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ADVANCES IN MACHINING AIRFRAME AND ENGINE PARTS


09-06-2016

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Farnborough International Airshow 2016 - Press preview - Makino - Chalet C4
 
 



Staff from NCMT, the sales and service agent in the UK for Makino machine tools, will be present in the Japanese manufacturer's chalet during the show to promote four distinct areas of production in the aerospace industry.
 
One is milling of aircraft structural parts in titanium alloys using Makino's T-series of horizontal machining centres. Another is machining of aluminium aerostructures on the latest MAG and -nx series of 5-axis horizontal-spindle machines. A third highlight will be production of nickel alloy engine parts and other components using multi-axis, creep-feed VIPER grinding, combined with other machining operations. Finally, EDM drilling of holes in turbine blades will feature.
 
Titanium machining
 
Very high metal removal rate is a hallmark of Makino T-series machining centres, which are typically able to hog up to 500 cm3 of Ti-6Al-4V per minute. Despite having such impressive roughing performance, the machines are also capable of 5-axis simultaneous finishing to very high precision.
 
A significant technological advance is the use of three rotary CNC axes, a ±110-degree A-axis and a 360-degree C-axis on the spindle head, plus 360 degrees of continuous movement of the B-axis table. The user is able to choose A/C mode and position B for machining airframe parts, for example, or can select A/B for efficiently machining engine casings and other circular components. In either case, the sixth CNC axis can be repeatedly repositioned during a machining cycle.
 


Aluminium machining
 
Makino offers its MAG series of 5-axis, horizontal machining centres for producing large aircraft structural components but at the smaller end of the scale, the a51nx, a61nx and a81nx models offer raised productivity, accuracy and reliability.
 
The 40-taper machines feature improved casting designs as well as enhancements to the spindle and guideways. They impart rigidity, precision, lower vibration and longer tool life normally associated with 50-taper HMCs, while maintaining high speed machining capability. An HSK-A63 interface is optional.
 
The latest a81nx features 900 mm by 900 mm by 1,020 mm axis travels. The magazine, which includes a tool loading station, can accommodate up to 299 cutters, chip to chip time being 3.7 seconds for a 12 kg tool. Two spindle designs provide high productivity; 10,000 rpm is standard, while the optional 37 kW / 8,000 rpm, high-torque spindle boosts continuous power levels for tough cutting applications.
 
VIPER grinding
 
For producing aero engine parts from nickel alloys and for milling components in other difficult-to-machine metals, VIPER (very impressive performance extreme removal) creep-feed grinding is capable of stock removal rates up to eight times those achievable when conventionally grinding nickel alloys using a plated CBN wheel.
 
Broaching, milling and turning operations can also be eliminated using the VIPER superabrasive process. In all cases, consumable costs are reduced dramatically. Makino NCMT Grinding Division offers this technology across continental Europe and Scandinavia in addition to the UK and Ireland.
 
Noteworthy is the design of the programmable coolant nozzles, which are repositioned during grinding by two rotary NC axes anywhere through 360 degrees around the periphery of the grinding wheel. Nozzle movement is fast and responsive when changing orientation to ensure that coolant continues to be accurately directed towards the point of cutting at all times.
 
The most recent development from Makino is the 7-axis i-Grinder G7, which like other VIPER machines is based on a machining centre platform. It allows grinding wheels and other metalcutting tools to be exchanged automatically between the tool magazine and the spindle, allowing a variety of machining operations to be carried out in the same cycle.

The smaller Makino i-Grinder G5 accepts parts nominally up to 300 mm diameter, 
but with increasing aircraft engine size, some larger vanes were falling outside the machine's working envelope. The 730 mm by 650 mm by 730 mm capacity of the G7 addresses the problem. Increased space in the machining area also allows room to house two roll stacks to dress the grinding wheels, allowing flexibility to produce a greater variety of components without having to change the rolls.

EDM drilling
 
Makino’s EDBV (electrical discharge blades and vanes) series of electric discharge machining (EDM) centres for hole drilling have been specifically designed for the production of cooling holes and diffuser shapes in aerospace blades and vane segments.
 
The EDBV3 provides aerospace manufacturers with the speed, flexibility and reliability to effectively produce a wide range of shapes and sizes in a single set-up, significantly reducing the variety of tools required and overall cycle times. More recently, the EDBV8 has been introduced to deliver top performance and optimal speed when machining larger, heavier workpieces.

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