Surface Texture Symbols by h4e2hmEd

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									Surface Texture Symbols

       CHAPTER 12
  INSTRUCTOR: M.YAQUB
12.22 Surface Roughness, Waviness, and Lay
• The modern demands of the automobile,
  the airplane, and other modern machines
  (heavier loads, higher speeds with less
  friction) need for accurate control of
  surface.
• The system of surface texture symbols
  recommended by ANSI/ASME.
    Surface Texture Symbols
• Not all surfaces can be finished because
  of cost constrains. Few surfaces requires
  special surface finish and should indicate
  on drawing by using surface finish symbol.
Definations
Roughness CLA or Roughness height (Ra)
Average of roughness height over a certain length
Roughness-width Cut off
The length over which roughness is average

Roughness Width:       Horizontal distance between two similar point
Waviness Width:    Overall width
Waviness Height:   Overall height
Lay Direction:     Mark of machining on surface

Flaw: Defect on material surface
Surface texture symbol
       Additional Information
• Usually all information are not required.
  Only roughness height and machine
  allowance is important. In this case basic
  symbol is used.
• Roughness height in mm or in m inch. All
  other in mm or inch.
Example

								
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