How super-hard cutting materials revolutionized machining
Horst Lach, CEO of LACH DIAMOND INC., Grand Rapids/MI looks back:
“When I received the first polycrystalline diamonds for testing from the manufacturer General Electric in April 1973, shortly before the Hanover spring tradeshow in Germany, I immediately gave them to our diamond cutting shop for natural diamonds. We wanted to find out how this material could be ground compared to natural diamonds.”
The answer did not take long. The head of our natural diamond cutters, Kurt Wagner (†), an excellent diamond expert, came to me and said: “Boss, we usually do everything for you, but this beastly material is impossible to cut, nothing works…”
Just “Poly” – or what?! Two more days until the start of the tradeshow. We wanted to present this PCD material under the trademarked name “dreborid” for turning interrupted cuts as a tradeshow novelty for aluminum processing.
Someone had an idea regarding “poly“– actually, the diamond grit within a diamond grinding wheel is also “poly“.
No sooner said than done. During grinding with a resin bond diamond grinding wheel, mounted on a small steel grinding machine, the first abrasion tracks or facets became visible.
This was the initial demonstration of grinding a cutting-edge geometry on a polycrystalline diamond.
In retrospect, this first presentation at the Hanover tradeshow in 1973 marked the beginning of a new era of cutting tool technology.
The turbo was ignited. In 1975, cubic crystalline boron nitride (CBN) cutting materials complemented the
programme of super-hard cutting materials for machining high-alloy hardened steel, starting from 58 HRC.
Based on the success of Borazon® CBN grinding wheels since their premiere in 1969, I personally had not anticipated compact boron nitride (CBN) inserts before PCD.
The successful presentation of PCD-tipped saws and milling cutters for the manufacturing of glass fibre reinforced (GRP) circuit boards at productronica in 1977 in Munich showed LACH DIAMANT, the headquarter Germany, the limitations for a further distribution of PCD rotating tools.
The polycrystalline diamond material available to us, had to be cut extensively, piece by piece, tooth by tooth. 25-30 minutes per tooth were quite common, and it had to be with an accurate geometry.
In addition, the PCD manufacturer, like General Electric, had to elaborately segment the pressed PCD blanks by cutting off with diamond saws in order to be able to deliver 60°, 90° cutting edges, rectangles, or squares.
Change, and the truly “sparkling” idea came from LACH DIAMANT.
At the end of 1978, Horst Lach filed a patent application for spark/electro erosion for machining and forming polycrystalline diamond and boron nitride. The second turbo was ignited. An up to 350 times longer tool life than that of previously used carbide tools convinced users all over the world.
Whole industries began to compete in using diamond tools. Ahead of all, in the 1980s, the wood and plastic industry, followed by the automobile and aviation industry. Using PCD tools was fashionable and – since highly economical – virtually a “MUST-HAVE.”
At the next EMO in Hanover, from September 18th through September 23rd 2023, LACH DIAMANT will showcase a complete portfolio of their polycrystalline diamond and CBN tools, developed within 50 years. Already today, a visit to www.lach-diamond.com will be worthwhile your time.