gr&r + project tree diagram.pdf
DESCRIPTION
GR&R + Project Tree Diagram.pdfTRANSCRIPT
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Addresses what percent of the Total Variation is taken up by Measurement Error.
Best case/new equipment:
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27
GaugeR&R Graphical Output
Perc
ent
Part-to-PartReprodRepeatGage R&R
100
50
0
% Contribution
% Study Var
% Tolerance
Sam
ple
Range
0.10
0.05
0.00
_R=0.0383
UCL=0.1252
LCL=0
1 2 3
Sam
ple
Mean
1.00
0.75
0.50
__X=0.8075UCL=0.8796
LCL=0.7354
1 2 3
PartID
10987654321
1.00
0.75
0.50
OperatorID
321
1.00
0.75
0.50
PartID
Avera
ge
10 9 8 7 6 5 4 3 2 1
1.00
0.75
0.50
1
2
3
OperatorID
Gage name:
Date of study :
Reported by :
Tolerance:
M isc:
Components of Variation
R Chart by OperatorID
Xbar Chart by OperatorID
Measure by PartID
Measure by OperatorID
OperatorID * PartID Interaction
Gage R&R (ANOVA) for Measure
Minitab produces this graphical output. Interpretation of this graph will help us target improvement efforts.
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28
GaugeR&R Graphical Output 1
Perc
ent
Part-to-PartReprodRepeatGage R&R
100
50
0
% Contribution
% Study Var
% Tolerance
Sam
ple
Range
0.10
0.05
0.00
_R=0.0383
UCL=0.1252
LCL=0
1 2 3
Sam
ple
Mean
1.00
0.75
0.50
__X=0.8075UCL=0.8796
LCL=0.7354
1 2 3
PartID
10987654321
1.00
0.75
0.50
OperatorID
321
1.00
0.75
0.50
PartID
Avera
ge
10 9 8 7 6 5 4 3 2 1
1.00
0.75
0.50
1
2
3
OperatorID
Gage name:
Date of study :
Reported by :
Tolerance:
M isc:
Components of Variation
R Chart by OperatorID
Xbar Chart by OperatorID
Measure by PartID
Measure by OperatorID
OperatorID * PartID Interaction
Gage R&R (ANOVA) for Measure
This graph has 4 groups of bars (values of each bar are estimated by looking at the Y axis):
Gage R&R group: The green bar indicates the %R&R and the blue indicates the precision to tolerance ratio. We can ignore the red bar on all the graphs.
Repeat group: Green displays the percentage of variation in our results caused by repeatability. Blue displays the amount of tolerance taken up by repeatability. If this is high then calibration is
often required.
Reprod group: Green displays the percentage of variation in our measurements caused by reproducibility. Blue displays the amount of tolerance taken up by repeatability. If this group is high
then operator training might be a required action.
Part-to-Part group: We should expect this group of bars to be much higher than the other groups. This would indicate that most of the variation observed is in the parts themselves and not in the way
they have been measured.
Memory Aid: Green Belts use the Green Bar to assess MS.
If we do not input a tolerance then the blue bar will not be displayed.
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29
GaugeR&R Graphical Output 2
Perc
ent
Part-to-PartReprodRepeatGage R&R
100
50
0
% Contribution
% Study Var
% Tolerance
Sam
ple
Range
0.10
0.05
0.00
_R=0.0383
UCL=0.1252
LCL=0
1 2 3
Sam
ple
Mean
1.00
0.75
0.50
__X=0.8075UCL=0.8796
LCL=0.7354
1 2 3
PartID
10987654321
1.00
0.75
0.50
OperatorID
321
1.00
0.75
0.50
PartID
Avera
ge
10 9 8 7 6 5 4 3 2 1
1.00
0.75
0.50
1
2
3
OperatorID
Gage name:
Date of study :
Reported by :
Tolerance:
M isc:
Components of Variation
R Chart by OperatorID
Xbar Chart by OperatorID
Measure by PartID
Measure by OperatorID
OperatorID * PartID Interaction
Gage R&R (ANOVA) for Measure
This graph displays the range of the measurements for each part grouped by each operator.
The points along the bottom red line (LCL) show where an operator has recorded the same measurement for a part twice i.e. zero range.
