CNC miller/borer vertically turns as well

Described as a 'cross between a heavy duty vertical turning and boring facility and a 5-axis machining centre' a bed-type machine has a 30kW turning table.

NCMT in the UK said that manufacturers are increasingly demanding the capability to machine components in a single set-up to achieve short lead times, improve accuracy and reduce work-in-progress (production inventory).

Okuma has introduced the VTM-80YB, which is intended for single set-up machining of parts weighing up to 1.5 tonnes.

NCMT described the 23 tonne Okuma machine as a 'cross between a heavy duty vertical turning and boring facility and a 5-axis machining centre' and the machine can simultaneously interpolate up to four CNC axes.

Structurally it is configured as a bed-type machining centre, but instead of a conventional table it has a 30kW turning spindle/table driven through a two-speed gearbox.

The drive provides steplessly variable speeds in the range 4 to 270 rev/min (low range) and 8 to 800 rev/min (high range).

In addition it provides 360,000-increment C-axis positioning.

Two large-cross-section, X-axis slideways carry a substantial column with vertical Z-axis slides.

These in turn locate a saddle with Y-axis cross slides to support the 18.5kW / 4,000 rev/min motor-spindle (B-axis).

By locking the motor spindle using a Curvic coupling it becomes possible to use it for turning operations without risk of damage to the bearings.

The B-axis can position the spindle between vertical and horizontal machining positions in 5-deg increments.

The positioning facility available on the B-axis allows standard tooling to be used in situations where specials might otherwise have to be considered.

In addition, it is possible to improve milling efficiency when using ball nose cutters by using the tool at an angle to avoid zero surface speed cutting at the tip.

Similarly, angled holes can be produced without the need for special fixtures using a three-dimensional co-ordinate conversion facility within the control software.

In standard form, up to 36 BT50 Big Plus or CAT50 taper tools are stored in a free-standing tool magazine for exchange into the vertical spindle position.

Use of a common taper standard for milling and turning provides the opportunity to use certain tools for both types of operation, for example, allowing the machine to drill horizontally as well as vertically.

Tool magazines are available for up to 120 tools and maximum tool weight is 30kg.

The machine is capable of turning components up to 800mm diameter and 1135mm long.

Axis travels are 1120mm in X, 1135mm in Z and +/-355mm in Y.

Rapid traverse rate is 24m/min in X and Y, 20m/min in Z and 20 rev/min on the C-axis.

Control is by a Fanuc 18iTB CNC system using software developed by Okuma.

It provides 4-axis interpolative control plus positional control of the B-axis.

Options include an automatic pallet change system for up to eight pallets, allowing the machine to be configured as a semi-automated, stand-alone machining cell.

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