# MSA Manual 3rd Edition - R&R, Linearity, Bias, Stability - Small Company Many Gages

M

#### Martin Rudkin

MSA and the 3rd Edition

We are a injection moulding and metal pressing company supplying 1st tier automotive suppliers - hence being pushed down QS9k.

I am at present trying to compile an MSA procedure/process. We have many parts which are 'live' within our company and to carry our MSA on all of them would not be feasible. (time/man power)

I would like to carry out Equipment Studies(micrometers, callipers, etc) but I am unsure how to include everything our auditor has been looking for - R&R, Linearity, Bias, Stability in a manner which is efficient and complies to QS9k 3rd Ed.

I have been slogging through the MSA booklet but it does not make it any clearer.

------------------

T

#### TheOtherMe

The MSA manual is primarily aimed at repetitive measurements of a specific dimension on a specific part. Take a look at page 37. Linearity = |Slope| x Process Variation. Take your equipment and do a few studies on a few different parts. Companre the part to part results. Now you have qualification of the instrument for measuring other parts by 'similarity'. Remember you are looking at a part to part situation and so you might want to do an R&R on one part as you need a way to address process variation. Some issues should be understood as well such as the differences you will find using the same instrument (such as micrometers or calipers) on different materials (you say you injection mold and you press metal).

What do you mean by " 'live' within our company"?

M

#### Martin Rudkin

Thanks for your reply, it has provided me with ideas.

What I meant by live is that they are in current production.

The problem is that if I was to carry out an MSA study on each 'live' part, I would have to carry out more than 1000 MSA studies - not exactly my idea of fun!

Also, if possible could you explain in layman terms 'Process Variation' So far, within the MSA manual, I can only find it given as a figure but not how to calculate that figure.

R

#### Roger Eastin

Basically, the process variation is the spread of the process or, a more inexact term might be RANGE of values (for a given parameter) you expect to see from your process. For a normally-distributed process, the process variation is described by the standard deviation (sigma). This metric allows you to describe your range of values in terms of, for instance, % of values within your tolerance. If you use a control chart method to do your MSA, then calculate sigma using the R-bar/d2 method(a list of d2 values is given in chapter 2, table 2). If you are not using this method, the easiest way to calculate sigma is the button on your scientific calculator (no joke!). Otherwise, you can use a hand calculation which is located in statistics text books. This should be a last resort unless you are a purist! If your process is not normally distributed, you can use other metrics. Hopefully this description is in layman's terms!

[This message has been edited by Roger Eastin (edited 03 September 1999).]

M

#### Martin Rudkin

Thanks Roger, sorry to be a pain but going back to TheOtherMe's reply about page 37 of the MSA handbook, the process variability has been calculated as 6.0 from the measurements taken.

Do you know how they have arrived at 6.0? Is it a sum the variances from each reference size/part trial?

#### Marc

##### Hunkered Down for the Duration
Staff member
I can't say where they derived 6 as the process variation for the example. This is not my forte - maybe one of the others can help who has the MSA manual.

[This message has been edited by Marc Smith (edited 03 September 1999).]

#### Marc

##### Hunkered Down for the Duration
Staff member
The problem is that if I was to carry out an MSA study on each 'live' part, I would have to carry out more than 1000 MSA studies - not exactly my idea of fun!
It's not? And all this time I thought this stuff was fun! Umm, here's where you have to use some 'calibration systems sense'. You can classify types and/or brands of equipment, for example. You have 10 B&S 5" calipers? Qualify 1 and 'by similarity' extend the results to the 'brothers and sisters'. Uncertainty for the instrument is expressed in the manufacturers stated tolerance for the instrument.

Roger obviously knows this subject a lot better than I - Comments, Roger?

[This message has been edited by Marc Smith (edited 03 September 1999).]

R

#### Roger Eastin

Marc - you are certainly more of the expert on calibration "common sense" than I am. On the question of where the "6.00" came from on page 37 of the MSA manual: I think it came from the nominal value in Table 5 on page 36 of the instrument considered in the example. The graph on page 38 is helpful here too. I believe they are doing this because they are comparing the linearity of actual measurements to a "best line" line (incorporating bias calculations).

A

#### Alan Greatbatch

Interesting eh!!! On page35 every time process variation is written it has (or the tolerance) written immediately after it. Now to me the process tolerance on a well contolled process that the tolerances(spec limits) are well calculated would be +/-3sigma (6sigma)possibly our figure 6.
In Fig.12 at the top of the graph it states the Process variation = 6.00, maybe it is just one of the assumptions some statistician has made but I would not get too hung up it as in the calculation on page37 it states;

Linearity=[slope] x process variation

%Linearity=100x [Linearity/process variation]

So, I think we can safely say;

%Linearity =100x [slope]

Sorry,I didn't mean to sound sarcastic but some of these calcultions take an hours reading of going round in circles to find some of the figures are unnecessary or meaningless.

PS. I agree with Marc, I would always group common equipments, products, processes for any kind of qualification, approvals or studies.

