SURFACE FINISH COMPARISON CHART

SURFACE FINISH COMPARISON CHART
RA is the arithmetic average deviation of the surface valleys and peaks and is often used to specify the roughness of a machined surface. RMS is the root mean square average of the profile height deviations from the mean line of the surface and is mostly used for optical surfaces.
The term Micro means millionth. So 1 micrometer is 1 millionth of a meter, or .000001 meter. Likewise 1 microinch is 1 millionth of an inch, or .000001".   The term "Micron" refers to 1 millionth of a meter, which is also equivalent to 1 thousanth of a millimeter (.001 mm), and is represented by the greek symbol μ. Ra microinch ( μ" ) is basically the same as the CLA scale, or centerline average.                                                                 
Some Useful Conversions:
Inch = " or in       1 microinch (μ") = 0.0254 micrometers (or microns)
Micron = µ    1 microinch (μ") = 0.0000254mm
Micro Inch = µ"    0.001" = 0.0254mm
Micrometer = µm     
Millimeter = mm     
Below are equivalent values on various surface measurment scales, and the manufacturing methods capable of producing these finishes.
New ISO scale numbers   1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.
RMS Microinches ( μ" ) 0.5 1.1 2.2 4.4 8.8 17.6 35.2 64.3 137.5 275 550 1100 2200
RMS Micrometers ( μ m ) 0.013 0.027 0.055 0.11 0.22 .44 .88 1.6 3.44 6.88 13.75 27.5 55
CLA or Ra microinch ( μ" ) 0.5 1 2 4 8 16 32 63 125 250 500 1000 2000
Ra micrometer ( μ m ) 0.012 0.03 0.05 0.1 0.2 0.4 0.8 1.6 3.2 6.3 12.5 25 50
Sand Casting                          
Hot Rolling                          
Forging                          
Permanent-Mold Casting                          
Investment Casting                          
Extruding                          
Cold Rolling                          
Diecasting                          
Flame Cutting                          
Sawing                          
Planing                          
Drilling                          
EDM                          
Milling                          
Laser Cutting                          
Reaming                          
Broaching                          
Turning and Boring                          
Tumbling                          
Roller Burnishing                          
Grinding                          
Honing                          
Electro-Polishing                          
Polishing                          
Lapping                          
Superfinishing                          
About Us

Advanced Integrated Technologies is essentially a manufacturing service company with two major divisions. The resistance welding and reflow soldering tool division grew out of our early work building micro tools for Hughes Aircraft. About the time that Microsoft was turning computers into a household item, computer hardware manufacturers were looking for companies to build reflow tools used in the assembly of hard drives and other components.

10 ars
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