Profile Cutting Advancement

From time to time cutting tool manufacturers make advancements to their technologies that allow cutting tool users to increase productivity and profitability. Circle segment end mill technology, which is used to make cutting tools for profile finishing on a milling machine, is one significant case in point.

Back about 20 years ago, when my shop made a line of motorcycle parts for custom bikes, I shaped curved profiles into billet aluminum using ball end mills. After recently learning about circle segment end mills, aka barrel cutters, I immediately realized these tools are winners. They certainly can help makers of aerospace parts, medical devices and molds — just to name a few benefactors.

Compared to profiling with a ball end mill, a circle segment end mill can produce better surface finish while reducing the cycle time by as much as 95%. This is possible because a circle segment cutter has a larger radius on the cutting edge than a similarly sized ball end mill. Plus, circle segment end mills retain a form that allows it to reach into a pocket. The tool and toolholder can get close to the cut, which reduces deflection in the setup and improves system accuracy. Profiling with a cutter that has a convex cutting edge produces a crest between adjacent cuts on the workpiece. The larger the radius of the cutting edge, the smaller the crest, and the better the surface finish.

Alternatively, you could use a bigger step-over value between adjacent tool paths and reduce cycle time. The CNC code that guides these cutters has a large part to play mitigating any potential production trade-offs. Success relies on programming capable of optimizing the operation for increased profitability.

That said, not all CAM software systems support circle segment tools.

EMUGE-FRANKEN USA and OPEN MIND Technologies, two early adopters of circle segment end mills and the CAM software needed to appropriately utilize them, remain among the companies leading the development and implementation of this technology. To ensure optimization of code generation for their circle segment tools, EMUGE works closely with CAM software developers such as OPEN MIND (hyperMILL) and CNC Software (Mastercam).

EMUGE offers four circle segment end mill options: barrel, taper, oval and lens. Each is optimized for a particular profile application (see illustration). The tools can be used to cut some profiles on three-axis machines, but they really shine on a five-axis machining center.

At EMUGE’s Advanced Productivity Center in West Boylston, Massachusetts, the company offers two services for shops:

EMUGE CNC Programing Assistance. This service offers shops programming assistance and process recommendations, along with optimized tooling recommendations.

EMUGE Test Cuts Program. Beside circle segment end mills, EMUGE makes a broad range of milling tools. The company can develop a milling program from roughing through circle segment finishing for a customer’s particular workpiece; and then test it on advanced five-axis machines at the company’s North American headquarters in West Boylston, Massachusetts.

In the next issue I will go over some real-world examples to show how these tools can improve your bottom line.

about the author: Brandt Taylor is the owner of Taylor Engineering, a Berlin, Massachusetts- based machine shop. He can be reached via email at gbrandttaylor@gmail.com.

images

filename: Four_Circle_Segment_End_Mill_Forms.jpg

credit: EMUGE-FRANKEN

Caption: EMUGE illustration shows four circle segment end mill options: barrel shape, taper form, oval form and lens shape.

Optional image filenames: Einsatz Kreissegmentfräser 250516-01.jpg, Einsatz KSF Tonnenform 3542L 151013-01.jpg, industries-turbine_teaser_circle-segment.jpg, and news-circle-segment-canadian-metalworking_defaultteaser.jpg