Gage R&R for an Xray instrument for measuring plating thickness

D

Dwight357

#1
I was asked to perform a gage R&R study for an Xray instrument measuring plating thickness. The total %RR was very high in spite of any intervention. I think this is due to the variation I get in the second decimal place (100ths of microns) which can't really be controlled. How do I get a valid gage RR? The spec limitations are given only in whole microns. Can I, for instance, just drop the decimal portions and do the gage study?:frust:
 
Elsmar Forum Sponsor
S

sauhiew

#2
Re: Gage R&R for xray

Would you care to show a few actual readings and specs?

Often times, I have encountered some mis-interpretation data. For example, a hole dimension has a tolerance of +.003"/-0. If the measuring gage is only precise to .001", then any movement will eat up 33% of the tolerance, resulting in poor GR&R. The problem could be resolved to get a more precise gage to .0002".
 

Jim Wynne

Staff member
Admin
#3
Re: Gage R&R for xray

I was asked to perform a gage R&R study for an Xray instrument measuring plating thickness. The total %RR was very high in spite of any intervention. I think this is due to the variation I get in the second decimal place (100ths of microns) which can't really be controlled. How do I get a valid gage RR? The spec limitations are given only in whole microns. Can I, for instance, just drop the decimal portions and do the gage study?:frust:
Some additional information about the test protocol (how the test was conducted--number of operators, parts used, who sets up the samples, e.g.) would be helpful, and it would also be good to know:
  • Have you verified repeatibility of the device itself, reading a calibrated master standard (For example, reading the standard 10 times in succession without moving it)?
  • Has the device been properly calibrated?
 
D

Dwight357

#4
Re: Gage R&R for xray

Thanks for the reply.we used 3 operators and ten samples. We did try taking repeated measures of the same sample at a few seconds interval each. There was a good bit of variation in the last (2nd) decimal place. Just before that we set up a newer monitor that we thought might reduce variation because it seemed easier to focus. This brought the %RR down from 80% to about 51%...still quite high.
 

Jim Wynne

Staff member
Admin
#5
Re: Gage R&R for xray

Thanks for the reply.we used 3 operators and ten samples. We did try taking repeated measures of the same sample at a few seconds interval each. There was a good bit of variation in the last (2nd) decimal place. Just before that we set up a newer monitor that we thought might reduce variation because it seemed easier to focus. This brought the %RR down from 80% to about 51%...still quite high.
More questions: When you say "repeated measures of the same sample," what do you mean by "sample"? What coating and substrate? What's the collimator size? How was the collimator targeted in the R&R study? I'm assuming that since you say a new monitor affected the results, that most of the variation is in the device, and not between operators?
 

Bev D

Heretical Statistician
Staff member
Super Moderator
#6
Re: Gage R&R for xray

also if you post your actaul data we can help you better without guessing...
 
#7
I have done many gage R & R studies for plating. The key to having accurate results is to make sure that array of samples that you use covers the full specification,ie, if the specification is 8-12 microns then your samples should cover that range. If your samples are close together in thickness, then the results will be skewed as to showing that you have operator problems.
 

Miner

Forum Moderator
Staff member
Admin
#8
I have done many gage R & R studies for plating. The key to having accurate results is to make sure that array of samples that you use covers the full specification,ie, if the specification is 8-12 microns then your samples should cover that range. If your samples are close together in thickness, then the results will be skewed as to showing that you have operator problems.
That all depends on which metric the OP is using and for what reason. Your suggestion is acceptable IF and ONLY IF the OP is only concerned about Inspection to Tolerance and uses P/T Ratio.

If the OP uses the device for SPC and uses %GRR as the metric, your suggestion is incorrect. The samples must reflect the actual process variation.

Since many posters use %GRR in a generic manner, not realizing the distiction between the two metrics, we cannot infer the OP's actual intent.
 
