MSA | What is MSA (Measurement System Analysis)?

MSA | What is MSA (Measurement System Analysis)?


➤ What is MSA (Measurement System Analysis)?

→ MSA is a Measurement System Analysis.
→ It is a statistical tool used to determine if a measurement system is capable or not?


1) Basics of MSA:

→ We use various measuring instruments & gauges to judge the dimensional quality of Incoming, In-Process and Finished Production parts.
→ These gauges and instruments have to be Precise and Accurate to give results of a higher confidence level.
→ To build this confidence, we have to calibrate these gauges/instruments periodically to achieve Accuracy and Precision.

➤ Below measuring instrument has a definite numerical scale to measure the numerical dimensions of the component.

→ E.g., Vernier, Micrometer, Dial indicator, Height Gauges…..

→ Vernier        : Range: 0 – 200 mm L.C: 0.02mm; 0.01mm
→ Micrometer Range: 0 -25; 25 – 50    L.C: 0.01mm; 0.001mm

→ "Resolution" is the smallest unit of measurement that can be indicated by an instrument.
→ "Sensitivity" is the smallest amount of difference in a quantity that will change an instrument's reading. 

→ E.g. a measuring tape have a resolution, but not sensitivity. 
               an analytical balance will have both issues
→ While selecting equipment, the following basic points need to be considered :

  • Range,
  • Least Count,
  • Accuracy and other relevant factors shall be considered.

→ If we have a tolerance of 0.100 of a component, we should use the instrument with Least Count of 0.010 mm. (which means the least count of the instrument should be 1/10th the tolerance range.)



2) Terminologies used in MSA:

→ There are certain terminologies which should be understood for better use of Gauges and Instruments in Measurement System Analysis.

➤ Some of the common terminology used in Measurement System Analysis:

  1.  Precision
  2.  Accuracy
  3.  Bias
  4.  Stability
  5.  Linearity
  6.  Repeatability
  7.  Reproducibility
Terminologies used in MSA (Measurement System Analysis)

3) Why MSA is required?

→ MSA is required to understand the impact of these measurement systems on your operations.
→ It is extremely important in continuous process improvement.
→ We must measure to know where we are.
→ For measurements to be effective, they must be timely, accurate, and precise.
→ Many of our customers, both internal and external, rely on our measurements.


4) The MSA includes:

→The below things are included in MSA:

  1. Standard
  2. Work Piece
  3. Instrument
  4. Personnel / Procedure to use equipment
  5. Environment 
The MSA (Measurement System Analysis) includes

→ Measurement System Analysis deals with analyzing the effect of the Measurement system on the measured value.
→ Its Emphasis is on the effect due to equipment & personnel
→ We test the system to determine the numerical values of its statistical properties and compare them to Accepted Standards



5) The objective of Measurement System Analysis:

→ To determine how much error is in the measurement due to the measuring process itself.
→ Quantifies the variability added by the measurement system.
→ Applicable to attribute data and variable data.
→ Conducting an MSA reduces the likelihood of passing a bad part or rejecting a good part.

6) When to Use MSA:

→ On the critical inputs and outputs prior to collecting data for analysis.
→ For any new or modified process in order to ensure the quality of the data. 


➤ Who Should be Involved in MSA Study:

→ Operators
→ Inspectors
→ Engineers who measure and makes decisions about these measurements should be involved in this study

👉 Note: MSA is an analysis of the Measurement Process, not an analysis of the people !! It comes before SPC.



7) Types of MSA Study:

  1. Variable GR&R Study
  2. Attribute GR&R Study