As an example the 4th point from the left is at 0.10 which tells us that the 2 measurements recorded by operator 1 for part 4 were different by 0.10
This graph breaks down the repeatability by operator. This example indicates that operator 3 is contributing the lowest amount to the variation caused by repeatability.
part 10 operator 3
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30
GaugeR&R Graphical Output 3
Perc
ent
Part-to-PartReprodRepeatGage R&R
100
50
0
% Contribution
% Study Var
% Tolerance
Sam
ple
Range
0.10
0.05
0.00
_R=0.0383
UCL=0.1252
LCL=0
1 2 3
Sam
ple
Mean
1.00
0.75
0.50
__X=0.8075UCL=0.8796
LCL=0.7354
1 2 3
PartID
10987654321
1.00
0.75
0.50
OperatorID
321
1.00
0.75
0.50
PartID
Avera
ge
10 9 8 7 6 5 4 3 2 1
1.00
0.75
0.50
1
2
3
OperatorID
Gage name:
Date of study :
Reported by :
Tolerance:
M isc:
Components of Variation
R Chart by OperatorID
Xbar Chart by OperatorID
Measure by PartID
Measure by OperatorID
OperatorID * PartID Interaction
Gage R&R (ANOVA) for Measure
The points plotted on this graph are the mean results recorded for each part by each operator.
The green line shows the mean result of all measurements.
As a rule of thumb this graph should have about 80% of points outside the red lines (control limits). The points outside the limits indicate that the system can differentiate parts.
If less than 80% are outside the red lines then the GR&R% will be poor.
Control limits will be discussed in the control chart module.
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31
GaugeR&R Graphical Output 4
Perc
ent
Part-to-PartReprodRepeatGage R&R
100
50
0
% Contribution
% Study Var
% Tolerance
Sam
ple
Range
0.10
0.05
0.00
_R=0.0383
UCL=0.1252
LCL=0
1 2 3
Sam
ple
Mean
1.00
0.75
0.50
__X=0.8075UCL=0.8796
LCL=0.7354
1 2 3
PartID
10987654321
1.00
0.75
0.50
OperatorID
321
1.00
0.75
0.50
PartID
Avera
ge
10 9 8 7 6 5 4 3 2 1
1.00
0.75
0.50
1
2
3
OperatorID
Gage name:
Date of study :
Reported by :
Tolerance:
M isc:
Components of Variation
R Chart by OperatorID
Xbar Chart by OperatorID
Measure by PartID
Measure by OperatorID
OperatorID * PartID Interaction
Gage R&R (ANOVA) for Measure
This graph displays the results of all operators by part.
From this graph it can be seen that the operators seem to be having particular problems measuring part 10. The variation in results is higher than for any other part.
As part of our measurement system improvement we might want to find out what it is about part 10 that is so difficult to measure.
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32
GaugeR&R Graphical Output 5
Perc
ent
Part-to-PartReprodRepeatGage R&R
100
50
0
% Contribution
% Study Var
% Tolerance
Sam
ple
Range
0.10
0.05
0.00
_R=0.0383
UCL=0.1252
LCL=0
1 2 3
Sam
ple
Mean
1.00
0.75
0.50
__X=0.8075UCL=0.8796
LCL=0.7354
1 2 3
PartID
10987654321
1.00
0.75
0.50
OperatorID
321
1.00
0.75
0.50
PartID
Avera
ge
10 9 8 7 6 5 4 3 2 1
1.00
0.75
0.50
1
2
3
OperatorID
Gage name:
Date of study :
Reported by :
Tolerance:
M isc:
Components of Variation
R Chart by OperatorID
Xbar Chart by OperatorID
Measure by PartID
Measure by OperatorID
OperatorID * PartID Interaction
Gage R&R (ANOVA) for Measure
This graph displays all measurements grouped by operator.
The variation appears to be much the same for all operators.
Operator 2 has a slightly lower mean result than the other operators. Operator 2 is measuring parts slightly lower on average than operators 1 and 3.
You might want to find out why i.e. is operator 2 using the tool correctly?
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33
GaugeR&R Graphical Output 6
Perc
ent
Part-to-PartReprodRepeatGage R&R
100
50
0
% Contribution
% Study Var
% Tolerance
Sam
ple
Range
0.10
0.05
0.00
_R=0.0383
UCL=0.1252
LCL=0
1 2 3
Sam
ple
Mean
1.00
0.75
0.50
__X=0.8075UCL=0.8796
LCL=0.7354
1 2 3
PartID
10987654321
1.00
0.75
0.50
OperatorID
321
1.00
0.75
0.50
PartID
Avera
ge
10 9 8 7 6 5 4 3 2 1
1.00
0.75
0.50
1
2
3
OperatorID
Gage name:
Date of study :
Reported by :
Tolerance:
M isc:
Components of Variation
R Chart by OperatorID
Xbar Chart by OperatorID
Measure by PartID
Measure by OperatorID
OperatorID * PartID Interaction
Gage R&R (ANOVA) for Measure
This graph shows the mean result for each part by each operator.
