Kennametal recently released its newest helical milling cutter, the Harvi Ultra 8X.

Using a 95 mm (3.74 in.) axial depth of cut, 20 mm (0.78 in.) radially, and a feedrate of 423 mm/min (16.65 ipm), the 80 mm (3.15 in.) diameter Harvi Ultra 8X  helical milling cutter from Kennametal recently worked through a difficult aerospace superalloy. Tim Marshall, senior global product manager for indexable milling, has tested the Harvi Ultra 8X with a variety of customers, pushing the limits of the new cutter on everything from 15-5 PH to cast iron to Aermet 100 (high strength steel) and seeing outstanding results with each.

“Kennametal developed the Harvi Ultra 8X to meet two distinct needs,” Marshall says. “The first came from the aerospace industry, which thanks to the large numbers of aircraft being built today requires the highest metal removal rates possible but still achieving excellent tool life. At the same time, machine tool builders and users alike are asking for tools able to withstand higher cutting speeds but generate lower machining forces, so as to reduce wear and tear on machine components during extreme cutting conditions. The new Harvi Ultra 8X does all that, and a lot more besides.”

Marshall said it was designed to predictably remove 20 cubic inches (328 cm3) of Ti-6Al-4V each minute while attaining 60 minutes of tool life per cutting edge. To do this, Kennametal combined a number of innovative technologies into this cutting tool solution including a double-sided yet positive rake insert, a unique AlTiN+TiN PVD coating that provides robust resistance to thermal fatigue, a higher quality steel for improved stiffness and rigidity under high cutting forces, a unique BTF46 (bolt taper flange) connection that provides deflection resistance and a variable helix design that breaks up the harmonics that lead to chatter, further improving tool life, part quality, and throughput.

“We’ve optimized everything about the Harvi Ultra 8X,” said Marshall. “The flutes and the coolant nozzles assure maximum chip flow, something that’s very important when you’re removing this much material—without it, the chips get jammed up and you’re facing catastrophic failure. Our KCSM40 grade has proven to be a top performer in high-temp alloys, but we also offer several equally excellent grades for other workpiece materials.”