Cutting Tool Engineering
July 2011 / Volume 63 / Issue 7

A Polished Cut

By Alan Richter, Editor

Monocrystalline diamond tools can be effectively applied to produce high-polished surfaces on nonferrous materials, including metals and synthetics such as polycarbonate and polyvinyl chloride thermoplastics. However, conventional MCD tools require a specialized, highly accurate machine and take about 2 hours to set up, according to Duane Drape, national sales manager for HORN USA Inc.

Therefore, the toolmaker offers MCD-brazed inserts that can be set up in about 15 minutes and applied on traditional CNC machines, Drape noted. “It’s a braze, but not a traditional braze,” he said. “It has to be done under an extreme vacuum setup.”

MCD vs PCD.tif
Courtesy of HORN

The cutting edge of a monocrystalline diamond (left) and a polycrystalline diamond at 1,000× magnification.

The MCD inserts can impart surface finishes finer than 1µm Rz on specialized equipment. While that fine a finish is not achievable using the MCD inserts on standard CNC machines, Drape indicated that HORN achieved an 11µm Rz finish on brass and 14µm Rz on aluminum using standard machines. “Both those surface finishes are absolutely incredible,” he said, adding that they would be perfectly acceptable for many parts.

The tools, which are produced by the German company H10 Technische Diamanten using HORN inserts, can be retipped five or six times, Drape added. “A retipped insert will be exactly the same as a brand new one.”

For more information about HORN USA Inc., Franklin, Tenn., call (888) 818-HORN or visit CTE

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