MSA When an Instrument Measures More than One Parameter

ADSJT

Quality Engineer
#1
I am preparing for MSA studies on an instrument that measures density and specific gravity. The question was asked whether we need to do two studies, one for density and one for specific gravity. The instrument prints both results for each test. Some feel that it is not necessary to run separate tests when specific gravity can be calculated once density is known. I would like to purchase separate standards and run separate tests, at least for the initial set of studies. I need to justify allocating the resources to do that. I am also flexible enough that I will adjust my thinking if there is justification for relying on the instrument's conversion between the two.
 
Elsmar Forum Sponsor

Ninja

Looking for Reality
Trusted Information Resource
#2
MSA studies (I assume by this you mean Gage R&R) are for the test method...not the equipment.

That said, Specific gravity and density are pretty much the same thing...but wildly different all the same.
One is for g/cc of a solid (density) and one is for g/cc for a liquid (Specific Gravity).

One measuring a solid, the other a liquid...you're pretty much in for two GRRs regardless.

Density of a liquid is a misnomer. Specific Gravity of a solid is a misnomer.
When you measure a solid, the density reading counts, the Sp.Grav doesn't. And vice-versa.

Run the GRRs for the things you will use the equipment for...if both, GRR both...liquid and solid.
 

Ninja

Looking for Reality
Trusted Information Resource
#3
And BTW...the standard for Specific Gravity is water...at 1atm and 25degC. Don't buy it, get it from the tap...unless your spec is ridiculously tight...
 

Eredhel

Quality Manager
#4
Had a print call out for "Specific Gravity" on a product line once, the engineer removed it before we started running them. I've learned a bit more today :).
 

ADSJT

Quality Engineer
#5
Thank you Ninja,

I am not purchasing water, I plan to purchase standards that are traceable to specific readings. I cannot use our product for the test that I am currently running. And by MSA, I mean GR&R ,Accuracy, Linearity, Matching and Correlation, and Long Term Stability.
 

ADSJT

Quality Engineer
#6
It is my understanding that specific gravity has no units because it is a ratio of the density of a substance to the density of a standard. It is also called relative density. That is why the question came up regarding using the results of the density studies to also cover specific gravity.
 

Ninja

Looking for Reality
Trusted Information Resource
#7
It is my understanding that specific gravity has no units because it is a ratio of the density of a substance to the density of a standard. It is also called relative density. That is why the question came up regarding using the results of the density studies to also cover specific gravity.
You are correct in this...but the "standard" being water at STP...which is 1.000 g/cm3...the specific gravity ends up being correct either with or without units.

THe specific gravity of Kerosene at 60degF is 0.820 ...that means both that it is 82% the "density" of water at STP...and that it is 0.820 grams/cm3

Formally, it is a unit-less figure...but I rarely dress up that much :cool:

With GRR on that type of equipment being so easy and quick to run...I would just run it and remove all question.
 

Ninja

Looking for Reality
Trusted Information Resource
#8
I am not purchasing water, I plan to purchase standards that are traceable to specific readings.
A good move...but for linearity you'll want to use water as well.

Make sure you understand the full formality behind sample prep of your standards...temperature and purity matter...to the degree dictated by your needs in your spec range...
 
Thread starter Similar threads Forum Replies Date
C MSA (Measurement System Analysis) - Instrument Selection Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
B For a measuring instrument, should MSA be done first or the Capability studies? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
Ron Rompen MSA on automated measurement system - Multiple Step Vision System Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
G MSA check list to audit IATF 16949 - Automotive Quality Systems Standard 8
R MSA for ATE (Automatic Test Equipment Embedded Software) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 9
Bev D MSA Tools Misc. Quality Assurance and Business Systems Related Topics 3
R MSA studies for Heat Treatment Equipment Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
C Industrial scales and MSA (IATF 16949 requirement 7.1.5.1.1) IATF 16949 - Automotive Quality Systems Standard 30
M Difference between MSA and MSE? General Measurement Device and Calibration Topics 1
M Test method validation - Is MSA (MSA1, MSA2, MSA3 and linearity) a good solution? Medical Device and FDA Regulations and Standards News 1
A MSA results differences - Supplier results vs. My results Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
R Preliminary MSA and Sockets' correlation Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
I MSA requirement for 5 Micrometers + CP changes need customer approval? IATF 16949 - Automotive Quality Systems Standard 2
T Correct MSA study for an automated camera system which makes attribute inspection Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
Bev D MSA Misc. Quality Assurance and Business Systems Related Topics 46
Emran.mi Measurement system analysis - Can you help me about implementation MSA for CMM device Manufacturing and Related Processes 2
N MSA Study for a Leak Testing Device Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
N Justifications for not performing MSA (Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
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
Prashant G MSA Study - AS 9100 and and our customer want us to do MSA study for their parts dimension Reliability Analysis - Predictions, Testing and Standards 4
D Compression Spring Force MSA Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
E MSA Study on MTS dynamic rate measurements Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
A The FILE recommended by AIAG MSA 4ed for LINEARITY Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
S IATF 16949 Audit MSA IATF 16949 - Automotive Quality Systems Standard 10
C Do Calibration Reference Standards require an MSA study? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
G MSA Type 1 - Cg and Cgk ranges Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
O MSA Study for a steel ruler Manufacturing and Related Processes 6
P IATF 16949 MSA Studies for CMM machines IATF 16949 - Automotive Quality Systems Standard 3
B 7.1.5.1.1 MSA for inline dimension vision inspection equipment IATF 16949 - Automotive Quality Systems Standard 5
G MSA on a Counting System Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
C AIAG's IATF 16949 section 7.1.5.1.1 - Torque MSA Requirement Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
S IATF 16949 7.1.5.1.1 Measurement System Analysis (MSA - Die casting) IATF 16949 - Automotive Quality Systems Standard 5
J MSA on Part Specific Attribute Fixtures Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
G ANOVA GR&R: Minitab vs AIAG MSA results Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
S Test Method Validation or MSA for Batch Manufacturing Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
S MSA on a process using different fixtures Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
B Camera Vision System Measurement System Analysis (MSA) Reliability Analysis - Predictions, Testing and Standards 3
D Cp/Cpk on Gages for MSA (vs. Cg/Cgk) Capability, Accuracy and Stability - Processes, Machines, etc. 21
L Number of Distinct Categories" or NDC Calculation in MSA Studies Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
Q Doing an MSA on a Climatic Chamber Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
L IATF 16949 7.1.5.1.1 Measurement System Analysis (MSA) - Visual Inspection IATF 16949 - Automotive Quality Systems Standard 14
C MSA for Non Manufacturing - Design Validation, Characterization and Qualification Lab Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
C PPAP Rejection for "MSA-GR&R are not using the latest AIAG format" APQP and PPAP 9
C MSA (Measurement System Analysis) - Dimension Selection Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
P Frequency and Sample Size Requirements for an MSA Studies Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
A Automated Measurement Machine MSA - Small Parts Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
Crimpshrine13 MSA for a part Automated and part Manual Inspection Machine IATF 16949 - Automotive Quality Systems Standard 7
S MSA (Measurement System Analysis) - Process Tolerances Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 9
B How to do an MSA on an Automated Torque / Angle System Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
B How to perform a MSA - GRR (Gage R&R) A&R/ANOVA Vs GUM/VDA Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1

Similar threads

Top Bottom