GRR

Gage R & R calculation is made on basis : 3 Appraisers (A, B and C) measuring 3 times (trials) of 10 different parts.
  Part
Appraiser 1 2 3 4 5 6 7 8 9 10 Average
1 A trial 1
2 A trial 2
3 A trial 3
4 Average
5 Range
6 B trial 1
7 B trial 2
8 B trial 3
9 Average
10 Range
11 C trial 1
12 C trial 2
13 C trial 3
14 Average
15 Range
16 Part AVG Rp =
17 [RbarA+RbarB+RbarC]/[# of operators] Rdoublebar=
18 [MAX Xbar-MIN X bar]=XbarDIFF
19 [Rdoublebar X D4*] = UCLR
20 [Rdoublebar X D3*] = LCLR 0.00

*D4 = 3.27 for 2 trials and 2.58 for 3 trials;D3 = 0 for up to 7 trials. UCLR represent the limit of individual R's. Circle those that are beyond this limit. Identify the cause and correct. Repeat these readings using the same appraiser and unit as originally used or discard values and re-average and recompute R and the limiting value from the remaining observations.

GRR RESULT

Part No. and Name: ____________________ Gage Name:____________ # of trials = 3 Date: _____________
Characteristic: ________________________ Gage No:____________ # of parts = 10 Performed by: ______
Tolerance: Gage Type:______________ # of appraiser = 3
From data sheet: Rdoublebar = XbarDIFF = RP =

Some OEMs may allow to use the part tolerance as a divisor in stead of TV for finding % EV, % AV and % R & R. In such case you have to fill up the measured characteristic's tolerance in red input.

Measurement Unit Analysis % Process Variation
Repeatability - Equipment Variation (EV)
EV = Rdoublebar x K1 % EV = 100[EV/TV]
= divided by TV= %
  divided by tolerance= %
Reproducibility - Appraiser Variation (AV)
AV = SQRT[(XbarDIFF x K2)2- (EV2/nr)] % AV = 100[AV/TV]
= divided by TV= %
  divided by tolerance= %
Repeatability & Reproducibility (R & R)
R & R = SQRT[EV2 + AV2] % R&R = 100[R&R/TV]
= divided by TV= %
  divided by tolerance= %
Part Variation (PV)
PV = Rp x K3 % PV = 100[PV/TV]
= divided by TV= %
  divided by tolerance= %
Total Variation (TV) or Tolerance
TV = SQRT[R&R2 + PV2]
=


Created on 1/22/00
Ekkapol Pankam