In mold acceptance and measurement reports, terms like sensitivity, precision, accuracy, and resolution often get used interchangeably, but each points to something different. Sensitivity refers to how well a measurement system responds to small changes—for example, a CMM probe detecting displacement at the 0.5μm level. Resolution, by contrast, is the smallest scale increment the system can distinguish. The two are related but not equivalent: a probe can be highly sensitive without the display offering fine resolution. On the shop floor, this distinction matters when you're qualifying a new CMM or probing system for cavity insert work, because a probe that responds to sub-micron shifts still needs adequate resolution to report them meaningfully.
"Accuracy" is a loose term that, strictly speaking, should be split into accuracy and precision. Accuracy looks at the deviation between the measurement mean and the true value; precision looks at the scatter of repeated measurements. For mold cavity dimensional acceptance, if a report only says "accuracy ±0.01mm" without specifying whether that's accuracy or repeatability, communication breaks down fast—especially between the mold shop and the customer's QA team. In practice, a cavity dimension might hold ±0.01mm accuracy against the CAD model yet show 0.005mm repeatability across ten touches, and both numbers belong in a proper acceptance record alongside the gauge R&R study.
My rule on the floor: always state the term and the test method. When writing or reviewing a mold measurement report, spell out whether you mean accuracy against nominal, repeatability across multiple measurements, or resolution of the readout. That habit saves rework, avoids disputes at tool tryout, and keeps the acceptance conversation grounded in data both sides can verify. For more mold sourcing and inspection guidance, visit MoldSo at www.moldso.com.