Mechanical Surface Finishing Processes

Chapter 16

Finishing vs other final processes

• Finishing processes are not intended to significantly change the dimensions of the product.

• Finishing processes are intended to:– Achieve closer tolerances– Provide a protective coating– Improve the appearance of the part

Surface Preparation

• Deburring– Hand– Barrel and vibratory– Belt or disk sanding

• Stripping/Cleaning– Dry and wet blasting– Power Brushing– Ultrasonic cleaning

Smoothing Operations

• Honing– Abrasive stones– Finish auto cylinder walls

• Superfinishing– Chrysler Corp version of honing

• Lapping– Removes less than 0.0005 inch (0.01

millimetre)

Polishing

• Fine scale abrasion

• Smearing– Push high points over into the low places to

smooth out the surface.

Buffing

• Used to produce a high luster

• Remove scratches from the surface

• Often precedes polishing

• Gives a smooth lustrous surface, Polishing puts the shine on the part.

Burnishing

• Brush the surface with a wire brush

• Uniform smooth finish

• Dull surface

Ballizing

• Forcing a ball through a hole slightly cut undersize.

• The ball passing through the hole– Hardens– Sizes– Smoothes

Bearizng

• Used on larger holes than ballizing

• Roller bearings are mounted similar to honing stones– Sizes – Work hardens the hole.

Finish Specification

• Information needed– Process of final manufacturing operation– Waviness, roughness and lay required– Process of the surface prep or finish– Type of coating to be applied– Process to apply the coating

• See page 324