Several important performance targets were set before release – the most important being tool life and reliability. To achieve these objectives, a number of features were built into the geometry, substrate and coating of the DSAS drills.
A tried and trusted straight type cutting edge is utilised because this provides an even cutting load spread as well the required toughness needed for machining HRSA materials. This geometry, together with a dedicated edge honing provides the drill with high resistance to edge chipping, breaking chips efficiently and allowing easy ejection that prevents jamming of the flutes.
Additionally, the sharpness of the edge geometry was found to produce a lower thrust force than conventional drills when machining titanium.
The margin has been made thinner than used on conventional drills which provides the benefit of reduced cutting loads and much reduced level of work hardening of the hole wall surface. When drilling Inconel 718 the hole roundness and the surface roughness of the hole wall were found to be superior when compared to conventional products.
An essential feature of drills for difficult to cut materials is the efficient supply of coolant delivered to the cutting edge. The direct through coolant hole feature provided on all DSAS drills means that essential cooling and lubricity at the cutting edge can be provided. Furthermore, a sufficient supply of coolant also greatly aids chip evacuation
To complement all the advanced geometrical features, a brand new carbide grade, DP9020 was developed to optimise the overall performance and reliability of the DSAS series. A substrate with a balance of hardness and toughness was developed and a suitable PVD coating added to provide wear resistance to the substrate’s natural fracture resistance.
Available in 64 different sizes ranging from 3mm to 12mm, the DSAS series brings not just performance but the overall drilling package of hole accuracy, reduced work hardened layer, surface finish and repeatability as well as all-important, process reliability.
Mitsubishi Materials www.mitsubishicarbide.com