1. MEASUREMENT AND INSPECTION
Metrology
Inspection Principles
Conventional Measuring
Measurement of Surfaces
Advanced Measuring
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

2. Measurement & Inspection
Unknown quantity vs. known standard
System of units U.S.C.S. or SI
Numerical value
Accuracy and precision
Inspection (Gaging)
Determine if feature conforms
“Good” or “Bad” (No numerical value)
Gaging – does part meet specification?
Gaging – faster than measuring
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

3. Metrology – Science of Measurement
Derived from the basics
Area
Volume
Velocity
Acceleration
Force
Electric voltage
Heat energy
Length (meter)
Mass (kilogram)
Time (second)
Electric current (ampere)
Temperature (degree Kelvin)
Light intensity (candela)
Matter (mole)
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

4. Manufacturing Metrology
Concerned with measuring a length quantity
Length
Width
Depth
Diameter
Straightness, flatness, and roundness, etc.
Surface roughness
Accuracy
Measurement compared to true value
Precision
Degree of repeatability
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

5. Accuracy versus Precision
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

6. Measuring Instruments and Gages
Precision gage blocks
Square or rectangular blocks
Surfaces are finished to  several millionths
Surfaces are polished to a mirror finish
Graduated measuring devices
Nongraduated measuring devices
Comparative instruments
Fixed gages
Angular measurements
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

7. Measuring Instruments for Linear Dimensions
Micrometer
External micrometer, standard one‑inch size with digital readout
(photo courtesy of L. S. Starret Co.).
Calipers
Two sizes of outside calipers
(photo courtesy of L. S. Starret Co.).
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

8. Measuring Instruments for Linear Dimensions
Vernier caliper
(Courtesy of L.S. Starrett Co.)
Slide caliper, opposite sides of instrument shown
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

9. Dial Indicator
Dial indicator: mechanical gage that amplifies deviations
Applications: measuring flatness, roundness and runout
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

10. Dial Indicator to Measure Runout
Dial indicator setup to measure runout
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

11. Fixed Gages Snap gage GO limit – checks dimension of max MC
NOGO limit – checks dimension of min MC
Plug gage
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

12. Angular Measurements Setup for using a sine bar
Bevel protractor with vernier scale
(Courtesy of L.S. Starrett Co.)
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

13. Stylus Traversing Surface
Stylus‑type instrument
Profile of the surface
Average roughness value
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

14. “Touch‑trigger" probes Sensitive electrical contact
Coordinate Measuring Machine CMM
(Brown and Sharpe Mfg Co.)
“Touch‑trigger" probes
Sensitive electrical contact
Coordinates recorded CMM
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

15. Coordinate Measuring Machine (CMM)
Contact probe
Mechanism to position the probe
Three‑dimensions
Part fixture
Granite table
Part Geometry
Probe contacts the part
Software creates part geometry
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

16. CMM Advantages CMM can perform complex inspection Higher productivity
Less time than traditional manual methods
Greater inherent accuracy and precision
Reduced human error
Flexible – programmable
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

17. Laser Measurement
Interruption time of light beam proportional to diameter D
Light
Amplification by
Stimulated
Emission of
Radiation
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

18. Machine Vision System 2-D systems view the scene as a plane
dimensional measuring and gaging
verifying presence of components
checking for features on a flat surface
3-D vision systems required for contours
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

19. Image Acquisition and Digitizing
binary vision system
light intensity reduced to black or white (0 or 1)
Each set of pixel values is a frame stored memory
(a) dark‑colored part against a light background
(b) 12x12 matrix of pixels imposed on scene
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

20. In-class Problem 01 (45.1)
Two micrometers are used to measure a in gage block. Five measurements were taken with each micrometer. For micrometer A, the five measurements were in, in, in, in, and in. For micrometer B, the five measurements were in, in, in, in, and in.
(a) determine the mean and standard deviation of the error for micrometer A
(b) in-class assignment for micrometer B
(c) which micrometer has the better accuracy
(d) which micrometer has the better precision
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

21. SME Video Measurement and Gaging (28 min)
or (vts_7) Measurement and Gaging
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

22. Time Permitting Problem
Two calipers are used to measure a in gage block. Five measurements were taken with each caliper. For caliper A, the five measurements were in, in, in, in, and in. For caliper B, the five measurements were in, in, in, in, and in.
Determine (a) the mean and standard deviation of the error for each of the devices
(b) which caliper has the better accuracy
(c) which caliper has the better precision
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

23. In-class Problem 03 (45.3)
Design the nominal sizes of a GO/NO-GO plug gage to inspect a ± in. There is a wear allowance applied only to the GO side of the gage. The wear allowance is 2% of the entire tolerance band for the inspected feature.
Determine (a) the nominal size of the GO gage including the wear allowance and (b) the nominal size of the NO-GO gage.
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e

24. In-class Problem 04 (45.5)
Design the nominal sizes of a GO/NO-GO plug gage to inspect a ± 0.18 mm. There is a wear allowance applied only to the GO side of the gage. The wear allowance is 3% of the entire tolerance band for the inspected feature.
Determine (a) the nominal size of the GO gage including the wear allowance and (b) the nominal size of the NO-GO gage.
©2007 John Wiley & Sons, Inc. M P Groover, Fundamentals of Modern Manufacturing 3/e