How to select pieces for GR&R (Gage R&R) Studies?

J

JoelNegrete

#1
Hi everyone, i'm new here
i know that need select 10 pieces for the study, but my question is. can i use diferent size pieces or i need to use the same size??
actually i'm doing GR&R with pieces from .500" to 1.500" and the results was pretty good less than 1% but i think thats isnt correct, also was doing GR&R with the same size pieces( 10 pieces of 1.232") with DEV ± .002"(between operators) and the results where terrible.
Then what is the right way??

i'll thank your help.
 
Elsmar Forum Sponsor

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
#3
Reading Miner's blog will help a lot. But, the key is to compare the measurement of one part number's variation (not a whole family of parts), and that variation needs to be represented as the variation the process will generate over time - not just one lot.

Is 500" to 1.500" the tolerance for a nominal 1.232" characteristic? Or, better yet, does it represent the actual variation of the 1.232" characteristic over time? If so, then you have the right parts. If not, then you have the wrong parts.

If the variation you are presenting to the gage R&R study is for many part numbers - you can recognize that it will not correlate well with the tolerance designed for one part number.
 
M

Mr.Agi

#4
I just participate to a green belt course.
The opinion of the trainer was that the operator who is analyzing the R&R has to maximize the difference btw the parts, so almost 2 pieces over the maximum tolerance and almost 2 under the minimum tolerance. I'm not sure if, in this case, the Stdev calculate is the same of the production process (I mean, my gage is able for the gageR&R experience, but not sure in the production process)
 

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
#5
I just participate to a green belt course.
The opinion of the trainer was that the operator who is analyzing the R&R has to maximize the difference btw the parts, so almost 2 pieces over the maximum tolerance and almost 2 under the minimum tolerance.
If you are going to use this gage for inspection - that is, determining if the part is good or bad - then this sampling methodology may be adequate.

However, if you are using the gage to control the process, then it is incorrect. You must have parts that represent the variation for that process over time.

This distinction is critically important, and if you use the trainers "opinion" for process control, you will get "chunky" data or the variation in the data will be more measurement or gage error than process error, leading you to make incorrect decisions about your process.

The technique suggested by the trainer is also used to fake "good" gage R&R data by artificially increasing the process variation presented to the gage R&R.
 
M

Mr.Agi

#6
I agree with you, in my opinion you have to calculate the correct (or almost correct) st.dev. of the process, so the pieces will be take in sequence during production process
 
Thread starter Similar threads Forum Replies Date
M How to Select FDA Medical Device Product Code? Other US Medical Device Regulations 10
P Material selection - How do we select a raw material? Bolt made of SAE J994 grade 2 Customer and Company Specific Requirements 3
K How do you select the right grips for your tensile tests? Imported Legacy Blogs 0
Y Can manufacturer select AR for MDD different from AR for RED? EU Medical Device Regulations 5
B Historical Standard Deviation or Select Parts for MSA Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
S Excel Help - Equivalent of "Range($G$14:$AD$121).Select" in R1C1 notation Excel .xls Spreadsheet Templates and Tools 5
S A Standard for you to select Standards - ISO 16142-1 Other Medical Device Related Standards 1
R Is it possible to randomly select samples from 1 column to many column Using Minitab Software 2
B How important it is to select Parts that represent the Process Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
B How to select parts for a MSA Study Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 19
C UDI: HIBCC vs. GS1 - Recommendations regarding which one to select Other US Medical Device Regulations 2
T Select Updates for Non-Clinical Engineering Tests - Intravascular Stents Other US Medical Device Regulations 0
C When do I select Team for Black Belt Project? Six Sigma 3
R How to select appropriate standards for Multi-Functional Physical Therapy Equipment IEC 60601 - Medical Electrical Equipment Safety Standards Series 4
L How to select an Authorized Representative CE Marking (Conformité Européene) / CB Scheme 2
somashekar Definition Evaluate and Select ... What are the most common understandings of these words. Definitions, Acronyms, Abbreviations and Interpretations Listed Alphabetically 12
A Who to decide and select Internal Auditors and what are the criteria? Internal Auditing 18
R How to select the the target value from spec. limit (18 samples) Statistical Analysis Tools, Techniques and SPC 4
C How to select the requirements for Continuous Sampling Plan (CSP-1&F), Mil-Std 1235C? Inspection, Prints (Drawings), Testing, Sampling and Related Topics 3
A How to select equipment for MSA (Measurement Systems Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 9
C ASQ Examination Fees Increasing for Select Certifications Professional Certifications and Degrees 1
H How to Select a Statistically Valid Sampling Plan Inspection, Prints (Drawings), Testing, Sampling and Related Topics 10
R Six Sigma vs. TQM - How to Select and What are their Differences? Six Sigma 2
M How to select a consultant to help out for ISO 14001 Certification? Consultants and Consulting 11
kedarg6500 How to Select Checking Aids APQP and PPAP 7
D Variable sample size - Xbar-s charts - How to select A3 and B4 Statistical Analysis Tools, Techniques and SPC 11
C What is the Best Way to Select a Registrar? The Reading Room 3
S Attribute MSA - Risk analysis -- How to select the samples Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
Q Gage R&R - How to select samples near the limits? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
S How to select the part for Gage R&R Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
Casana How to select a consultant? What criteria to consider and look for when looking Consultants and Consulting 5
P How To Select Regulatory (Regulatory Requirements?) For Implement Iso/ts 16949 IATF 16949 - Automotive Quality Systems Standard 3
Y How to select the most suitable person to be the Management Representative? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 17
B Operating Range & Measurement System Discrimination:How to select parts for R&R test? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
R Which pieces of equipment require equipment validation? ISO 13485:2016 - Medical Device Quality Management Systems 1
ScottK Statistical basis for 30 pieces for FAI 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 7
M How many Pieces to Test - Sterility Testing USP EU Medical Device Regulations 2
M Cpk - How to calculate when the number of samples is less than 30 pieces? Capability, Accuracy and Stability - Processes, Machines, etc. 7
C AS9102 - How many pieces need to go on the First Article paperwork? AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 6
D Force Testing Round Pieces that are Twisted Together Manufacturing and Related Processes 9
V JCI standard numbers of pieces required for Capability Study? APQP and PPAP 2
L Sigma & the Distributor - Rejected pieces from prior shipments to current measures Six Sigma 7
C Equivalence Studies - Validation Activities for several Identical Pieces of Equipment Manufacturing and Related Processes 1
C Equivalence Studies - Validation Activities for several Identical Pieces of Equipment Qualification and Validation (including 21 CFR Part 11) 2
T why CPK <1.0 regarding two pieces of control charts of torque wrench? Statistical Analysis Tools, Techniques and SPC 2
M Putting First Pieces with Masters - Need opinions Inspection, Prints (Drawings), Testing, Sampling and Related Topics 3
P Data Collection Tools - PC Board Assembly (5-20 pieces in a run) Quality Tools, Improvement and Analysis 0
G Scope Of ISO 17025 Certification - 3000 to 5000 pieces of equipment in the field ISO 17025 related Discussions 5
L Sample pieces for customer - still document the same? Document Control Systems, Procedures, Forms and Templates 2
M Sampling Method for 25 pieces a week of a cable with connectors Inspection, Prints (Drawings), Testing, Sampling and Related Topics 2

Similar threads

Top Bottom