What is Gauge Capability? Dial Thickness Gage and Digital Vernier Calipers

I

igsram233

#1
Recently we had an process audit audit by our potential customer.

While at the Quality Stage he wanted to show him how we measure the dimensions of the component. We showed him that we use Dial Thickness Gauges and Digital Vernier Calipers. He then asked us about something called Gauge Capability :)confused: )and whether we had done that on the instruments. we did not know that.

We know a little bit about Process Capability (Cp & CpK).

I would like some one to help me in that.

Thanx in advance.
 
Elsmar Forum Sponsor

Miner

Forum Moderator
Staff member
Admin
#2
Re: What is Gauge Capability? Dial Thickness Gauges and Digital Vernier Calipers

Your customer is probably referring to MSA, Measurement System Analysis. The evaluation of the Xbar chart (part of the MSA) for >50% of the points out of control is sometimes refferred to as Measurement Capability, but your customer is probably refferring to the total MSA.

Try searching within this forum for additional information. I also recommend obtaining the MSA manual from AIAG (Automotive Industry Action Group) at www.aiag.org.
 

Hershal

Metrologist-Auditor
Staff member
Super Moderator
#4
Re: What is Gauge Capability? Dial Thickness Gauges and Digital Vernier Calipers

I recommend you have the instruments calibrated by your local NABL-accredited calibration lab, and make sure you get the uncertainty reported.....then you will know just about everything about the instrument and its reported measurements.....then all you need is you appliction of the measurements.

Hershal
 
R

ralphsulser

#5
Re: What is Gauge Capability? Dial Thickness Gauges and Digital Vernier Calipers


Atul,
You have been very helpful about this subject. However, I must admit that GR&R has not been my forte. My question is what are the targets we should be looking for in the results of a GR&R using the ANOVA method? Such as what are good numerical scores for the different reported values? How do we determine what is acceptable and what is not, and by how much?
Someone else has been doing all these, but as previously mentioned we now have to report results a ANOVA. Appreciate your continued assistance.
 
R

ralphsulser

#6
Re: What is Gauge Capability? Dial Thickness Gauges and Digital Vernier Calipers

ralphsulser said:
Atul,
You have been very helpful about this subject. However, I must admit that GR&R has not been my forte. My question is what are the targets we should be looking for in the results of a GR&R using the ANOVA method? Such as what are good numerical scores for the different reported values? How do we determine what is acceptable and what is not, and by how much?
Someone else has been doing all these, but as previously mentioned we now have to report results a ANOVA. Appreciate your continued assistance.
Anyone else care to chime in on this one? We have Ford coming in to scrutinize our results.
 

Miner

Forum Moderator
Staff member
Admin
#7
Re: What is Gauge Capability? Dial Thickness Gauges and Digital Vernier Calipers

I may not understand the question completely, but if I do, the targets are the same for the ANOVA method as they are for the Range method.

That is, </= 10% is ideal, between 10% and 30% is acceptable depending on the criticality of the application and the economics of improving, and > 30% is not acceptable.

The results for each method should be very similar. The Range method is easier to use when performing calculations by hand, while the ANOVA method is more accurate and can separate the Operator x Part interaction. The procedure for collecting the data is the same, so if you have a computer and the software available, there is no reason not to use the ANOVA method.

The interpretation of the results is basically the same for each method.
 
R

ralphsulser

#8
Re: What is Gauge Capability? Dial Thickness Gauges and Digital Vernier Calipers

Miner said:
I may not understand the question completely, but if I do, the targets are the same for the ANOVA method as they are for the Range method.

That is, </= 10% is ideal, between 10% and 30% is acceptable depending on the criticality of the application and the economics of improving, and > 30% is not acceptable.

The results for each method should be very similar. The Range method is easier to use when performing calculations by hand, while the ANOVA method is more accurate and can separate the Operator x Part interaction. The procedure for collecting the data is the same, so if you have a computer and the software available, there is no reason not to use the ANOVA method.

