Visual Inspection (Attribute Data) Gage R&R

B

bobby j

#1
Hi,

So I just wanted to know if there was a way to do a Gage R&R on a visual inspection. There is no physical gage and I have 3 operators doing visual inspections on parts and I would like to know if there was a way to do a Gage R&R study. If so, how? I have Minitab and I am looking on the attibute gage study, is this it? How do I use it?

Thanks a lot.
 
Last edited by a moderator:
Elsmar Forum Sponsor
U

Umang Vidyarthi

#2
Re: Visual Inspection Gage R&R

Hi,

So I just wanted to know if there was a way to do a Gage R&R on a visual inspection. There is no physical gage and I have 3 operators doing visual inspections on parts and I would like to know if there was a way to do a Gage R&R study. If so, how? I have Minitab and I am looking on the attibute gage study, is this it? How do I use it?

Thanks a lot.
Hello Bobby, :bigwave: Welcome to the cove :bigwave:

Very good first post. Let us say there are three operators A, B & C. The instruments are the eyes of the operators say E1, E2 & E3. Now operator A can only use E1, and so on. You can neither have one operator using the three instruments, nor have a common instrument for the three operators. Since appraisers and instruments are not interchangeable, hence it will be a fruitless exercise.

Umang :D
 
Last edited by a moderator:

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
#3
Re: Visual Inspection Gage R&R

Let us say there are three operators A, B & C. The instruments are the eyes of the operators say E1, E2 & E3. Now operator A can only use E1, and so on. You can neither have one operator using the three instruments, nor have a common instrument for the three operators. Since appraisers and instruments are not interchangeable, hence it will be a fruitless exercise.
I consider the visual standard the gage, not they eyes - the eyes are a function the operator error. The key of that study is will the operators correctly identify known good and known bad parts. You need to understand if they are capable of agreeing with the standards. If not, the standard needs to be clearer or another approach must be used.

Be sure to randomize the specimens - maybe even have them presented by another person to the operator to avoid bias (memorizing).
 

Bev D

Heretical Statistician
Staff member
Super Moderator
#4
Re: Visual Inspection Gage R&R

Of course you can!
I do it all of the time and I've found it to be quite valuable.
Google the article "When Quality is a matter of taste" by yDavid Futrell

Then use the search engine here to search for attribute gage (<-- key words) R&R studies...

tomorrow, I'll try to remember to post the formulas - try searching for "verification and validation of measurement systems" I posted this document in a thread and it includes a description of this process...
 
T

TWIBlogger

#7
Re: Visual Inspection Gage R&R

I just completed a Gage R&R study this morning.

Just looking for any opinions on holes that I may have in my approach...please be gentle!

33 samples known to pass or fail. A plurality of visual attributes are inspected per piece. So, the first variable that may be a problem for this study is that inspectors may fail the same part for different reasons. Something to chew on...

Anyway, average reproducibility is .79.

Average repeatability is .73

I determined Cohen's Kappa, just for fun, per inspector. The average k=.37, ranging from .25 to .58

My understanding is that I want R&R to be +.90. Is this correct or a good goal? Is it even feasible? What is the next best step to close the gap between .7X and .90? I'm thinking a meeting where the inspectors sit down and calibration over the differences in pass/fail?

Is kappa meaningful at all in this sort of situation?

Back to the plurality of attributes per piece. Should I conduct gage R&R per attribute? Would this help me better understand our weaknesses? Sort of a pareto approach to try and pinpoint precisely what is lower our R&R? Thoughts??

Thanks in advance.
Bryan
 
T

TWIBlogger

#8
Re: Visual Inspection Gage R&R

Sorry, I forgot to add that I had eight inspectors, two trials each.
 

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
#9
Re: Visual Inspection Gage R&R

My understanding is that I want R&R to be +.90. Is this correct or a good goal? Is it even feasible? What is the next best step to close the gap between .7X and .90?
Rules of Thumb
Parameter Acceptable Marginal Unacceptable
E >= .90 .80 - .90 < .8

P(FR) <= .05 .05 - .10 > .10

P(FA) <= .02 .02 - .05 > .05

B .80 - 1.20 .50 - .80 or 1.20 - 1.50 < .50 or > 1.50

Are they feasible? It depends - particularly on how obvious the fail condition is to the pass condition. For surface conditions (as an example) the level of permissible scratches (how many, how deep, how long, etc.) may not achieve .90. Detecting missing components can be 1.00.

Back to the plurality of attributes per piece. Should I conduct gage R&R per attribute? Would this help me better understand our weaknesses? Sort of a pareto approach to try and pinpoint precisely what is lower our R&R? Thoughts??
You could set up the gage R&R specimens with some failing parts with single failing attributes, and others with combinations. You are not limited to the number of specimens you present to the operators. This may help sort out if there are any specific attributes or combination of attributes that create discrimination error - especially if they can exist singly in the process output. You could also do gage R&R per attribute...little more work, but may provide further insight.

I'm thinking a meeting where the inspectors sit down and calibration over the differences in pass/fail?
That may be one of the last things you do, as one you have those conversations the probability of bias will increase since the operators will know that is what you are looking at.
 
