Sandvik Coromant’s CoroMill Plura compression end mill for composites combines a positive and negative helix design to “compress” the top and bottom of the component edge.
The company claims this minimizes any potential for delamination, a common defect when machining carbon-fiber reinforced polymers (CFRP) and 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 6 mm. It features optimized micro geometry that offers six effective cutting edges for achieving a surface finish (Ra) of well below 0.0001 in. (4 µm), 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 in./tooth (0.03-0.06 mm/tooth) for roughing or 0.008-0.0015 in./tooth (0.02–0.04 mm/tooth) for finishing.
