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Apr 21, 2022 at 06:30 AM

How can I setup in SAP QM Sampling according to ISO SANS 3951-1 using MSSD?

129 Views Last edit Apr 22, 2022 at 06:44 AM 2 rev

Can you please assist me in setting up the following in SAP - MSSD (Maximum sample standard deviation)

EXAMPLE (MSSD) The minimum temperature of operation for a certain device is specified as 60 °C and the maximum temperature as 70 °C. Production is in inspection lots of 96 items. Inspection level II, normal inspection, with AQL = 1,5 %, is to be used. From Table A.1 (According to SANS Table ), the sample-size code letter is found to be F; from Table A.2 (According to SANS Table) it is seen that a sample of 13 is

required, and from Table D.1 (According to SANS Table) that the value of fs for the MSSD under normal inspection is 0,274. Suppose the measurements obtained are as follows:

65,5 °C; 60,0 °C; 65,2 °C; 61,7 °C; 69,0 °C; 67,1 °C; 60,0 °C; 66,4 °C; 62,8 °C; 68,0 °C; 63,4 °C; 60,7 °C; 65,8 °C;

compliance with the acceptability criterion is to be determined.

Information needed Value obtained

Sample size: n13

1 n

nSample mean: x = å x j

j =1

Sample standard deviation: s =

64,28 °C

2,86 °C

(See J.1.2, Annex J.) (According to SANS)

Upper specification limit: U70,0 °C

Lower specification limit: L60,0 °C

Value of fs for MSSD (smax) (Table D.1) 0,274

smax = (U - L)fs 2,74 °C

As the value of s exceeds smax the lot may immediately be judged unacceptable.

NOTE This lot is not acceptable even though all inspected items in the sample are within the specification limits.