GR&R + Project Tree Diagram.pdf

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Addresses what percent of the Total Variation is taken up by Measurement Error.

Best case/new equipment:

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.

28

GaugeR&R Graphical Output 1

Perc

ent


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:




Measure by PartID




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.

29


Perc

ent


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:




Measure by PartID




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

30


Perc

ent


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:




Measure by PartID




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.

31


Perc

ent


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:




Measure by PartID




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.

32


Perc

ent


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:




Measure by PartID




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?

33


Perc

ent


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:




Measure by PartID




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.

34

GaugeR&R Session Window Output

Perc

ent


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:




Measure by PartID




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.

36

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


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:


R Chart by Operators

Xbar Chart by Operators

Results by Parts

Results by Operators

Parts * Operators Interaction

Gage R&R (ANOVA) for Results

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

GR&R + Project Tree Diagram.pdf

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Transcript of GR&R + Project Tree Diagram.pdf