Superfinishing to the Rescue

Increasingly tight tolerances between mating surfaces, especially on wear parts, call for additional processing.


Metalworking is often a violent process. During milling, turning and grinding, the removal of metal creates a rugged, microscopic landscape on the workpiece that resembles mountain peaks and valleys. It is known as an amorphous zone. Increasingly tight tolerances between mating surfaces, especially on wear parts, call for additional processing.

The process called superfinishing, also known as microfinishing, is a secondary operation that follows grinding or hard turning operations as a last surface preparation operation. The process removes surface finish peaks and provides a good load-bearing surface of undisturbed base metal, hardness and structure. Superfinishing is a high precision operation for removing minute amounts of surface material on dimensionally finished parts. The process uses fine grit adhesive particles bounded in stick form for cylindrical work, and in cup or cylindrical form for spherical work.

During superfinishing, a stick oscillates rapidly with a short stroke while the workpiece rotates. The stick may transverse a long piece of material, or the workpiece may throughfeed under the stone. As the abrasive oscillates, the parts rotate or oscillate under the cup or cylinder, producing micro-fine chips.

Shops that use the traditional superfinishing production methods that require a roughing followed by a finishing pass must use two dedicated machines or stop production and reset a single machine.

Read “Multitasking for Micro-Finishing” to learn about a shop who has devised a feed system for its superfinishing machines.

To read about a shop who has developed a retrofitted superfinishing attachment for shops looking to add this capability without purchasing a whole new machine, visit “Bolt-On Microfinishing.” 

 

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Bolt-On Microfinishing

The process of microfinishing or superfinishing, as it's also known, is finding wider application in metalworking. Demands for better performance in rotating components coupled with tighter manufacturing tolerances is leading shops to look at microfinishing as a final process step to achieve low and sub-micron finishes on ground parts.