Diamond-Coated End Mills Yield Impressive Gains
Buyer's Guide: Machining Accessories

As with other equipment, state-of-the-art CNC machinery is only as good as its weakest link. In the machining of abrasive materials such as graphite, that weakest link can be a cutting tool. "Bare" carbide tools wear out quickly in graphite, and traditional coatings can be less than satisfactory. Pleasant Precision, an Ohio-based manufacturer of the Round Mate Moldmaking System, found graphite was particularly hard on tool life. This meant there was machine downtime, and jobs couldn't be run unattended.

After trying other coated tools with limited success, Ron Justice, production manager for Pleasant Precision, came across an advertisement for diamond-coated tools by CVD Diamond Corp. He took advantage of an introductory offer and found that the tools lasted long enough to machine as many as 14 electrodes with one tool. After a few more trials, Justice was confident a machine could be set up and run through the night, with multiple electrodes or even multiple jobs.

"The results are consistent with our other customers," says Joe Brennan, president of CVD Diamond Corp. "Diamond is the hardest material known to man, so it is the best material there is for abrasion resistance. A material such as graphite is ideally suited for diamond, since abrasion is the dominant wear mode."

Diamond is also reported to have excellent heat spreading capabilities, so it runs significantly cooler than carbide, helping to maintain the edge and keep a tool sharp.

"Since the accuracy of the geometry is our first concern, we've performed thorough checks on the shapes of the tools," says Justice. "We have found the geometry to be so consistent that we no longer have to qualify every tool."

Justice adds, "The availability of the tools we need has been excellent, and we have found that even though the price of the tools seems high, the cost of producing electrodes has been significantly reduced."


CVD Diamond Corp.
London, ON, Canada
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