Leveraging manufacturing knowledge is crucial to ensure designs are valid before committing time and resources.
For a design to be feasible to produce, it’s critical to focus on:
- Compatible materials and manufacturing process(es)
- Interfaces with other parts
- Expected/allowable tolerances
Awareness of these factors during design minimizes the number of iterations (and therefore time and costs) needed to produce a satisfactory final design.
Content List
Materials
Understanding the tradeoffs of materials is an often overlooked but crucial skill for mechanical designers. There is no one perfect material for every situation, some properties are mutually incompatible with others and may be desirable in one application while being troublesome in another. Thorough understanding of how and why materials behave is more in the realm of materials scientists, but a working knowledge of material families and how to use databases is expected of the modern mechanical engineer.
Processes
Production processes are what likely first come to mind when thinking of manufacturing, and for good reason. Choice of process is often among the most significant factors to a product’s cost, scalability, reliability, and many more metrics. Large production volume goals necessitate high volume processes such as injection molding, die-casting, and stamping. Delicate or complex materials may require less common processes like abrasive waterjet cutting or hand lay-up. In demanding applications (aerospace, defense, submersibles, etc), processes may even be invented to meet specific needs.
GD&T
(Geometric Dimensioning & Tolerancing)
GD&T is the modern drafting standard for unambiguous documentation of parts. In contrast to traditional tolerancing methods that give acceptable deviation as scalar values attached to measurements, GD&T applies tolerances as deviations from an ideal geometric shape each feature is attempting to achieve. This feature-based tolerancing scheme communicates part intent clearly and improves part acceptance rate through consistent inspection methods.
Traditional square tolerance zone (orange) and a geometric circular tolerance zone (blue) of equal size. Green dot is an element intended to be positioned on the black plus in center.
- For deviations in position along horizontal and vertical axes, the two systems behave identically.
- As the orientation of deviation approaches 45°, the traditional square zone allows more error (red lines), while the geometric circle enforces the same tolerance regardless of angle (yellow lines).
DFMA
(Design for Manufacturing and Assembly )
Design for Manufacturing and Assembly (DFMA) is a guiding philosophy used during the design phase in order to improve cost-effectiveness, reliability, ease of use, scalability, and simplicity of projects without compromising on performance. It involves leveraging manufacturing knowledge to avoid pitfalls. Examples of DFMA principles include minimizing part variety and quantity, sizing features based on standard tools and stock hardware, and designing parts so they only fit together in the intended way.
