Iterate and Refine
The process of moving from constraints to architecture to interfaces and finally components is not linear but recursive. That is, we start at the system level and define major assemblies or modules. Then work through the same process to work towards individual component specification within an assembly. Unfortunately, decisions made in one assembly often affect the constraints or interfaces in another. The same is true even within an assembly where component specification affects other components. This leads to one of the major efforts of engineering design: Patching, Fixing and Satisficing.
Patching – Fixing – Satisficing
It is unlikely that a designer can develop a custom component or specifying a commercial off the shelf component in a single sitting. Rather, the parts and specification become more refined as the concept becomes less abstract.
Finding the gaps between component and assembly interfaces leads to refinements called patching. Patching is also used a means to implement needed secondary functionality. For example, a component may need attachments to a housing or other component. Defining the location, type and size of those attachment points is a patching process.
A major pain point in engineering design is discovering conflicts in the design specifications or requirements. These are often unexcepted and cost time and resources to solve. For example, when a material choice for the strength of a component leads to unacceptable total weight or stiffness. Resolving these conflicts is precisely what makes elegant and novel products. Sometimes there are ways to solve a conflict through innovative thinking. One powerful tool for this is call the “Theory of Inventive Problem Solving” or TRIZ.
Here is one implementation of TRIZ that you can try to solve a design conflict:
Finally, we aim to work through the detailed design stage with a goal of satisfying stakeholder needs. A well refined product is well suited for detailed optimization. However, in the development process, the designer’s goal should be to find satisfactory solutions. That is, when all stakeholder’s needs are satisfied.