The interpretation of the results is basically the same for each method.
Thanks Miner, can you tell me what do the rest of these numbers tell me:
How do I interpret as OK, or NG and how much. 3 appraisers, 3 trials, 10 parts.
Two-Way ANOVA Table With Interaction

Source DF SS MS F P
Part 9 0.0000152 0.0000017 2.2443 0.069
Operator 2 0.0000422 0.0000211 28.0328 0.000
Part * Operator 18 0.0000136 0.0000008 0.9823 0.491
Repeatability 60 0.0000460 0.0000008
Total 89 0.0001170


Alpha to remove interaction term = 0.25


Two-Way ANOVA Table Without Interaction

Source DF SS MS F P
Part 9 0.0000152 0.0000017 2.2136 0.030
Operator 2 0.0000422 0.0000211 27.6493 0.000
Repeatability 78 0.0000596 0.0000008
Total 89 0.0001170


Gage R&R

%Contribution
Source VarComp (of VarComp)
Total Gage R&R 0.0000014 93.34
Repeatability 0.0000008 49.43
Reproducibility 0.0000007 43.91
Operator 0.0000007 43.91
Part-To-Part 0.0000001 6.66
Total Variation 0.0000015 100.00


Study Var %Study Var
Source StdDev (SD) (6 * SD) (%SV)
Total Gage R&R 0.0012007 0.0072045 96.61
Repeatability 0.0008738 0.0052428 70.30
Reproducibility 0.0008236 0.0049414 66.26
Operator 0.0008236 0.0049414 66.26
Part-To-Part 0.0003209 0.0019252 25.82
Total Variation 0.0012429 0.0074573 100.00


Number of Distinct Categories = 1
Gage R&R for Response

Appraiser 1 Trial 1 0.652 0.65 0.65 0.65 0.651 0.65 0.651 0.65 0.651 0.65
> Trial2 0.65 0.65 0.65 0.65 0.651 0.65 0.65 0.651 0.65 0.65
Olden Trial3 0.65 0.651 0.65 0.651 0.65 0.652 0.65 0.651 0.651 0.65
Trial4
Trial 5
Total 1.952 1.951 1.95 1.951 1.952 1.952 1.951 1.952 1.952 1.95
Average-Appraiser 1 0.65067 0.6503 0.65 0.6503 0.6507 0.6507 0.6503 0.6507 0.6507 0.65
Range1 0.002 0.001 0 0.001 0.001 0.002 0.001 0.001 0.001 0
Appraiser 2 Trial 1 0.653 0.651 0.65 0.649 0.652 0.651 0.65 0.652 0.65 0.651
here-> Trial2 0.65 0.651 0.652 0.651 0.65 0.651 0.652 0.652 0.65 0.651
Jamace Trial3 0.651 0.651 0.65 0.651 0.65 0.651 0.65 0.654 0.653 0.653
Trial4
Trial 5
Total 1.954 1.953 1.952 1.951 1.952 1.953 1.952 1.958 1.953 1.955
Average-Appraiser 2 0.65133 0.651 0.6507 0.6503 0.6507 0.651 0.6507 0.6527 0.651 0.6517
Range2 0.003 0 0.002 0.002 0.002 0 0.002 0.002 0.003 0.002
Appraiser 3 Trial 1 0.653 0.652 0.652 0.651 0.653 0.653 0.652 0.653 0.652 0.652
Trial2 0.65 0.652 0.652 0.651 0.653 0.653 0.652 0.653 0.652 0.651
Wanda Trial3 0.652 0.653 0.652 0.65 0.654 0.651 0.652 0.653 0.652 0.652
Trial4
Trial 5
 

Miner

Forum Moderator
Staff member
Admin
#9
Re: What is Gauge Capability? Dial Thickness Gauges and Digital Vernier Calipers

ralphsulser said:
Thanks Miner, can you tell me what do the rest of these numbers tell me:
How do I interpret as OK, or NG and how much. 3 appraisers, 3 trials, 10 parts.
Two-Way ANOVA Table With Interaction

Source DF SS MS F P
Part 9 0.0000152 0.0000017 2.2443 0.069
Operator 2 0.0000422 0.0000211 28.0328 0.000
Part * Operator 18 0.0000136 0.0000008 0.9823 0.491
Repeatability 60 0.0000460 0.0000008
Total 89 0.0001170


Alpha to remove interaction term = 0.25
The only numbers of interest to you are the number under the column P. This is the p-value for that factor.
A p-value less than 0.05 is considered statistically significant.

