Horizontal machining centre for mass production

A new, high-speed, horizontal machining centre built by Okuma, Japan, has been introduced to the UK by NCMT for efficient prismatic metalcutting in large volume production.

A new, high-speed, horizontal machining centre built by Okuma, Japan, has been introduced to the UK by NCMT for efficient prismatic metalcutting in large volume production environments.

Weighing eight tonnes and occupying a floor area of a little over 1.5 metres by 3.5 metres, the MT-40H is a robust, compact machine which is offered with 3-axis gantry-type component load / unload equipment able to serve one machining centre or several interlinked machines.

The moving column, which provides Z-axis traverse of 420 mm, travels on a saddle with 520 mm of X-axis movement.

Vertical Y-axis travel of the spindle head is 460 mm.

Consequently the workpiece (which can weigh up to 400 kg) and the table remain static during 3-axis machining, allowing consistently high precision results to be achieved.

Accuracy is further promoted by the use of hollow ballscrews which are continuously cooled during operation; spindle thermal deviation correction by monitoring the temperature of the bearings, motor and stator and adjusting the through-spindle coolant flow accordingly; and comprehensive chip (and hence heat) removal using a rapid flushing system and a drum filter which can trap particles down to 20 microns.

What defines this machine above all else, however, is its speed of operation, said to allow production rates up to 50 per cent higher than the equivalent previous model in the Okuma range by minimising non-cutting times.

Rapid traverse of 60 m/min in all axes and attainment of that speed in a blisteringly fast time of 0.1 second is achieved using high lead ballscrews and high speed linear guideways.

Acc/dec of 1g means that the cutter, from a standing start anywhere in the working area, can be 400 mm away in all three orthogonal directions within half a second.

Spindle start-up time is also fast, top speed of 7,000 rpm being achieved in 0.7 second.

A 15,000 rpm spindle is optional.

Exchange of the 40 taper tools from the 12-station (optionally 24-station) magazine using the new V-shaped automatic tool change arm takes just 1.3 seconds for tools weighing the maximum of 8 kg.

Control is from the Okuma OSP-U100M CNC which provides such features as absolute position feedback to avoid a zero recovery start after an unscheduled stop in production; and in-built intranet/extranet features for remote control and monitoring.

High speed NURBS capability and control over the optional NC rotary table are available on request, as are helical milling and rigid tapping.

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