The G320 twin-spindle turn-mill centre from German lathe manufacturer Index, featuring two lower tool turrets and an upper B-axis milling spindle head, is a new addition to the company’s product range.

Together with the new G300 that uses a third turret in place of the tool spindle, they complete the German manufacturer’s range of high-performance centres for turning and milling of complex, medium-size components in one hit. Sole sales and service agent for the UK, Irish, and Gulf markets is Gosport-based Kingsbury.

Capable of machining components up to 1,400mm long, the G320 joins a larger G420 model, introduced in 2018, the success of which led swiftly to the addition of an even bigger, more powerful G520 variant and a smaller version, the G220. These other sizes of machine have equivalent options that deploy an upper turret rather than a B-axis spindle.

All four model sizes share the same design, based on generously dimensioned linear guideways in the X and Z axes and a rigid, mechanically and thermally stable, mineral-cast monoblock machine bed with excellent vibration damping characteristics. The machines also offer dynamic axis movements and fast rapid traverse rates up to 50 m/mm for top machining accuracy combined with high levels of productivity.

The milling spindle of the G320, positioned above the centreline of the identical, twin-opposed main and counter spindles, has -25 to +205deg of B-axis swivel and 250mm of Y-axis movement in addition to X/Z linear travels of 620/1,400mm. Full five-axis machining at either work spindle is therefore possible in conjunction with the C axis.

The tool spindle rating is 16.6kW, 72Nm, 12,000rev/min (100% DC) or 16kW, 45Nm, 18,000rev/min (100% DC), providing plenty of power, torque and speed for completing a wide range of drilling and milling operations. It is served with cutters from a magazine with space for up to 111 tools (HSK-T63 or Capto C6).

The powerful, 4,000rev/min work spindles are rated at 44kW/525Nm (100% DC), 59kW/715Nm (40% DC), and are designed for bar diameters up to 102mm and turn-milling chuck parts to 315mm diameter. Turret steady rests are available for external turning or deep hole drilling of long, shaft-type parts up to 101mm in diameter.

The two tool turrets with ±60mm Y-axis movement arranged below the axis of workpiece rotation also help to ensure efficient machining. Each can have either 12 VDI40 stations or 15 VDI30 stations, all of which are live.

Due to the size of the working area, the large distance between the main and counter spindles, and the ability of the lower tool carriers to pass beneath the spindles, simultaneous machining is possible with the tool spindle and both of the lower turrets without risk of collision, even when all three are working at the same spindle.

The turn-mill centres may be equipped with several automation options including an integrated 2- or three-axis gantry handling arrangement. They are designed for automatically loading billets up to 20 kg, unloading finished components and removing bar remnants.

A six-axis robot cell, iXcenter, with a 165 kg load capacity and 2,660 mm reach may be positioned to the right of the lathe and used instead of or as well as a gantry loader. Further automation solutions such as conveyors or robot handling with ancillary functions can be integrated.

The Index iXpanel control is a modified version of the Siemens S 840D sl platform. It has an 18.5in touchscreen monitor and is compatible with Industry 4.0.