The other numbers are intermediate calculations to obtain p.
DF is Degrees of Freedom which is essentially the number of levels - 1.
SS is the Sum of Squares or the variance of the term.
MS is the Mean Square or the SS/DF.
F is the F-ratio or the MS/MS(repeatabilty).
P is determined from an F - table using the degrees of freedom in the numerator and denominator.

Your software is using an Alpha of 0.25 to test the significance of the Part x Operator interaction.
If the P value for this interaction is > 0.25 it pools the SS into the SS Repeatability and recalculates the ANOVA.

This is the ANOVA displayed below.

ralphsulser said:
Two-Way ANOVA Table Without Interaction

Source DF SS MS F P
Part 9 0.0000152 0.0000017 2.2136 0.030
Operator 2 0.0000422 0.0000211 27.6493 0.000
Repeatability 78 0.0000596 0.0000008
Total 89 0.0001170
The following are the sections that you will be most interested in evaluating.
ralphsulser said:
Gage R&R

%Contribution
Source VarComp (of VarComp)
Total Gage R&R 0.0000014 93.34
Repeatability 0.0000008 49.43
Reproducibility 0.0000007 43.91
Operator 0.0000007 43.91
Part-To-Part 0.0000001 6.66
Total Variation 0.0000015 100.00
This section simply shows the sources of variation in the study. It is used like a Pareto to focus improvement efforts.

raplhulser said:
Study Var %Study Var
Source StdDev (SD) (6 * SD) (%SV)
Total Gage R&R 0.0012007 0.0072045 96.61
Repeatability 0.0008738 0.0052428 70.30
Reproducibility 0.0008236 0.0049414 66.26
Operator 0.0008236 0.0049414 66.26
Part-To-Part 0.0003209 0.0019252 25.82
Total Variation 0.0012429 0.0074573 100.00


Number of Distinct Categories = 1
The %Study Variation for Total Gage R&R is the same as the %GRR. This is the number that you compare to the <10%, 10 - 30% and >30% criteria.
The Number of Distinct Categories is the same as ndc. This number should be a minimum of 5.

This study shows the gage to be unacceptable for use in process control or process improvement. Does the variation of part represent the variation of the process? If the parts are representative of the process variation, you have a problem with both repeatability and reproducibility, but not with an operator x part interaction.

The graphs may indicate the reasons for this, but I don't have access at home. I'll try tomorrow.
 
R

ralphsulser

#10
Re: What is Gauge Capability? Dial Thickness Gauges and Digital Vernier Calipers

Hey Miner,
Thanks a bunch for taking the time to provide some evaluations of the data.
Appreciate your input and help.:thanks:
 
