Description :
Calibration of gages and instruments is a familiar activity whose purpose is to determine whether the gages in question return, on average, the same dimensions as the standards against which they are calibrated. This is required by ISO 9001. Calibration does not, however, ensure or even measure precision; the consistency with which the gages return the dimension in question. This is the purpose of measurement systems analysis (MSA), or gage reproducibility and repeatability (R&R).
Even if MSA is not required, it is highly advisable because lack of gage precision can allow the acceptance of borderline nonconforming parts, and reject parts that are borderline conforming. Lack of gage precision also makes statistical process control (SPC) charts less likely to detect process shifts.
Objective of the webinar :
Attendees will learn the rationale behind MSA, and also the generally accepted practices for performing it. This material includes:
Understanding the effect of gage variation on outgoing quality and statistical process control
Learn how to quantify gage variation components.
Repeatability is variation inherent to the gage and the measurement procedure.
Reproducibility is variation due to differences in how inspectors perform the measurement.
The total gage variation is a function of these two variation sources (square root of the sum of the two variances).
Apply the standard procedure for a gage repeatability and reproducibility study.
Learn potential remedies for non-capable gages including replication of measurements and guard banding.
Areas Covered in the Session :
Calibration (comparison of the gage's average measurement of a standard's dimension against the standard's actual dimension) and precision (the gage's ability to return the same measurement consistently) are two separate but important aspects of measurement system performance.
Gage R&R refers to repeatability (variation inherent to the gage, similar to common cause variation) and reproducibility (variation due to differences between inspectors).
Gage variation affects not only outgoing quality but also the power of SPC charts to detect process shifts. It does not however increase the false alarm risk for SPC charts.
The standard procedure for MSA includes minimum requirements for parts, inspectors, and replicated measurements. Readily available software such as Minitab and StatGraphics can then identify the variance components (repeatability and reproducibility) and overall gage variation, and also perform tests for the adequacy of the study.
Remedies exist for non-capable gages. Replication of measurements, if economically feasible, suppresses repeatability variation. Guard banding protects customers from nonconforming work at the expense of rejecting work that is borderline conforming.
A table of the d*2 factors (necessary for performance of the calculations in Excel) will be provided.
Who Will Benefit:
Manufacturing engineers
Quality engineers
Technicians
Inspectors with responsibility for inspections that involve quantitative measurements of parts.
About Speaker:
William A. Levinson, P.E., FASQ, CFPIM, is the owner of Levinson Productivity Systems PC. He holds professional certifications from the American Society for Quality, APICS, and Society of Manufacturing Engineers.
Event URL: http://bit.ly/2A6cfWt
