<aside> đźš© Detailed design is where you start ascribing size, shape, and material to parts and assemblies.
</aside>
Detailing a design is the last step in the design process before entering the prototype and test phase of product development. Given a single “best” Design Concept, the Detailed Design stage involves establishing size, shape, material, and other characteristics, to parts and assemblies.
The results of Detailed Design are (a) a Working Set of Drawings that can be used to manufacture parts and assemble them into a whole intervention, (b) documentation justifying all decisions made during Detailed Design, and (c) supporting documentation regarding installation, maintenance, use, and decommissioning of the intervention.
In this course, only items (a) and (b) are required.
The Detailed Design is documented in the Product Design Specification.
In “real-life” complex products (cars, boats, planes, etc.) each system can be treated like a separate design problem, and we could start a new design process for each of them. For example, in designing a car, one might start with designing the overall systems of a car, but then treat the design of the engine as a separate problem, and apply all the same methods to it. We can do this because of the recursion built into our systems engineering approach. The System Interfaces between the engine and the rest of the car are of the same type as the interfaces between the car and the rest of the world.
In the design of automobiles, one can expect three or four levels of systems; in an airplane there can be six or seven.
However, in an academic setting where there is so little time to do this kind of recursive design, we must limit ourselves to only two levels of systems. The projects have been chosen specifically to encourage design teams to have only one set of subsystems in their design below the product itself – this is not a requirement, of course, because there is no single “right” answer in design.
One generally knows that there are no subsystems because one can easily envision a single component, be it a bolt, a lug, a motor, a hydraulic cylinder, and so on, to fill in the role of a systems component.
Note that the boundary of the system on the outside is the boundary between your product as a whole and the rest of the world. There can also be an “inner” boundary at the lowest level of your product's components. For example, if your company is designing a refrigerator, it will likely not also design the electric motor that the refrigerator will use. That is, your company designs refrigerators, not motors; you will likely just “spec” an appropriate motor that you found in a catalog of some sort. This means that you are not responsible for the design of the motor, only for selecting the right one. If you are not responsible for the motor, then the boundary between your product system ends at the motor.
Here is another example. Consider the design of a stapler for home use. We might easily envision the following systems:
The most important point here is this: the systems are distinct and separate, but the physical parts that implement the systems may be common to many systems. For example, in the typical stapler, the guide that carries the staples internally is a single piece of metal, but it is a part of the structural system because it carries many of the loads in the stapler, as well as part of the storage system because it holds the staples.