Look for differences in the mean readings of each part.
Differences may be caused by particular parts i.e. part 10 being difficult to measure.
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GaugeR&R Session Window Output
Perc
ent
Part-to-PartReprodRepeatGage R&R
100
50
0
% Contribution
% Study Var
% Tolerance
Sam
ple
Range
0.10
0.05
0.00
_R=0.0383
UCL=0.1252
LCL=0
1 2 3
Sam
ple
Mean
1.00
0.75
0.50
__X=0.8075UCL=0.8796
LCL=0.7354
1 2 3
PartID
10987654321
1.00
0.75
0.50
OperatorID
321
1.00
0.75
0.50
PartID
Avera
ge
10 9 8 7 6 5 4 3 2 1
1.00
0.75
0.50
1
2
3
OperatorID
Gage name:
Date of study :
Reported by :
Tolerance:
M isc:
Components of Variation
R Chart by OperatorID
Xbar Chart by OperatorID
Measure by PartID
Measure by OperatorID
OperatorID * PartID Interaction
Gage R&R (ANOVA) for Measure
The exact %R&R is difficult to read accurately if the graph alone is used.
The session window gives us the values that we require to focus on measurement system improvement.
The key points that are of interest to a Green Belt are:
The ANOVA table P values.
The lower block of data.
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GaugeR&R Session Window Output (cont)
The meaning of the ANOVA table P values will be more understood after the hypothesis testing module.
For now it is enough to remember that if the P value is below 0.05 then the corresponding variation source has a significant effect on the overall observed variation.
All of the P values in this case are below 0.05. We can say that all the variation caused by factors is significant.
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Minitab, Gauge Run Chart:
Generates a run chart of measurements by operator and part.
Allows us to visualize
repeatability and reproducibility within and between operator and part.
The center line is the overall average of the parts OperatorID
Me
asure
Mean
1.0
0.8
0.6
0.4
1.0
0.8
0.6
0.4
Mean
1 2 3 4 5
6 7 8 9 10
1
2
3
O peratorID
Gage name:
Date of study :
Reported by :
Tolerance:
Misc:
Panel variable: PartID
Gage Run Chart of Measure by PartID, OperatorID
STAT > Quality Tools > Gage Study>Gage Run Chart
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MSA Example on Receiving Inspection
Part-to-PartReprodRepeatGage R&R
80
40
0
Per
cent
% Contribution
% Study Var
1098765432110987654321
50
25
0
Parts
Sam
ple
Ran
ge
_R=5.10UCL=16.68
LCL=0
1 2
1098765432110987654321
200
150
100
Parts
Sam
ple
Mea
n
__X=133.1UCL=142.7
LCL=123.5
1 2
10987654321
200
150
100
Parts
21
200
150
100
Operators
10987654321
200
150
100
Parts
Ave
rage
1
2
Operators
Gage name:
Date of study :
Reported by :
Tolerance:
Misc:
Components of Variation
R Chart by Operators
Xbar Chart by Operators
Results by Parts
Results by Operators
Parts * Operators Interaction
Gage R&R (ANOVA) for Results
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Gage Run Chart
38
175
150
125
100
175
150
125
100
1
Operators
Resu
lts
Mean
2 3 4 5
6 7 8 9 10
Mean
1
2
O perators
Gage name:
Date of study :
Reported by :
Tolerance:
Misc:
Panel variable: Parts
Gage Run Chart of Results by Parts, Operators
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Project Tree Electric Motor Reliability
Y Electric motor reliability
y1 Motor reliability
y2 Controller reliability
y3
Mechanical
mounting integrity
y4
Specific
application or use
y11
Stator
y133
Contamination
of the brush
assembly
y134
Spring rate
or condition
issues
y135 Brush
Dimensional
issues
y136
Brush
hardness
issues
y1351 Mean
brush
hardness
y1352 Variation in
brush
hardness
y12
Rotor
y13
Brush y14
Housing
y132
Brush
brittleness
issues
y131 Assembly
stack up
issues
Gage R&R ExplainedProject Tree Diagram