More Multispindle Autos

If someone had told me that world demand for multi-spindle automatics was increasing, I would have liked to know where the figures came from. Well, the "Preliminary Offering Circular" issued by Tornos of Switzerland to potential new shareholders, spoke of increasing demand for multis.

The company believed that in 2000, total sales of multi-spindle lathes worldwide amounted to $441 million, compared with $424 million in 1999 and $401 million in 1998. Tornos held a 19 percent market share in 2000 and listed the German companies Schutte and the Gildemeister Group as its main multi-spindle competitors.

It was not so long ago—say 10 to 15 years—that some companies in Europe, such as the bearing, automotive, pipe connector and fastener producers, could not junk their multi-spindle autos fast enough.

Very quickly, though, those companies found that single-spindle CNC automatics could not match the volume production of multis. The economics did not work out right when the practice of holding buffer stocks in conjunction with multi-spindle high volume operation was replaced by nil stocks and very overworked CNC single spindle automatics.

The CNC single spindle invasion of traditional multi-spindle markets spurred the likes of the then Tornos Bechler, along with Schutte and Gildemeister, to do something about the shift-long (or more) setup times necessary to do a job changeover on multis.

Another "spur" in the side of the multi-spindle lathe builder was the growing shortage of skilled multi-spindle setters.

Initially, pre-set tooling considerably reduced setup time on multi-spindles. Schutte, for example, was very hot on preaching that. Then CNC crept in, initially to replace form-turning slides and achieve more setup time savings.

I think it was Tornos Bechler that introduced the first all-CNC multi-spindle machines in the mid-1980s—at a cost. Even so, some industries—already looking for something more productive than a single-spindle auto, but without the 8-10 hour changeover time of a cam-operated multi—thought it was a good deal.

Since then, the capital cost for a CNC multi has dropped. Also, the skill requirement of a setter required to program such machines has diminished. Some new concepts have been introduced, too.

Tornos is no longer married to "we don't build machines over 20 mm (3/4-inch) bar." In 1998, the company introduced its MultiDECO 26/6 (26 mm/ 1 1/16 inch) and larger machines. Tornos also said that the faster setup times and easier programming, coupled with lower volume production campaigns, allow its multis to expand outward from the traditional high volume automotive and bearing industries, into, for example, the connector industry. Examples include valve, elbow and reducer high precision plumbing style fittings used in natural gas lines and hydraulic lines.

Schutte, as we have already seen in Production Machining pages, has introduced twin pick-off spindles for simultaneous back-end machining of parts on its a 36 PC eight-spindle CNC 36 mm bar (1 1/2 inch) machine. Note, too, that the buyer can choose between the more common single 28 kW drive to all spindles or have an independent 12 kW drive on each spindle. The latter allows you, for example, to introduce constant surface speed profiling. All tool and independent spindle drives offer full electronic interconnection; in other words, all tool and spindle drives can function as true C axes and in conjunction with the linear axes. Gildemeister offers independent spindle drives, too, on its GMC 20/35/55 mm (3/4-, 1 1/2-, 2 1/8-inch) SM linear series of six-spindle CNC autos.

Yes, it would appear that the CNC multi-spindle automatic is ascending and—with modern tooling practice and programming techniques—is certainly here to stay!