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

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

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

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

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

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

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

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

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

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

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

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

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

“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

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

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

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

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

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 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 1 1 1 1 1 1 1 1 0 1 1 0 1 1 1 1 1 1 1 0 0 1 1 0 1 1 1 1 1 1 0 0 0 0 0 0 1 1 1 1 1 0 0 0 0 0 0 0 1 1 1 1 1 0 1 0 0 0 0 0 1 1 (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

In-class Problem 01 (45.1) Two micrometers are used to measure a 1.0000 in gage block. Five measurements were taken with each micrometer. For micrometer A, the five measurements were 1.0001 in, 1.0003 in, 1.0000 in, 1.0001 in, and 1.0003 in. For micrometer B, the five measurements were 1.0002 in, 0.9999 in, 1.0001 in, 1.0000 in, and 0.9999 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

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

Time Permitting Problem Two calipers are used to measure a 2.000 in gage block. Five measurements were taken with each caliper. For caliper A, the five measurements were 2.002 in, 2.003 in, 2.003 in, 2.001 in, and 2.006 in. For caliper B, the five measurements were 2.002 in, 1.999 in, 2.001 in, 2.000 in, and 1.997 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

In-class Problem 03 (45.3) Design the nominal sizes of a GO/NO-GO plug gage to inspect a 1.500 ± 0.030 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

In-class Problem 04 (45.5) Design the nominal sizes of a GO/NO-GO plug gage to inspect a 30.00 ± 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