CNC multi-spindle automatic lathes have been regarded by many machine shops as too expensive.
Now, Index in Germany said that the cost of such machines is constantly reducing. It is now possible to buy a six-spindle CNC automatic (multi) for around twice the cost of a high-end sliding-head lathe, said Richard Kingsbury, managing director of the UK agent for Index turning machines, Geo Kingsbury Machine Tools.
The machine in question is the Index MS22C CNC six-spindle automatic intoroduced at EMO 2007 for milling and turning parts up to 22mm diameter.
While it is true that CNC multi-spindle automatics are not cheap machines, the price in real terms has been coming down steadily over the years.
The MS22C brings the technology within reach of a much wider section of manufacturing industry.
Kingsbury said: ‘The CNC multi-spindle range is proving so popular that Index will increase production in 2008 to 200 units across all sizes of multi.
Of these, 80 will be in the 22mm category.
Four fifths of them are destined for Germany, France, Switzerland and Italy’.
Kingsbury commented that British manufacturers have been falling behind in adopting the technology, but that he has high hopes for an increased level of order conversions in 2008, due to the introduction of the competitively priced MS22C.
OEMs and subcontractors alike are beginning to see the productivity advantages, having noted the big advances in capability of the machines.
Kingsbury said that he is particularly encouraged by the fact that, once a customer has been ‘won over’, not one has stopped at a single multi; they have all gone on to buy a second, third, fourth and even a fifth machine.
He continued, ‘A few years ago, people cottoned to the fact that modern CNC sliding-headstock lathes could make a lot of money.
Many firms invested, mostly in multiple machines and some subcontractors have as many as 25 or more.
But where is the competitive edge now that so many firms use them?
I suggest that if component length-to-diameter is 4:1 or less, the next big thing in British turned parts manufacture will be the CNC multi, with its extensive prismatic machining and endworking capabilities, coupled with the flexibility to run batch sizes of just a few thousand’.
Kingsbury added that competitive pricing has placed these machines in the ‘mainstream’ of manufacturing, and programming and operation have been ‘demystified’ to the point where operation is almost as simple as running a single-spindle CNC lathe.
* About the Index MS22C multi-spindle automatic - the six-spindle mill-turning centre has been added to the lower end of the Index range, which until now comprised machines with maximum bar capacities of 32, 42 and 52mm.
According to configuration, the MS22C can have up to 62 CNC axes, including 12 compound slides with X and Z travels of 62 and 85mm.
Each spindle is configured with a full C-axis and a number of Y-axis slides can be added.
Simultaneous back-working is achieved using one or two scara robot arms carrying synchronous pick-up spindle(s) that present the parted-off components to six separate tools, four of which can be driven.
As the MS22C’s tool carriers/slides are arranged in a V shape, two CNC slides can work on one spindle simultaneously.
This is in contrast to the configuration of multi’s from other manufacturers.
Each of the 12 slides can perform internal or external turning, or boring, or driven tool work.
Workshops are therefore not locked in to running one kind of tool in one position, because there is no set order as to where to run which tool.
Only the toolholder determines the type of machining.
This flexibility of tool layout plays a key role in optimising machining times, according to Index.
Although the machine can be extended to the full 62 axes, this is rare in practice.
The standard configuration would be with a single NC system capable of controlling 31 programmable axes, more than adequate for the vast majority of small turned parts, said Kingsbury.
It is a specification that offers all the benefits of phenomenal production rates without the restrictions in flexibility that are normally associated with multis.
* feed rates and cutting speeds optimised at each spindle - in common with other Index CNC multis, the MS22C 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 production of components in materials such as high temperature alloys that previously could not easily be machined on a multi.
Control is by the INDEX C200-4D, a derivative of the Siemens 840D CNC, which is easy to program on the shop floor and automatically performs collision checking including 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.