CrazyDrill Cool Titanium. Photo: Mikron Tool

Mikron Tool recently introduced its new CrazyDrill Cool Titanium ATC/PTC series of drills to ensure maximum process reliability when drilling pure titanium and its alloys, as they pose a chip-removing machining challenge. The company also says that depending on whether it is pure titanium or alloyed titanium, the chip-removing process behaviour differs, which is why it has developed drills ‘perfectly tailored’ to the respective titanium grades.

“Machining titanium is highly demanding. One of the reasons is its combination of high elasticity and high tensile strength. Moreover, high toughness means chip breaking is difficult to achieve, while low thermal conductivity means heat is not dissipated from the cutting area through the chip. Compounding this is that titanium tends to form built-up edges, which leads to higher wear and reduces process reliability during drilling — a process that is much more challenging than milling.

“The viscoelastic property of titanium causes the drill to stick, with the increased pressure on the cutting edges usually leading to uncontrolled drill breakage. Chip shape is also problematic, because titanium chips tend to compact in the head area and prevent further chips from flowing in; the high temperature load on the cutting edges is an additional complicating factor, which is why cooling lubricant must reach the machining area directly — hence our use of two cooling channels with large cross-sections that can carry copious amounts of coolant to the drill tip to both cool and flush chips through the polished flutes.”

Mikron also says that because not all titanium is alike, to machine it efficiently it is necessary to understand its every detail. “Pure titanium (grades 1-4) is characterised by high corrosion resistance, but has lower mechanical strength, while alloyed titanium (grade 5 and higher) has high strength but low ductility. Following detailed development work, Mikron Tool designed two specific geometries — one for pure titanium grades and one for titanium alloys — that perfectly control chip removal while achieving high drilling speeds, long tool life and repeatable processes.”

The new CrazyDrill Cool Titanium series is offered in the diameter range 1-6.35mm. For pure titanium, Mikron Tool developed short drills with a 3xD and 6xD capability. For titanium alloys, Mikron Tool offers drills with 6xD and 10xD in combination with a pilot drill.