Superfinishing / Microfinishing / Nanofinish

Superfinish, microfinish or nanofinish are the finest surface treatment in the μ-range to improve the roughness. The contact ratio is significantly increased and the sliding surface is optimized by the cross-grinding pattern which creates microscopic oil pockets as usual honing. Ra values ​​down to 0.004 µm can be achieved. 

Technology - Superfinishing

Fifteen years ago honing by stone finishing was the preferred method to achieve precise surface finishing but today more efficient Superfinish (Microfinish honing) has set new standards.


Reduced machining times and precise repeatable finishes are the result of this cost-effective process. Microfinishing achieves a uniform, consistent finish over the entire surface. Superfinishing also called Microfinishing increases the load-bearing area and thus the wear resistance.Material removal is in the range of a few thousandths of a millimeter. 


Superfinishing removes the amorphous material structure, the so-called soft skin. The 0.002 to 0.008 mm thick soft skin layer is created, for example, by high cutting temperatures during stone grinding. The surface treatment is done using superfinishing film. 


Superfinishing film rolls are 15 to 50 m long and available in grain sizes from 0.1 to 100 μm. 

The unwinding of the tape is carried out by a speed-controlled motor. The tape is used once and so the finish result is 100% repeatable

The feed rate of the superfinishing film is adjustable. The belt passes over a contact roller made of elastomer, which is oscillating along the workpiece axis on the surface of the workpiece. 


Continuous supply of new abrasives during the finishing process achieves a uniform surface finish over the entire surface.The interaction of set oscillation frequency, correct feed of the superfinish film and the speed of the workpiece to be machined produces the desired cross hatch surface structure. This way the angle of the honing surface scratch pattern can be varied. The superfinishing is carried out with the aid of coolant or oil.


All units are designed as a machine attachment, so it can easily be mounted onto conventional lathes or other machines


Applications

The Superfinish is the final operation after grinding, polishing or hard turning.
It optimizes the surfaces and reduces the processing time. Thus, pre-machined surfaces can be finished inexpensively. Typical applications include gravure rolls, film rolls, rubber rolls, rocker shafts, bearing seats, sealing surfaces, piston rods, copy rollers, pneumatic pistons, gas spring pistons, valve spools, shifter shafts, ball valves, printer axles, hydraulic cylinders and piston rods, laser engravings.

Materials

Metals, hard chrome and tungsten carbide coatings, cemented carbide, aluminum, copper, rubber, ceramics, plastics and nickel alloys.

Characteristic

Unlike grinding and polishing, Superfinish creates a cross-hatch structure on the surface. 
The method makes it possible to achieve reproducibly high surface qualities on rotationally symmetrical parts with virtually any material composition.

The structure of the surface is improved in the micro range down to 0.004 μm Ra if required.
The superfinishing process allows the user to achieve virtually any kind of surface finish because only roughness peaks are removed.

As a result, no geometry changes occur on the workpiece.
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