FriCSo’s polymer lapping devices, which are used with off-the-shelf abrasive pastes, create performance-enhancing surfaces and reduce surface roughness.

• surface roughness reduced from Ra 0.3 µm to ≤0.03 µm (ISO N5 to N1) in
  single step
• surface hardened increased to as much as 1100 Vickers to depth of 1 µm

FriCSo’s polymer-based products are deployed on current superfinishing machines in the existing production lines.

 
Oil retention
FriCSo surface treatment has been proven to dramatically reduce the friction between moving parts demonstrated by the following test and graph. The graph compares the sliding distance until seizure during a block-on-ring test (linear contact surface) of two hard steel elements with various finishes. The test was run using a single drop of oil at a sliding velocity of 0.65 m/s and a normal load of 400 N.

 

 As shown, the commercially ground surface seized after 200 m. The surface treated with FriCSo’s polymer lapping ran for 30,000 m without seizing, after which the test was stopped. The picture below is of the block after the test.
 

The commercially ground surface shows signs of wear and abrasion, which dramatically decrease performance and efficiency. The area treated with FriCSo polymer lapping shows some oxidation at the line of contact, but clear evidence of hydrodynamic lubrication with no wear and no abrasion.

Durability
Third-party trials have firmly established the durability of the FriSCo surface treatment under extreme conditions. The picture below shows production parts of a hydraulic pump that were superfinished, then subjected to 1.2 million cycles at 372 bar with sliding velocity of 2,400 RPM, at 180°F. Severe pitting of the surface is clearly visible.

 

The picture below shows the same parts, but finished with FriCSo's polymer lapping. The parts were subjected to the same tests under the same conditions. The surface appears as if new. No signs of wear are visible, clearly demonstrating the durability of FriCSo's polymer lapping treatment.
 

In other tests, the FriSCo treatment continued to function as new at up to 400 bar, at up to 250°C, and in excess of 1.2 million cycles at several thousand RPM.

Flatness
Polymer lapping improves surface topography (Ra, Rz, Rpk) and the Bearing Area Curve (BAC), as shown by the tests below, performed by a perspective customer.

Comparison of Commercial Superfinishing and FriCSo polymer lapping

Description	Height histogram	Average roughness (Ra)	maximum height of profile (Rt)
Commercial washer, ground as in the production process		0.42 µm	3.3 µm
Commercial washer, superfinished as in production process		0.07 µm	0.25 µm
Commercial washer, after FriCSo polymer lapping		0.02 µm	0.13 µm

 

The following actual test result shows the bearing area curve before and after polymer lapping. 

 

Hardness
Polymer lapping significantly increases the hardness of the outer layer of steel of the work piece. A pliable polymer surface and off-the-shelf abrasive paste are used in FriCSo’s polymer lapping. Under pressure, abrasive crystals become lodged in the polymer and sharp vertices break off. Because the crystals are constantly rotating (unlike in a cast-iron substrate, where the same crystal face always faces the work piece), the sharp vertices are eventually all removed and the crystal becomes nearly round. When the pressure of lapping is transferred through the very small contact area of the rounded crystals, the outer surface of the work piece is compacted.

Professor Skvartzov of the Moscow Institute of Technology measured the hardness of a polymer lapped work piece. 

 

 
As shown in the graph, surface hardness has increased from about 500 Vickers for the bulk material of the work piece to about 1,100 Vickers down to a depth of <1 µm, a very significant improvement in the surface.

 

 

Performance Improvement
The effect of the FriCSo surface treatment is demonstrated by the following results obtained by an independent laboratory for a prospective customer.

Block on Ring Test Showing Characteristics of FriCSo Surface Treatment

Description 

This graph shows the coefficient of friction obtained by sliding a steel block over a commercially superfinished piston pin. The load was increased step-wise from 445 N (100 lbs) to 2220 N (500 lbs), the sliding velocity fixed at 20 RPM.

 

Results

As shown in the graph, each time the load was increased, the coefficient of friction increased dramatically, indicating wear, abrasion, and wasted energy.

 

 

 

 

Description 

This graph shows the results of the same block and ring test after polymer lapping of the ring.  

 

Results

 

 

To introduce polymer lapping into your product line, replace the stones on your superfinishing machine with a FriCSo polymer lapping tools. 

 

Polymer lapping is completed at the same throughput as superfinishing. Polymer lapping is environmentally clean: no toxic materials are used and no hazardous wastes are produced.