------------------
Alan

#### Marc

##### Hunkered Down for the Duration
Staff member
Sarcasm is welcome from time to time. We can handle it! We appreciate your post.

Thread starter Similar threads Forum Replies Date
AIAG MSA (Measurement Systems Analysis) Manual 3rd ed. Chapter IV Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
O Problems calculating the observed CP - Page 19, AIAG MSA manual 3rd edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
A Acceptable Criteria for Variable Gage R&R according to the MSA Manual 3rd Edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
Is the 3rd Edition of the MSA Manual current? IATF 16949 - Automotive Quality Systems Standard 2
C AIAG Attribute MSA - Analytical Method - Page 135 of MSA manual 3rd edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 19
J Minitab 14 vs. Excel .xls spreadsheet differences? MSA Manual 3rd Edition Using Minitab Software 4
A Product or Process Tolerence - AIAG MSA Reference Manual 3rd edition page 3 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
D Cp Capability Comparison - Page 19 and 20 of the 3rd edition of the MSA manual Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
T Confidence Interval Of The Bias - MSA Manual 3rd Edition, Page 88 Table 3 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
P Has K1 for GR&R's changed in AIAG 3rd ed MSA Manual? Does it affect outcome of study? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
S Number of Distinct Data Categories - NDC - AIAG's MSA Manual 3rd edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
D Linearity Analysis - AIAG's MSA Manual 3rd Edition - Question Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
D Linearity Analysis - Measurement System Analysis - AIAG MSA Manual 3rd Edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 14
J AIAG's MSA Manual 3rd Edition Attribute Gage Study - Calculating the UCI and LCI Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
Chapter III- Section C of the AIAG MSA manual (3rd Edition) - Tired of analysis? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
Differences between the AIAG's MSA Manual 2nd & 3rd Edition? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
I AIAG's MSA Manual 3rd Edition - A Look at K Values - Auditor Questions Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
MSA for a part Automated and part Manual Inspection Machine IATF 16949 - Automotive Quality Systems Standard 7
B Gage R&R Criteria on page 78 MSA Reference Manual Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
B MSA 4th edition reference manual - Page 120-121 Clarification Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
Definition Equipment definition - What does "equipment" mean in the AIAG MSA Manual Definitions, Acronyms, Abbreviations and Interpretations Listed Alphabetically 1
Simple Navigation Guide for the MSA 4th Edition Manual Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
H Is my MSA Study Spreadsheet okay to AIAG MSA Manual 4th Edition? Using Minitab Software 18
Bias Study-Finding degree of freedom-P 92 of MSA manual 4th Ed. Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
V Excel Templates for MSA Study as per 4th Edition Manual Excel .xls Spreadsheet Templates and Tools 11
N Gauge Performance Curve - MSA Manual Page 181 (4th Edtion) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
Q Using Traceable Standards - AIAG MSA Manual Chapter II, Section B, 1st bullet Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
M MSA Manual asks for NDC higher than 5 - NDC (number of distinct categories) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
Error in ANOVA table in the AIAG MSA manual? Table A4 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
P Is there an Errata sheet for AIAG's MSA Manual Fourth Edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
Manual Formula for p-value Calculation for MSA Analysis Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
MSA Manual 4th Edition, Page 100 - What is wrong in the Linearity graph? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
T Bias Study - Use of 't' statistic - Page 88 item 8 of v4 of the MSA manual Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
T When is GRR (Gage R&R) required? AIAG MSA Manual Version 4 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 19
J New MSA Manual (4th Edition) - June 2010 IATF 16949 - Automotive Quality Systems Standard 1
MSA Reference Manual, Fourth Edition Now Available - June 2010 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 59
E Gage Run Chart Analysis - Page 105 MSA manual 3th edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
E Bias Study - How can I calculate significant 't' value? Page 87-90 of MSA manual Capability, Accuracy and Stability - Processes, Machines, etc. 18
B Operator*part interaction - AIAG MSA manual indicates ANOVA Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
P AIAG SPC Manual (ver.1) Interpretations related to Gage R&R (GR&R) and MSA IATF 16949 - Automotive Quality Systems Standard 8
P MSA Risk Analysis Method - MSA Manual pages 126 and 134 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 9
D What does the entire process range mean? (MSA manual page 73) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
Y Measurement Systems Analysis - Effect on Process Decisions - MSA Manual page 19 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
E MSA Manual says the sum of EV,AV,GRR, and PV cannot equal 100%? Why? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
R "Gauge (Gage) R&R Studies per MSA Manual" - Customer Audit Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 13
D Calculating Bias - Is this method acceptable? MSA manual page 85 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
M D4 constant 2.58 vs. 2.57 - MSA III manual vs. SPC II manual differences Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
F How to use Total Variation based on Process or Tolerance? Page 60 of the MSA manual Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
Scatter plots - A way of making Excel chart scatter plots to page 106 of MSA manual Excel .xls Spreadsheet Templates and Tools 11
T MSA using tolerances - Page 116 of the AIAG MSA manual Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 30