Faster machining

The approach is to have a series of LTCs (four- and six-spindle configurations are available) setup in a line. Each of the machines is tooled to perform a limited number of operations, unlike the typical case in a machining center-based line (parallel processing), wherein a single machine typically performs all of the operations required to finish a part. So what happens in an LTC system is that the part, which is fixtured to a pallet (which provides the opportunity for five-axis machining through part positioning), undergoes metal removal in a series of machines that can provide "toolchange" in 0.8 seconds, which means positioning another of tooled spindles to the work, not changing discrete tools from toolchanger to spindle. This is a serial processing approach.

Benz admits that in addition to being quick, this approach is somewhat more expensive if there is a simple comparison made of, say, machining center to LTC. But he notes, "Price isn't everything," and goes on to point out that what needs to be taken into account is "the total cost of ownership."

In other words, if it is possible to produce parts much more quickly--in one time study on an aluminum steering knuckle, the job required 143 seconds with machining centers and could be done in 45 seconds with three LTC six-spindle machines integrated with a rotary part transfer device--then the investment may be well spent, Benz adds, "Our machines are used where labor costs are high." Which means that they're used in places where the machinery and equipment need to be exceedingly productive.