The inverted spindle travelling column design of vertical turning lathes provides a self-loading cycle and two machines can be installed side by side to handshake and reposition the part.

Creating a very simple solution to unmanned turn/mill cycles, the inverted spindle travelling column design of vertical turning lathes from Hyundai-Kia in the SKT 21 VM provides a self-loading cycle whereby the machine spindle picks up and deposits components from an integrated pallet-based stocker. Such is the configuration of the system that two machines can be installed side by side to handshake and reposition the part to provide first and second operation turn/mill cycles with the integrated loading stocker and unload stocker respectively sited at each end of the cell. The SKT 21 VM is one of the latest high specification and quality machine tool solutions now available through C Dugard of Hove, Sussex, under the banner of Hyundai-Kia Machine, Korea's largest by some significant margin machine tool company.

The machine is the most recent from the machine tool division of the $2.8 billion Hyundai-Kia Automotive Group that is creating high productivity solutions from the production engineering requirements of its parent and its subcontract part suppliers from around the world.

Here, the self-loading cell-based turn/mill technology was high on the development agenda.

Having a maximum turning diameter of 250mm by 150mm long, this 8in chuck size machine has a 12 station, servo-driven turret with each position able to accept live tools powered by a 3.7kW, 4,000 rev/min motor.

Live tool capacity is 20mm and M16 for threading tasks.

Turret indexing time is 0.3s via a three-piece coupling unit having a hydraulic clamping force of some 43kN (4.3 tonf) to provide a high rigidity cutting unit.

The built-in spindle has an 11kW motor giving 30 to 5,000 rev/min with a 0.001 deg C-axis controlled from the Fanuc Oi-T unit.

A high accuracy specification of +3.5 microns and roundness capability within +0.5 microns is achieved from the combination of the quality build specification that includes a thermally symmetrical headstock, square box-type ways set on a cast iron bed able to absorb vibration and maintain control over thermal distortion.

With rapid traverse rates of 30m/min, the travelling column spindle arrangement is able to deposit the completed part and pick-up the next component from the stocker unit in order to maintain high levels of overall machine utilisation.

There are two types of stocker available with eight or 12 pallet options.

Each pallet has three adjustable guide posts for internal or external part support and a rotating common cam mechanism that automatically centres the component ready for the inverted machine spindle to perform a clean pick-up.

With the inverted spindle configuration, swarf control is excellent using high slant angle bed covers that funnel the chips directly into a central conveyor.

This enables swarf to quickly exit the working area without influencing the thermal characteristics of the machine.