New coating called as significant as intro of hard milling

With the proper tooling, equipment and setup, hard milling 60-HRC tool steel is no sweat., however, when milling harder materials that are generally ground or sinker-EDMed。That’s no longer the case with the introduction of diamond-coated tools. “From Makino’s perspective, we see this tooling development probably being as significant as the introduction of direct hard milling in the mid-1990s,” he said, noting that milling carbide with carbide tools previously achieved a 10 to 20 percent success rate.

the coating’s hardness is about 100 GPa, or 9,000 HV. “It’s very close to a single-crystal diamond in terms of hardness.”

Because the cutting force when milling carbide is about three times greater than when milling 60-HRC tool steel, applying a UDCB endmill requires a rigid machine to minimize vibration and an inclined or helical approach to provide gradual cutter entry into the workpiece.

“We found the helical feed to be more reliable because the cutting force is more even on the approach,” Hay said, noting the feed can remain constant throughout the cutting cycle. He added that an even cutting force helps prevent damage to the brittle workpiece, tool substrate and coating.

“Obviously, with three brittles, we need to get everything just right,” Hay said.