I recently co-authored an article with my colleague James R. Roll about the importance of using GD&T for detecting bad design before production. The article, “Avoiding Design Problems With Geometric Dimensioning and Tolerancing,” was published a few weeks ago in Machine Design magazine.

Here’s a short excerpt:

machine-design.jpgDatum selection is the best place to start when managing variation during the PDP. A robust datum scheme uses datums that best prevent the parts from moving out of position, minimizes the number of items in a tolerance stack, is well controlled within the part (location tolerances and rigid features) and is shared by as many manufacturing processes as possible.

The datum scheme is largely driven by the product-build strategy and system requirements, thus it is important to consider the effect of datum selection early in a PDP (requirements and system design phases). The design-and-build strategy defined at this stage will have the largest effect on product quality with the least cost. Mistakes made at this stage will be expensive to fix at later stages, if they can be corrected at all.

Please read the full article at the magazine’s website here and let me know what you think. I look forward to your feedback.