design considering both the performance and cost. Parametric design is also about setting the dimensions and tolerances to maximize quality and performance and minimize the cost.
Steps would vary vastly depending on the nature of the product. But, for physical engineering products, product development could be divided into the following five steps.
- Parametric design problem formulation
- Alternative design generations
- Alternative design analysis
- Analysis of results evaluation
- Refining and optimisation