Trochoidal milling is a relatively new cutting strategy that involves the overlapping of circular toolpaths with linear movement. It is well-suited for difficult-to-machine materials and thin-walled components.

The small contact angle on the tool reduces heat generation during machining and lowers thermal stress, which increases tool life. The endmill is fully utilized over the entire flute length. As a result, wear is evenly spaced over the full cutting edge, which also contributes to longer tool life. In addition, high metal-removal rates can be generated even on low-powered machines, and wear is reduced during full slot milling.

Emuge Corp. has just introduced a line of solid-carbide endmills designed specifically for trochoidal milling. The tool manufacturer reports that the line allows the user to increase removal rates more than 30 percent. It also enables a high axial DOC—up to 4 diameters deep, according to Emuge. The series was developed specifically for advanced milling strategies made possible by CAM software, which optimizes the calculation of milling paths and eliminates unproductive tool motion.

Emuge trochoidal endmills with chip-breaking geometry. Image courtesy of Emuge.

Dan Doiron, Emuge milling products manager, said the line's new chipbreaker geometry reduces axial pullout force. It also minimizes the risk of chip buildup in pockets. The resulting smaller chips can be easily removed with compressed air or coolant.

"When the entire flute length of an endmill is utilized, as in trochoidal milling for the purpose of roughing, the next operation would normally be to select a nonchip-style mill to finish a wall, for example," he said. "However, with our staggered chipbreaker geometry, the best of both designs are incorporated. Thus, using the same tool can enable aggressive cutting speeds followed by a conservative final finish pass."

Emuge's trochoidal endmills feature variable spacing, variable helix angles and improved microgeometry to minimize vibration, the company reports, along with new, high-performance coatings of TiN, TiAlN and AlCr, and a submicrograin-carbide substrate.

The endmills are available in two cutting geometries: Jet-Cut (for both roughing and finishing in steel applications) and Coolant-Through TiNox-Cut (for process-reliable roughing in tough materials such as Inconel, titanium and stainless steel). Standard and long-length rougher/finishers with flute length-to-diameter ratios of 2:1, 3:1 and 4:1 are available for applications in a range of materials.

For more information about Emuge Corp., West Boylston, Mass., visit www.emuge.com or call (800) 323-3013.