A six-spindle mill/turn bar automatic lathe can have up to 62 CNC axes, including 12 compound slides with X, Y and Z travels of 62, 24 and 85mm, a C-axis and simultaneous back-working.

A six-spindle mill-turning centre, designated MS22C, has been added to the German-built Index line of multi-spindle bar automatics, available in the UK through Geo Kingsbury Machine Tools. The new model, capable of accepting bar up to 22mm diameter, fills a gap in the range that until now comprised machines with maximum bar capacities of 18, 32, 42 and 52mm. According to configuration, the MS22C can have up to 62 CNC axes, including 12 compound slides with X, Y and Z travels of 62, 24 and 85mm and a C-axis.

Simultaneous back-working is achieved using one or two synchronous pick-up spindles that present the parted-off components to six separate tools, four of which can be driven.

For manufacturers of less complex parts that do not require extensive reverse end-working or off-centre cross machining, a lower cost model is available, called MS22C Lean.

Its compound slides omit the Y-axis, there is only one synchro spindle and three fixed tools for back-working, and the single- instead of twin-NC control needs to manage the motions of only 31 axes.

Machining possibilities are nevertheless still extensive, offering a modern alternative to high-end, cam-controlled multi's in terms of speed, but offering greater versatility and much faster changeover times.

In common with the manufacturer's other CNC multi's, the new machine has the ability to optimise feed rates and cutting speeds at each 14kW/10,000 rev/min spindle, avoiding compromised machining conditions and so maximising productivity as well as tool life.

The MS22C is therefore ideal for economical, large and small batch production of components in materials such as high temperature alloys that previously could not easily be machined on a multi-spindle bar auto.

Control is by the Index C200-4D, a derivative of the Siemens 840D which is easy to program on the shop floor and automatically performs collision checking for the pick-up spindle(s).

Comprehensive diagnostics for the machine and control are included, and it is possible to specify tool monitoring and a teleservice connection to an Index engineer for troubleshooting.

The machine may alternatively be programmed remotely on a PC running System 200 software, which accepts CAD input and has a DNC interface.

Another innovation from Index is its range of virtual machines, each of which mirrors on a computer screen the operation of different mill-turning centres including, most recently, the MS22C Lean.

The complete set-up process can be performed on a PC exactly as with a real multi, and it is even possible to carry out a continuous run to optimise the program.

Consequently, a minimum amount of expensive machine time is wasted when changing over to produce a new component, which is ever more important with falling batch sizes.

Any potential collision situations are accurately predicted and corrected before the first-off component is produced, eliminating the chance of damage to the machine.