CNC machining aerospace engine parts, structurals

NCMT will feature the milling of aircraft structural parts and grinding of engine components using the VIPER process at the UK's Farnborough International Airshow.

NCMT will feature on Makino machine tools the CNC milling of aircraft structural parts and CNC grinding of engine components using the Rolls-Royce VIPER process at the UK's Farnborough International Airshow.

* Milling - NCMT will display an Airbus A380 wing rib measuring 3m by 1.75m, milled from solid aluminium to close tolerance at Filton, UK, on Makino MAG-Series horizontal, five-axis machining centres.

On display also will be a rib for the A320.

The workpieces are representative of the wide range of aluminium structurals for aircraft being machined worldwide on high-speed Makino machines, said NCMT.

The machines can produce large, complex components to very high accuracy in a single set-up, eliminating two or more sub-assemblies and so dramatically reducing manufacturing lead-time and cost.

On the topic of milling titanium, NCMT told manufacturingtalk that there are a number of developments on the way from Makino.

Innovations will include new machines and spindles, including a high torque (1,050Nm) gearless spindle.

* VIPER creep feed grinding - for producing engine parts, VIPER creep-feed grinding gives stock removal rates of 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, said NCMT.

Now the Makino i-Grinder G5 has been designed specifically to exploit the technology to the full.

Until now, the platform used was a standard horizontal machining centre (HMC).

The HMC had been extensively modified with very high-pressure coolant delivery to the vitrified aluminium oxide wheel via programmable nozzles and through the high-speed spindle.

The 5-axis Makino i-Grinder G5 is available through Makino-NCMT Grinding Division, a company formed to market the turnkey manufacturing systems across Europe and Scandinavia.

Recent sales successes have been recorded in Italy and Germany for the manufacture of compressor and turbine blades, and BLISKs, while Makino has sold a number of machines to aero engine manufacturers in Japan.

Overall, the i-Grinder G5 is 10% quicker at machining nickel alloy components than the modified Makino A55 machining centre that it supersedes.

Metal removal rate is of the order of 80cm3/min and the machine accepts parts nominally up to 300mm in diameter.

The enhancement in grinding efficiency comes from a number of factors, including an increase in linear rapid traverse rate from 40 to 48m/min.

Faster rotary workhead speed, which has more than doubled to 100 rev/min, is especially beneficial when grinding smaller components, said NCMT.

* programmable nozzles system improved - probably the most critical improvement is in the design of the programmable coolant nozzles.

They are more versatile on the i-Grinder G5, as they may be positioned by two rotary NC axes anywhere through 360 deg around the periphery of the grinding wheel, rather than through just 180 deg with the A55.

To achieve this greater degree of freedom, power and coolant supplies are built-in, rather than being delivered through an umbilical cord.

Nozzle positioning speed is faster and therefore more responsive when changing position to direct coolant accurately towards the point of cutting.

A big advantage of VIPER grinding on a horizontal machining centre is that in addition to abrasive wheels, other live and static tools such as milling cutters, drills, broaches or turning tools may be exchanged automatically between the tool magazine and the spindle, allowing additional machining operations to be carried out in the same cycle.

Related technologies that have been developed by Makino-NCMT include EasyGrind and EasyGear programming software, flexible fixturing, and manual or in-cycle part measurement, verification and truing.

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