Two in one go - vertical turning centers combine either end-machining and finish-turning operations, or - on its two-spindle variant - pre- and finish-machining of both shaft ends.

Emag showed its VTC 250 DUO Vertical Turning Center at METAV Dusseldorf, Germany. The machine meets further demands for the consistent application of combined process sequences. Its users will profit from minimal throughput times, greater integrity of the process capability and higher precision.

The VTC 250 DUO will machine shaft-type workpieces of between 70 and 630mm (optionally up to 1000mm) length, up to 140mm in diameter and 20kg in weight, starting with the forging blank or billet and finishing up with a complete-machined component.

For this purpose the machines are equipped with three turrets, a main spindle and a separate clamping station.

Once the first turret has collected the raw part from the loading point and conveyed it to the clamping station, it proceeds to machine both ends with its two sets (one each for front and rear) of up to four life tools (power rating 38kW, speeds of max.

1400 rev/min).

On completion of the end machining operations turret No-2 conveys the component to the second machining station, where it is clamped in the main spindle chuck and - supported by a tailstock (and, optionally, by CNC steadies) - finish-machined in 4 axes by up to 11 tools each in the second and third turrets, where power ratings of 29kW, torques of up to 200Nm and main spindle speeds of up to 5000 rev/min together with direct-drive feedrates of up to 40 m/min produce short cycle times.

The VTC 250 DUO can also be equipped with a high-powered main spindle of 38kW and 300Nm torque rating as an option.

A further option would be to have the VTC 250 DUO equipped with two main spindles.

This variant is suitable for pre- and finish-machining in a single process sequence.

It also allows for the finish-machining of both shaft ends, whereby the workpiece can be turned around during transfer from one to the other spindle.

Compared to the sequential machining of shafts on a number of machines, this extensive application of combined process sequences on a single lathe considerably shortens throughput times.

Complete-machining in a single production sequence also noticeably reduces component manufacturing costs.

Combined with its high degree of flexibility in handling different workpiece lengths the VTC 250 DUO offers great advantages also in the manufacture of medium-size batches where the workpiece type changes frequently, i e, where component families contain a large number of variants.

Following the principle to always offer its users the best manufacturing solutions, Emag is able to supply other equipment to complement the machining area of the VTC 250 DUO, such as belt grinders for super-finishing operations, deburring spindles, or internal and external cylindrical grinding spindles.

In all cases Emag uses standard components and interfaces, thus offering a way to quickly construct a cost-effective special purpose machine from standard production components.

It ensures that Emag complies with the increasing demands for greater flexibility in the provision of suitable manufacturing solutions.

The extensive application of combined process sequences provides considerable advantages for manufacturers.

A single process sequence on a single machine transforms raw parts into ready-to-install components.

This raises product quality by reducing the number of set-ups.

It also minimises procurement costs and floor space requirements.

In fact, the requirement reduces from several machines - for end working, pre- and finish-turning, turning and milling, deburring of the tooth profile - to just one machine: the VTC 250 DUO.

Cutting speeds and feed rates surpass those of other turning centers and thus reduce cycle times.

The VTC Turning Center can also be used to hard turn.

The sophisticated Emag design makes sure of all this.

Its cornerstone is a sturdy machine base in Mineralit polymer granite with the advantage that its vibration dampening properties are superior to those of grey cast iron.

This allows the machine to work at considerable higher cutting speeds and feed rates and for tools to have a much greater life expectancy.

A fluid-cooling system for main spindle, turrets, electrical cabinet and machine base makes for greater precision.

A twin-circuit heat exchanger maintains the machine temperature within tight limits of the ambient temperature.

Today's demands for flexibility in all in-house operational procedures are met by the construction and assembly of the machine components into a 'hook-up-and-install'-type machine.

In a further development, Emag offers the VTC 315 Vertical Turning Center for the machining of workpieces of 60kg in weight, up to 630mm long and up to 250mm in diameter.

Its main spindle speed is 4000 rev/min.

The 50kW power rating and a torque rate of max.

800Nm make sure that even large components can be machined economically and that manufacturers of primarily heavy shaft-type components too can profit from the extensive application of combined process sequences offered by the VTC from Emag.