A hinge that feels the same on day 1,000
Apple · Tolerance analysis
2023
Led the tolerance analysis for a hinge whose opening force had to stay within a narrow band across every unit and its whole life.
What I did
• Built the stack-up model (RSS and worst case) and found two contributors driving 70% of the variation • Changed the datum scheme so they were measured from the same feature • Wrote the inspection plan the factory used for incoming parts
Result
Variation in opening force halved; no tolerance-related rework at launch.
Details are described at the level of public product information. (In this fictional example, everything is invented.)