T

TWIBlogger

#10
Re: Visual Inspection Gage R&R

Rules of Thumb
Parameter Acceptable Marginal Unacceptable
E >= .90 .80 - .90 < .8

P(FR) <= .05 .05 - .10 > .10

P(FA) <= .02 .02 - .05 > .05

B .80 - 1.20 .50 - .80 or 1.20 - 1.50 < .50 or > 1.50
Thank you for the detailed feedback...however, can you tell me what each parameter represents? :eek:

Are your parameters the same thing as mine? If so, can you match them up to clarify?:eek:
 
Thread starter Similar threads Forum Replies Date
R Can a Attribute Study be considered a Visual Inspection? Reliability Analysis - Predictions, Testing and Standards 6
Sean Kelley Visual Inspection Galvanized Attribute Study Quality Tools, Improvement and Analysis 2
J MSA for Attribute Visual Inspection Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
J The appropriate Attribute MSA for Automatic Visual Inspection Machine Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
S Attribute MSA Visual Inspection Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
B Attribute MSA for Visual Inspection via Camera Automatic Inspection Tool Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
Barahir Visual Inspection - Capability Study on Attribute Data Capability, Accuracy and Stability - Processes, Machines, etc. 13
A MSA - Is an attribute study required for visual inspection? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
Marc Visual Inspection - Color Vision Coffee Break and Water Cooler Discussions 15
S Need Assistance in Visual Inspection - Tiny electronic components AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 11
John Predmore What size pinhole can be reliably detected using visual inspection? Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
P Gage R&R on Visual Inspection Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 15
B Gage R & R on Visual Inspection using the Cross Tabulation Method IATF 16949 - Automotive Quality Systems Standard 4
L IATF 16949 7.1.5.1.1 Measurement System Analysis (MSA) - Visual Inspection IATF 16949 - Automotive Quality Systems Standard 14
S Do you use audio-visual streaming during FDA inspection? US Food and Drug Administration (FDA) 3
D Visual Inspection with No Visual Reference General Measurement Device and Calibration Topics 2
N How to reduce RPN of Visual Inspection Process FMEA and Control Plans 6
alonFAI Finished PCB Final Visual Inspection Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
N Visual Inspection, Terminology for Process (Tin Soldiering?) Inspection, Prints (Drawings), Testing, Sampling and Related Topics 2
G Visual Inspection of Machined Parts - Best Methods Inspection, Prints (Drawings), Testing, Sampling and Related Topics 8
A Cosmetic Visual Inspection Specification Advantages Manufacturing and Related Processes 7
A Cosmetic Spec - Convincing Management Visual Inspection Standard is Necessary Manufacturing and Related Processes 5
Sean Kelley FMEA Visual Inspection Detection Rating FMEA and Control Plans 5
G Thoughts on Audit Finding for not doing Gage R and R for Visual Inspection Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
J Visual Inspection of Roughness General Measurement Device and Calibration Topics 5
Sean Kelley Gage R&R for Visual Inspection for Sheet Steel Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
T Repeated Inspection - Probability of Visual Inspection catching Defects Inspection, Prints (Drawings), Testing, Sampling and Related Topics 2
5 Visual Weld Inspection Report - Example needed Manufacturing and Related Processes 3
G Sample Size for 2900 ppm Visual Defects Inspection Requirement Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
P Visual Inspection Device for Tiny Rubber Parts General Measurement Device and Calibration Topics 10
B Control Plan Entries - Outgoing Visual Inspection - What should be on a Control Plan? FMEA and Control Plans 18
S High Speed Visual Inspection System vs. Coordinate Machining System Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
I Defectives (ppm) coming from Visual Inspection Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1
B Effectiveness of 200% Visual Inspection to Identify Defects and Defectives Inspection, Prints (Drawings), Testing, Sampling and Related Topics 32
S Visual inspection standards - VDA 16 or Equivalent Inspection, Prints (Drawings), Testing, Sampling and Related Topics 6
T Inspection Method and Control Method for Visual Inspection? Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
automoto Visual Inspection of a Weld - MSA (Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
N Tyvek Pouch Seal - Visual Inspection 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 19
Chennaiite High Technology Visual Inspection for Casting and Forging Parts - Zero Defects Inspection, Prints (Drawings), Testing, Sampling and Related Topics 11
A Injection Mold 100% Visual Inspection - Short Shots and Debris not being found Inspection, Prints (Drawings), Testing, Sampling and Related Topics 22
A Ford's requirements for Lumens/Lighting for Visual Inspection Customer and Company Specific Requirements 11
F MSA and Control Plan - Satisfying Visual Inspection Requirements IATF 16949 - Automotive Quality Systems Standard 5
D Visual Inspection - How do you quantify Visual Inspection for TS16949 Inspection, Prints (Drawings), Testing, Sampling and Related Topics 2
S Applying ANSI/ASQ Z1.4 given known lot size and 100% visual inspection AQL - Acceptable Quality Level 2
R Visual Inspection Calibration Inspection, Prints (Drawings), Testing, Sampling and Related Topics 3
A Visual Inspection Frequency and is there any standard that for visual attributes? AQL - Acceptable Quality Level 2
K Visual inspection and acceptance criteria Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1
R Visual Weld inspection training Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1
quality1 PCBA Visual Inspection Tools & Methods - discounting Optical Tools Manufacturing and Related Processes 11
V Detection rating for visual inspection in PFMEA FMEA and Control Plans 19

Similar threads

Top Bottom