Chapter 12: Angle and Surface Measurement

1
Chapter 12 Angle and Surface Measurement

• Overview
• Square Measures
• The protractor, Sine Bars and Plates
• Surface Metrology
• Surface Evaluation, stylus method
• Surface Assessment and Texture Specimens

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Square Measurement

• Use the varieties of hardened-steel
• The combination square
• the square and part are on the
• slide the square into with the part feature
• use paper, magnifying glass, light to observe
  the
• Compare the part to a
• Calibrate a square compare the square with a
  
• another type the cylindrical square
• place the square contact with the part feature
  and turn it until ? top curve ? number
  5.08µm per 15.24cm
• The level when the reference planes are , the
  bubble is

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Square Measurement
4
Square Measurement
5
The Protractor, Sine Bars and Plates

• The Protractors
• Use to measure angles the universal bevel
  protractor
• Applications determine the angle or degrees in
  any arc
• Sine Bars and Plates
• Two types of sine bars or
• Three sources of error when using the sine bar
  geometric, mechanical and setup
• How to use measure the ?table
• Comparison measurement with sine bar
• Types of sine bars
• Sine blocks lt sine plates ltsine tables wide (no
  distinctions)

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The Protractor, Sine Bars and Plates

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The Protractor, Sine Bars and Plates
8
The Protractor, Sine Bars and Plates
9
Surface Metrology

• Surface metrology surface topology and
  surface (finish)
• The of the surface , , and
• is the direction of the asperities

10
Surface Evaluation Stylus Method

• To evaluate surface finish compare visually and
  by feel with roughness comparison specimens
  having various surface finishes
• Tools microscopes, interferometry, stylus
  instruments
• Stylus operates like a phonograph pickup
• Problem
• distortion ratio? exaggerate hight / spacing
• Small tip ?scratch the surface
• Types of stylus
• True datum move the across the part along a
  ?surface assessment the part form
• Surface-datum A or slides along the
  ? the surface datumlocus of the skids
  center

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Surface Evaluation Stylus Method
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Surface Evaluation Stylus Method
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Surface Assessment and Texture Specimens

• Numerical values for assessment
• Arithmetic Average Roughness RA ?yi/n
• Others (reading)
• Surface Texture Specimens
• The precision reference specimen calibration
• The roughness comparison and pilot specimens
  and of surfaces