In the context of machine tools and manufacturing, discrimination is the ability of an instrument or machine to detect and respond to the smallest possible change in a physical quantity.
It is often used interchangeably with resolution.
Key Characteristics
- Smallest Increment: It represents the smallest change in input that produces a detectable change in output.
- Scale Limits: On a manual tool (like a ruler), discrimination is the smallest graduation on the scale.
- Digital Tools: On a CNC or digital caliper, it is the last decimal digit shown on the display.
- Sensitivity: A tool with “high discrimination” can distinguish between very fine differences in size or position.
In Inspection (Metrology)
📌 The 10-to-1 Rule: In quality control, your inspection tool should have a discrimination (resolution) that is at least 10 times finer than the tolerance you are measuring.
- If your part tolerance is ±0.001″, your tool should discriminate to 0.0001″.