Optimizing Mechanical Restraint Forces in Non-Rigid Polymer Metrology under ISO 5459 Guidelines
Balancing restraint forces under ISO 5459 ensures accurate datum seating without distorting non-rigid polymer part features during coordinate metrology.
Gauge Repeatability and Reproducibility
Meaning
Statistical evaluations of the variation in a measurement system quantify the amount of measurement error introduced by the gages and the operators. Utilizing gauge repeatability and reproducibility analysis allows molders to determine if their dimensional inspection equipment is capable of reliably verifying close-tolerance plastic parts. High variation in the inspection process can lead to the false rejection of acceptable batches or the acceptance of defective parts.
Variable Partitioning
Total observed variation combines the actual part-to-part manufacturing variability and the measurement system error.
Operational Component
Repeatability represents the variation observed when one technician measures the same molded part multiple times using the same gauge. Reproducibility measures the variation that occurs when different technicians measure the same part under the same conditions. High reproducibility error points to a need for better training or more objective, automated inspection procedures.
System Approval
Metrology systems are deemed acceptable for production control when the study results show the system variation is below ten percent of the tolerance width. Values between ten and thirty percent might be tolerated depending on the criticality of the measurement and the cost of the gage. If the variation exceeds thirty percent, the measurement system must be redesigned or replaced before production starts.