Index has launched a second eight-spindle CNC automatic lathe — one that is capable of turn-milling components from bar up to 40mm in diameter.

The new Index MS40-8 is available in the UK and Ireland through Gosport-based Geo Kingsbury Machine Tools Ltd (www.geokingsbury.com); it follows the manufacturer’s first eight-spindle multi (with a bar capacity of 24mm), which was introduced in 2011.

CNC multi-spindle automatics normally have six spindles. The two additional stations facilitate the complete manufacture of components of even higher complexity, in short cycle times.

Alternatively, more-simple parts can be produced in half the time, using the machine as a double four-spindle auto (indexing the drum by 90deg each time instead of 45deg to produce two parts per cycle).

The MS40-8, which is also capable of chucking cast, forged or extruded parts up to 80mm in diameter, is aimed at high-volume production in the automotive, connector and aerospace industries. However, smaller batches can be produced almost as efficiently and economically as larger runs, due to the speed of set-up inherent with CNC rather than cam technology.

In addition to turning, cycles may include drilling, elliptical deburring of cross holes, milling, hobbing, tooth milling, deep-hole drilling and slotting.

Up to 18 CNC cross slides (X and Z) can be specified on the MS40-8, along with additional Y axes as an option. The low-mass slides with hydrostatic support are wear-free and avoid stick-slip.

A low moment of inertia allows rapid acceleration, while high damping characteristics prevent the transfer of machining vibrations to the adjacent slide via the headstock, says the company.

Each of the eight spindles in the drum is fluid-cooled to minimise thermal growth. They are rated at 24kW 7,000rev/min (57Nm of torque) and feature independent steplessly variable speed control.

A C axis is available for all spindle positions, facilitating the complete machining of complex workpieces in conjunction with live tools on the compound slides.

Furthermore, two pivoting back-working spindles can perform simultaneous operations on the rear of components in conjunction with seven dedicated tools, four of which may be live.

The spindles are locked into position by three-part Hirth couplings, assuring high levels of stiffness so that heavy cutting does not compromise precision.

Energy recovery by means of regenerative drives is included, while units that consume large amounts of energy are put into stand-by after a user-defined time.