CoroDrill 854 and CoroDrill 856 drills are for making holes in composite materials and were developed to withstand the harshest carbon-fiber reinforced plastics (CFRP) and aluminum stacks. Producing holes in such materials demands unique geometries for a required tolerance and quality because delamination and splintering are common problems. Combining CFRP with a stacked materials, such as aluminum, adds another dimension to the problem because the two materials vary in machining techniques.
CoroDrill 854 improves hole entrance and exit quality on high fiber content materials. Use CoroDrill 854 where splintering or fraying is a problem, while there is more benefit with CoroDrill 856 when delamination is proving difficult in resin-rich materials. The CoroDrill 856 drill uses small point angles and high rake angles to improve hole quality and reduce axial forces, particularly critical on thin-walled surfaces. Both designs help eliminate burrs and enhance surface finishes. Diameters span from 0.157 in. (4 mm) up to 0.500 in (12.7 mm), the standard N20C solid carbide versions with diamond coating are available as stocked items.
Sandvik Coromant USA
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