To declare a workpiece or instrument non-compliant (scrap or rework), the measured value must fall outside the tolerance limits . The Rule:
ISO 14253-1:2017 Geometrical product specifications (GPS) — Inspection by measurement of workpieces and measuring equipmentPart 1: ISO - International Organization for Standardization ISO 14253-1 Decision Rules - HN Metrology Consulting
“You’ll learn to breathe through the yellow,” Anton said. But he didn’t teach her only to breathe. He taught her to read. INTERNATIONAL STANDARD ISO 14253 1.pdf
In precision manufacturing, measurement is never entirely absolute. Every measurement contains a degree of uncertainty. When validating whether a manufactured part meets its design specifications, this uncertainty can create a gray zone of doubt.
The most interesting aspect of this standard is how it fundamentally changes how we view a simple "Pass/Fail" result. To declare a workpiece or instrument non-compliant (scrap
ISO 14253-1:2017 provides general principles for the inspection by measurement of workpieces and measuring equipment. The standard covers:
The standard explicitly aligns with classical statistical hypothesis testing: He taught her to read
ISO 14253-1 solves this dilemma by introducing . The standard shifts the burden of proof depending on who is making the claim. 1. Proving Conformity (The Supplier's Duty)
Implementing the decision rules of ISO 14253-1 directly influences a company's bottom line and quality management system (QMS):
When a design engineer sets a tolerance limit, and a quality inspector measures the part, the measured value sits within a range of probability. If the measured value is close to the tolerance limit, the uncertainty interval may cross outside the allowable zone. This overlapping region is known as the . Without a standardized decision rule, a manufacturer might claim a part is good, while a customer's incoming inspection might reject it as bad. Decision Rules for Conformity and Non-Conformity
