The Engineering Design Process, Explained
Set direction, not decisions.
Know the path, not set it.
The organic process loosely defined as the engineering design process is a series of steps engineers take to refine the design and meet objectives. Today, let’s take a look at what constitutes the engineering design process.
Objectives
These are overall objectives and goals set for the design. What should the system do? This is often done by strategists, who set design targets and act as a line of communication between the stakeholders of the outcome. Without a clearly defined objective, designers will have a difficult time understanding what they’re trying to accomplish.
Establish Constraints
This step establishes requirements and hard constraints of the design. Often misunderstood as a determining function, this step serves to further narrow down on potential designs and will begin to address the high-level design of the system. Production/fabrication constraints, maximum allowable cost, maximum dimensions or weight, etc. are all design parameters that should be defined here.
Design
What many consider to be the whole of the engineering design process. Where the high-level design is debated, trade-offs discussed, and ultimately, the low-level design is designed and decided. This process can often involve CAD (Computer-Aided Design) to synthesize design and bring to life what before were mere blocks in the 3D modelling space or sketches on the whiteboard.
Analysis and Optimization
This part of the design process is very broad and encompasses much of what engineers do. While on one hand it can be running FEA (Fine Element Analysis) simulations to optimize material usage and machining time, on the other hand it can be analyzing empirical data to get the best performance out of motors and actuators. Data found during this process will inform the design of possible changes.
Evaluation
Testing is very much the name of the game here, and the iteration of the design directly leads to its evaluation. From prototyping to running the code, testing the design is critical to it being fully defined. Besides the viability of the design, testing design concepts can help designers understand the effort taken to produce their designs, which will impact the “effort vs reward” tradeoff directors will eventually have to take.
Presentation
At the end of optimization, the design must be presented. This can be in the form of a design review, where stakeholders will be present to review the design in a presentation given by the designers and directors of the project. In an industry setting, this will include time and cost projections and performance estimates to the customer. Design requirements from the beginning are expected to have been met at this stage unless modified midway.
The Trade-Off
I can predict with certainty that trade-offs will arise during the design process. From an engineer’s perspective, it’s all about optimization between performance, design requirements, cost, time, effort, and more. During these critical discussions, there are usually three main parties involved:
The designers will talk about the impact each decision will have on the overall design and performance. They will demonstrate what will happen and what they’ve come up with in terms of their recommendations.
The evaluators will talk about what they’ve seen in their prototyping results. Whether a certain design performed as expected, how much effort it took to execute a design, and what could be expected if the team decided to move forward with some concepts.
The strategists will talk about how each decision will impact the given overall goals. How, or if, objectives could be met with (or without) those features. They represent the “reward” side of the “effort vs reward” tradeoff.
In the end, we don’t make decisions, we set direction. The direction will adjust naturally as we continue to learn.