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Napino Auto & Electronics Ltd. TITLE:

PROCEDURE

MEASUREMENT SYSTEM ANALYSIS 1.0

DOCUMENT/ISSUE SECTION PAGE NO. REVISION NO. DATE SIGNATURE

QMP- 762 -1 of 3 01 28.05.2013 CMD

PURPOSE To document the process of evaluating the quality of measurement systems and to establish repeatability and reproducibility of the instrument and appraiser.

2.0

SCOPE

2.1

All Instruments / Gauges being used to verify significant (key) characteristics of the product.

2.2

Person usually involved in verification of such characteristics.

3.0

DEFINITIONS

Re

4.0

MSA

Measurement System Analysis.

GR & R

Gauge Repeatability and Reproducibility.

Appraiser

Person usually using the instrument for product verification.

Repeatability

Variation in measurements obtained with one measuring instrument used by one appraiser measuring one characteristic several times on same part.

Reproducibility

Variation in the averages of measurements, made by different appraisers using the same instrument when measuring same characteristic on the same part.

Measuring System

Appraiser, Gauge, Part- Characteristics and Measuring process considered for obtaining measurements.

Bias

Bias is the difference between the observed value and reference value.

Linearity

The slope of the regression line that best fits the bias average versus reference values multiplied by the process variation of the part index that can represent the linearity of the gauge.

REFERENCES QMP 761

Calibration Procedure

5.0

PROCEDURE

5.1

Head QA shall identify the need for conducting MSA and draw out a plan listing:

F 0501 / 00

Napino Auto & Electronics Ltd. TITLE:

PROCEDURE

MEASUREMENT SYSTEM ANALYSIS 5.2

DOCUMENT/ISSUE SECTION PAGE NO. REVISION NO. DATE SIGNATURE

QMP- 762 -2 of 3 01 28.05.2013 CMD

MSA Process to be followed. Instrument to be used. Scheduled date of study.

For variable data, Average and Range method shall be used for the study. Observations shall be recorded on the Data Sheet by the observer. He shall make all arrangements for the study.

5.2.1 Three appraisers and minimum ten parts duly numbered shall be used for the study. 5.2.2 The Instrument used shall have valid calibration and duly identified as per procedure. (QMP 761.) 5.2.3 Part numbers shall not be discernible by the appraisers. The observer alone shall be able to identify the parts individually by the numbering system devised by him and Head QA. 5.2.4 The appraisers shall not have access to each others observations and their previous trial records. 5.2.5 The observer shall ensure that observations are taken on parts randomly picked up covering entire range of achievable specifications. 5.2.6 After recording observations, the observer shall calculate averages and ranges as required and work out R, X diff Rp from the observations. 5.2.7 The observer shall calculate EV, AV, R&R, PV and TV and also %EV, %AV, %R&R and %PV on the Gauge R&R Report Sheet. 5.2.8 Incase of approved computer program availability, steps 5.2.6,5.2.7 shall be done in the computer. After feeding the observation, a printout on acceptability shall be taken out by the Head - QA. 5.3

ANALYSIS

5.3.1 Acceptance of gauge R&R shall be as follows -

NDC (No. of distinct categories) > 5

-

% R&R Under 10 % Between 10 - 30 %

F 0501 / 00

- Measurement System Acceptable - Measurement System may be accepted based on Importance of application & cost of gauge & repairs.

Napino Auto & Electronics Ltd. TITLE:

PROCEDURE

MEASUREMENT SYSTEM ANALYSIS

DOCUMENT/ISSUE SECTION PAGE NO. REVISION NO. DATE SIGNATURE

QMP- 762 -3 of 3 01 28.05.2013 CMD

(Gauge Bias, repeatability, stability and linearity shall be checked for acceptability) -

Over 30 %

- Not acceptable, needs improvements.

*

If repeatability is large as compared to reproducibility - The Gauge / Instrument needs maintenance or redesign.

*

If reproducibility is large as compared to repeatability then appraisers need to be trained further. The analysis shall be approved by head Q.A. directing follow-up action if any.

5.4

ATTRIBUTE GAUGES

5.4.1 For attribute gauges, two appraisers and one observer shall be used and records made by the observer on Format F 1103 specifying Good (G), Not Good (NG). 5.4.2 Twenty parts shall be selected for the study ensuring that five parts close to lower specification and five parts close to upper specification (Gray area) and remaining few should lie outside lower and higher acceptable limits. All parts shall be numbered for identification by the observer involved in the study. 5.4.3 No Appraiser shall have access to his or other appraiser’s previous similar trial results. 5.4.4 Each appraiser shall conduct two trials per part randomly without having access to its identification number. 5.5

ANALYSIS The gauge is acceptable if all measurement decisions or results (four per part) agree.

5.5.1 If measurement decisions do not agree than the gauge must be improved and reevaluated as per procedure. 6.0

DOCUMENTATION F 1101

Data Sheet for Average & Range

F 1102

Gauge R&R Report Sheet

F 1103

Data Sheet for Attribute Gauges MSA Plan

F 0501 / 00