Thread starter Similar threads Forum Replies Date
T Plug Gage Calibration Calibration and Metrology Software and Hardware 1
L Gage R&R TMV Acceptance Criteria Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
S MSA for attribute relation gage Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
E Zero part to part variation - Gage R&R project Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 15
M Gage R&R and right way to measure Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 16
L Gage RandR on automated equipment. IATF 16949 - Automotive Quality Systems Standard 7
B Gage calibration frequency, ISO and IATF - What are the requirements Calibration Frequency (Interval) 3
D Difference between Test Method Validation and Gage R&R Qualification and Validation (including 21 CFR Part 11) 18
R Determining Uncertainty from Gage R&R Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
C Correct Calibration Method for Dial Depth Gage General Measurement Device and Calibration Topics 6
C Gage Block Wringing General Measurement Device and Calibration Topics 3
B Gage R&R with NDC=1 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 19
S Type 1 Gage R&R or something else? Reliability Analysis - Predictions, Testing and Standards 6
G Should I perform Gage R&R only at the beginning of a new project? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
V Thread Plug Gage Pitch GO Diameter out of spec AQL - Acceptable Quality Level 8
G Gage R&R - Where am I going wrong? Part of a FAIR submission (Aerospace) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
R Gage R&R Excel templates Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
K Gage R&R with more than 3 appraisers Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
Anerol C Gage R&R Template AIAG 4th Edition IATF 16949 - Automotive Quality Systems Standard 3
T Attributes SPC study - Attributive control (Go gage) Statistical Analysis Tools, Techniques and SPC 5
S Capability or Gage R&R Study for Leak Tester? Reliability Analysis - Predictions, Testing and Standards 15
N % Tolerance - Type 1 study on the gages, then a gage R&R (ANOVA) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
M Definitive answer on Type 1 vs Type 2 vs Type 3 Gage Study Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
V Gage Management and Gage R&R Software General Measurement Device and Calibration Topics 1
D Gage R&R Study on Load Cells - Large chemical blending tanks IATF 16949 - Automotive Quality Systems Standard 1
B Minitab Type 1 Gage Study on True Position Question Measurement Uncertainty (MU) 1
S Gage R&R on alloy Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
8 Need Help - Runout - Function Gage Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
L Gage R&R studies for identical Devices - Need to confirm the requirement to perform them Reliability Analysis - Predictions, Testing and Standards 2
G Stab Pin Size For Check Gage Inspection, Prints (Drawings), Testing, Sampling and Related Topics 3
E Functional Gage for TOP applied at RFS Design and Development of Products and Processes 5
F No reproducibility Error in Gage R&R? Reliability Analysis - Predictions, Testing and Standards 4
M Template for Attribute Gage R & R wanted Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
G Warning about Deltronic Gage Pins - The "Certification of Accuracy" document General Measurement Device and Calibration Topics 13
A Gage type 1 study on CMM Capability, Accuracy and Stability - Processes, Machines, etc. 2
Q Gage R&R for Instant Measurement Machine Manufacturing and Related Processes 6
M Gage R&R with large inter part variance - Torque Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
D Do we need normal data for gage r&r studies? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
D Do I need part variation while doing Destructive Variable Gage R&R MSA study Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 19
S Gage R&R Standard Deviations Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
J Informational Gage R&R: Swapping operators Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
S Gage R & R for large amount of inspections IATF 16949 - Automotive Quality Systems Standard 10
S Ring Gage Thermal Expansion General Measurement Device and Calibration Topics 4
L Gage R&R for test precision or uncertainty prediction? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
S Minor diameter of threaded ring gage General Measurement Device and Calibration Topics 1
A Does Torque Gage Need Validation? Reliability Analysis - Predictions, Testing and Standards 4
J Ignoring a Failed Gage R&R and upcoming external audit IATF 16949 - Automotive Quality Systems Standard 22
R Scaling a Gage R&R - 2 holding fixtures each with 10 nests Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
B Gage R&R Acceptable (10-30%), deduct Total Variation from Tolerance Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 12
apestate Inexpensive Gage Blocks for small aerospace startup shop General Measurement Device and Calibration Topics 1

Similar threads

Top Bottom