Thread starter Similar threads Forum Replies Date
M Capability of a Vibration Measurement Gauge Quality Tools, Improvement and Analysis 3
A Score capability of measurement of gauge Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
M Gauge R&R Capability in the Plastics Industry Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
M Calculating Capability-Subtract Gauge R & R Error? Statistical Analysis Tools, Techniques and SPC 1
C Gauge R&R Question Using Minitab Software 1
S Calibration Frequency for Slip Gauge Kit used for CMM Calibration? General Measurement Device and Calibration Topics 0
J Gauge Suggestion: Specialty or Custom General Measurement Device and Calibration Topics 1
F Calibrating Taper Sleev/Plug Gauge General Measurement Device and Calibration Topics 0
I How many gauges in a Go/No Go Gauge? General Measurement Device and Calibration Topics 7
J Standard used to determine if check fixture gauge is acceptable Reliability Analysis - Predictions, Testing and Standards 2
J Designing new gauge tracking software IATF 16949 - Automotive Quality Systems Standard 4
R Gauge R&R on pre-set torque wrench Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
C Aluminum galling on thread plug gauge Manufacturing and Related Processes 10
J Gauge R&R on a torque measurement Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 11
K I’m looking for a square probe for my linear height gauge Manufacturing and Related Processes 1
A Gauge Study for Small Lots Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
G Supplier Checking With Gauge Pin Problem Solving, Root Cause Fault and Failure Analysis 2
H Analog Pressure Gauge with no EN837 accuracy class information General Measurement Device and Calibration Topics 5
G Gauge R&R on multiple dimensions using 3D measurement system Capability, Accuracy and Stability - Processes, Machines, etc. 6
H Thread Plug Gauge Tolerances General Measurement Device and Calibration Topics 3
R Do Brands Matter When Purchasing Bore Gauge? General Measurement Device and Calibration Topics 2
D Using "Particle Size Standard" templates as gauges - How to avoid giving a gauge # while using for process control? General Measurement Device and Calibration Topics 2
D AS9100 Inspection records - Is there a requirement to have gauge ID and calibration status AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 5
G Comparing Gauge Blocks - Translating the calibration between the master set and the QA set General Measurement Device and Calibration Topics 2
F Gauge R&R & Calibration Intervals Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 14
Ron Rompen Source needed for Spline Form gauge (GO and NOGO members) General Measurement Device and Calibration Topics 3
S How to calculate the maximum allowable hysteresis of a pressure gauge General Measurement Device and Calibration Topics 1
S Gauge R and R - Product - Conveyor belt with threads that goes on Sprocket Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
R Feeler Gauge Calibration - What tolerance is used for calibrating feeler gauges? General Measurement Device and Calibration Topics 4
F Holes position inspection - Calculation of centre distance and plug sizes of a gauge Inspection, Prints (Drawings), Testing, Sampling and Related Topics 5
K Measurement Uncertainty Budget (MU) of for Ultrasonic Thickness gauge Measurement Uncertainty (MU) 1
R Radius Gauge R&R Study Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
A Calibration of Pressure Gauge, How to Determine Calibration Tolerance General Measurement Device and Calibration Topics 1
S Thread Ring Gauge verification General Measurement Device and Calibration Topics 6
G Uncertainty Budget Examples for Caliper, Micrometer and Dial Gauge Measurement Uncertainty (MU) 3
S Pressure Gauge Calibration Uncertainty Calibration and Metrology Software and Hardware 5
N Correct reading for analog pressure gauge ISO 17025 related Discussions 2
Ron Rompen Gauge Design Standards Inspection, Prints (Drawings), Testing, Sampling and Related Topics 2
B Gauge CAD certification to Part CAD vs. Gauge certification to Part CAD General Measurement Device and Calibration Topics 1
shimonv Feeler Gauge as a Medical Device Accessory EU Medical Device Regulations 3
C Proper Thickness Gauge for Foam/Felt and Soft Materials General Measurement Device and Calibration Topics 5
J What kind of Tool and Gauge in IATF 16949 Clause 8.5.1.6? IATF 16949 - Automotive Quality Systems Standard 1
alonFAI Gauge R&R for a Peel Tester (tensile tester) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 11
R Height gauge to measure short hard to access heights General Measurement Device and Calibration Topics 3
V Why Gauge R&R 10% is acceptable for variable instruments ? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
B Can we calibrate a standard pin with a gauge? General Measurement Device and Calibration Topics 2
C How to perform Gauge R & R on Automated Test & Measurement Equipment Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
I How to determine the thread wire size needed - Buttress Thread Gauge General Measurement Device and Calibration Topics 3
V Inactive Gauge Retention Time - PPAP Section 6 Requirements APQP and PPAP 1
Q Pin Gauge Setup - Measuring the OD of a Catheter Manufacturing and Related Processes 1

Similar threads

Top Bottom