Top tools for titanium

At the recent EMO exhibition in Hannover, Mikron Tool presented the new CrazyDrill Cool Titanium ATC/PTC series, which, according to the Swiss tooling specialist, ensures maximum process reliability when drilling pure titanium and titanium alloys.

Machining titanium is challenging – and pure titanium differs from its alloyed variants in terms of chip removal. For these challenges, Mikron Tool has developed drills tailored to the respective titanium grades enabling manufacturers to machine titanium safely, with high cutting performance results, longer tool life and excellent hole quality.

One of the main reasons titanium is difficult to machine is because of its high elasticity and tensile strength. Because of its high toughness, chip breaking is difficult to control – due to its low thermal conductivity and the fact that heat is not dissipated from the cutting area through the chip. In addition, titanium tends to form built-up edges; it all leads to higher wear and reduces process reliability during drilling.

And drilling titanium is much more challenging than milling. The viscoelastic property of titanium causes the drill to stick, and the pressure on the cutting edges increases, usually leading to uncontrolled drill breakage.

Material sticking on cutting edges and guide chamfers increases cutting forces which can result in the cutting edges breaking out. Moreover, the chip shape is also problematic. This is because the 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 complication.

To reduce heat in the cutting area, the cooling lubricant must reach the machining area directly. The two large cooling channels in the CrazyDrill Cool Titanium ATC/PTC series carry huge amounts of coolant to the drill tip and guarantee constant cooling including lubrication of the cutting edges. At the same time, the substantial coolant jet flushes the chips through the polished flutes and prevents chip jams.

The patented special shape of Mikron Tool's cooling channels enables a 4 x higher volume of coolant to be propelled through the tool at the same pressure resulting in excellent thermal dissipation and chip removal.

To process titanium efficiently, it is vitally important to know its various compositions. Mikron Tool has examined various test materials and discovered that the different grades of titanium are extremely different from each other. Pure titanium (grades 1-4) is characterised by high corrosion resistance but has lower mechanical strength. Alloyed titanium (grade 5 and higher) has high strength but low ductility.

Getting to grips with these differences in terms of machining technology is key. Through extensive R&D work, Mikron Tool engineers found the ideal solution: two specific geometries – one for pure titanium grades and the other for titanium alloys. Controlled chip removal, high drilling speeds, long tool life and process repeatability with optimum drilling quality is therefore guaranteed.

The new CrazyDrill Cool Titanium series is offered in the diameter range of 0.039" – 1/4" (1 - 6.35 mm). For pure titanium, Mikron Tool developed short drills with 3 x D and drills with 6 x D. For titanium alloys, Mikron relies on drills with 6 x D and 10 x D in combination with a pilot drill.

For the cost-effective production of titanium components, tools are required which are specially adapted to the material properties of the various titanium grades.

Titanium is expensive, which is why high process reliability and calculable tool life are so important. Mikron Tool claims its new high-performance drills for titanium have up to three times longer tool life and work with twice the feed than its competitors. Also, drilling with the ATC-version is completed in one shot, without multiple machining steps.

In the UK, Mikron Tool is represented by Baldock, Hertfordshire-based Floyd Automatic Tooling.

Floyd Automatic Tooling
www.floydautomatic.co.uk

Mikron Tool
www.mikrontool.com