The new CoroMill Plura compression end mill for composites from Sandvik Coromant is certain to be of great interest to any manufacturer machining carbon-fiber reinforced polymers. The innovative CoroMill Plura tool combines positive and negative helix design to "compress" the top and bottom of the component edge. This minimizes any potential for delamination, a common defect when machining CFRP and several other types of engineering composites using higher helix cutters.

The new Plura end mill has been designed for edge milling applications on workpieces with a minimum thickness of 6mm. It features optimized micro geometry that offers six effective cutting edges for achieving a surface finish (Ra) of well below 0.0001" (4µm), in combination with high material removal rates. Users should keep the split-line in the middle of the material for best results. Also, remember that when the tool cuts fibers going against the grain on the top or bottom surface there is potential for more splintering than when the tool cuts along the fiber direction.

Conventional up-milling strategies are recommended as these typically deliver less vibration. Among the cutting data users can expect to see is cutting speeds of 656-1312 ft./min. (200-400 m/min), and feed rates of 0.001-0.002"/tooth (0.03-0.06mm/tooth) for roughing or 0.008-0.0015"/tooth (0.02-0.04mm/tooth) for finishing.

Aside from the aerospace industry, other sectors set to benefit from the new end mill include motorsport, marine, wind energy and leisure, essentially any company machining CFRP that is looking to enhance material removal rate and tool life while at the same time achieving minimal delamination of layers.

The CoroMill Plura compression end mill for composites makes use of GC1630 grade for extended life, and comes in diameters ranging from 0.24-0.63" (6.0-16.0mm), and lengths (total) from 2.99-3.94" (76 to 100mm).