“Automotive manufacturers are increasingly adopting aluminium parts to help reduce vehicle weight and improve fuel efficiency,” says Aaron Howcroft, global product manager at Sandvik Coromant. “These latest drills with grades optimised for ISO N materials offer a host of benefits, including high reliability, enhanced precision, low cost-per-hole, longer and more consistent tool life, high repeatability and improved process security.”
While both CoroDrill 400 and CoroDrill 430 are available in the Sandvik Coromant N1BU solid-carbide grade, the former can also be specified in the newly developed N1DU veined PCD grade. N1DU provides PCD across the entire cutting edge, thus offering much longer tool life. Due to PCD’s low coefficient of friction and high conductivity of heat, the tool’s cutting edges are less susceptible to built-up edge. As a general guide, Sandvik Coromant recommends the use of the solid-carbide grade when the hole count is low and handling risk is high, while the PCD grade is preferable where hole count is high and higher productivity is required.
CoroDrill 400 is recommended for drilling into solid material, as it features more flute volume for better chip evacuation. When drilling into cored material or pre-cast holes, CoroDrill 430 will perform better as it features three flutes for increased stability and holding true positon, regardless of misaligned cored holes.
Optimised features of CoroDrill 400 and CoroDrill 430 include polished flutes and precision coolant holes, with support provided for MQL. The drills are available as standard in 5, 6.8, 7, 8.5, 10.2 and 12.5 mm diameters, which correspond to M6, M8, M10, M12 and M14 thread sizes. Tailor Made options can also be specified for other applications.
In support of the drills are CoroTap 100, 200, 300 and 400; a series of taps that is also designed specifically for use in ISO N materials. CoroTap 100 is straight-flute tap for through and blind holes that features interrupted threads for less torque and increased coolant penetration.
CoroTap 200 is a spiral-point tap for through-holes, while CoroTap 300 a spiral-flute tap for blind holes. These taps are available as high helix (35°) uncoated variants for low Si content aluminium, or low helix (15°) coated or uncoated types for abrasive, high Si content materials. CoroTap 400 is a forming tap for through and blind holes that features optimised lobes and thread length to reduce torque in aluminium workpieces.