WNT drill offers longer tool life, higher productivity

Ideal for medium to large batch sizes of steel or cast iron components and available from 3.00 mm through to 20.00 mm in 0.1 mm increments as standard, WTX Speed is delivering reductions in drilling cycle times of up to 60 per cent, thanks to its ability to run at speeds up to 240 m/min - double that of conventional solid carbide drills - and feedrates typically 20 per cent higher, with no perceivable loss in tool life. Those companies not willing, or able to capitalise on the higher cutting data will benefit from tool life increases of between 50 and 60 per cent when running at 'conventional' speeds and feeds. In a typical application, drilling 42CrMo4 material with an 8.5 mm diameter drill producing 40 mm deep holes, a WTX Speed drill ran at 200 m/min at a feed of 0.28 mm/rev and produce 1,900 holes before it required changing. Its nearest competitor achieved just 1,150 holes. These improvements are achieved through a radical redesign of the drill point, the use of a brand new sub-micron carbide substrate with grain size between 0.5 and 0.8 micron, and the latest Ti800 tool coating technology. The drill point features an asymmetric design, which reduces vibration and improves runout; it also features two circular lands and a secondary cutting edge that helps to reduce friction/heat and improve tool life. To help deal with the increased volume of swarf created at the higher cutting data, the drill flutes have also been redesigned. For a length of 1.5 x diameter, the flutes are parallel and then open up to make swarf evacuation easier, a situation helped by the increase in size of the through-tool coolant delivery holes, something only possible due to the core strength of the new carbide grade. The final piece in the WTX Speed jigsaw is the use of the Ti800 coating, which has a micro-hardness of [HV0.05]:3,700 max, and the ability to operate at temperatures up to 1,100 °C. Part of a new generation of titanium aluminium coating materials, TI800 is a nano composite supernitride coating structure with a high aluminium content. The use of supernitride coatings prevents built up edge and adhesion of swarf to the cutting edge and flutes thanks to their ability to resist heat, oxidisation and abrasion. WNT has also looked at the application process of the coating and has created a system that sees a greater thickness of coating is applied to the drill point where it is most needed.