Setting tolerances too tight drives up manufacturing costs exponentially. Setting them too loose results in components that fail to assemble. Mechanical engineers must master Geometric Dimensioning and Tolerancing (GD&T) to find the sweet spot.
GD&T defines the allowable variation of geometric features relative to datum references. Instead of linear dimensions, it focuses on runout, concentricity, and position.
"Tolerancing is a balance of function and cost. A great designer tolerances components as loosely as the math allows."
Tolerance Stack-Up Analysis
When multiple parts assemble, their variations add up. Worst-case stack-up analysis ensures parts fit even if every single feature is at its maximum tolerance limit. Utilizing statistical analysis (like RSS) predicts assembly success rates in bulk production.
Design for Machining
Understanding CNC capabilities prevents drawing features that require EDM or custom cutting tools. Designing parts that can be machined in a single setup ensures precision alignments are held easily without manual fixtures.