TPT July 2011

C utting , S awing & S aw B ladeS

Titanium troubles solved by Prototyp tooling TESTS with a Walter Prototyp carbide milling cutter have shown Airbus that it can transform its titanium machining capabilities, doubling cutting volumes during roughing operations on one workpiece. Ti40 solid carbide end mill. This tough and relatively vibration-immune carbide has proved its worth in the Airbus project.

Walter’s G77 insert geometry (with large rake angle of 20deg) has been optimised for titanium alloys and is now available for shoulder mills and porcupine cutters (type ADGT) and round insert cutters (RO.X). Walter GB Limited – UK Fax: +44 1527 839499 Email: service.gb@walter-tools.com Website: www.walter-tools.com

Further Walter trials – in this instance with Ti5553 (Ti-5Al-5V-5Mo-3Cr), a near-beta alloy with higher temperature resistance than Ti6Al4V and a Brinell hardness of 430 – have also proved successful when using the Ti40 at reduced cutting speeds and feeds. Walter’s on-going developments in titanium machining also include larger diameter tools that necessitate the use of PVD Tiger.tec inserts – WSM35 with high wear resistance for good machining conditions and WSP45 with increased toughness for difficult conditions.

Applied to the Ti6Al4V alloy, a 25mm diameter Prototyp Ti40 solid carbide end mill removed 160-200cm 3 /min of material at feed rates of 50-60m/min. This compares with 80cm 3 /min at 25m/min using a 32mm HSS tool – cutting data that has characterised the Airbus workpiece since the mid-1990s. Machining of Ti6Al4V is inherently problematic, according to Walter GB. The material, widely used for aerospace applications, has extremely poor thermal conductivity (Ti6Al4V is 7.56W/mK while Ck45 steel is 51.9W/mK), a low elastic modulus (110kN/mm 2 compared to Ck45’s 210kN/mm 2 ), and a distinct tendency to ‘gum’, with the machining heat being largely dissipated by the tool’s cutting edge rather than by the swarf, as is the case with steel. However, Walter’s development of titanium-compatible carbide substrates has resulted, for example, in the Prototyp OLIMPIA 80 has designed and built a new double blade flying cut-off for in-line cutting of large pipes, in round, square and rectangular shapes, at production speeds up to 80-85m/min. The particular features of the equipment make it mainly suitable for high thickness tubes. Olimpia 80 offers different models covering a complete range from 3" to 16" tube OD. The innovative system with vertical parallel movement of blades allows the reduction of the cutting cycle time and an easier set up of the blades. The cutting speed has an increase of 30-40% compared to traditional cut-off, and the reduced contact time of the blade into the cut tube, compared to conventional cutting systems, allows a reduction of the consumption of the blade circumference. The system uses special gear boxes, without play, specifically designed and ensuring higher blade resistance and longer life. The double vertical blade cut off can be used with HSS and TCT blades. The equipment is completely computerised, and the set up of the cutting positions is performed automatically. In the

The Walter Prototyp T140 solid carbide end mill doubled cutting volumes on titanium at Airbus

Flying cutting machine with double vertical blade

case of production of section tubes, thanks to a universal tube blocking system, vice change is not necessary.

The new double blade flying cut-off

Olimpia 80 Srl – Italy Fax: +39 0523 864584 Email: olimpia@olimpia80.com Website: www.olimpia80.com

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J uly 2011

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