Filling The Gap Between Single- And Multi-Spindle Machines

What do multi-spindle screw machine users need/want in their next machines? Five features are mentioned most frequently by customers: flexibility; easy changeover from one job to the next; ability to use readily available off-the-shelf tooling; greater accuracy and consistency; and ease of operation and maintenance.

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What do multi-spindle screw machine users need/want in their next machines? A few years ago, engineers from Cone-Blanchard (Windsor, Vermont), manufacturer of the Conomatic multi-spindle automatic, visited more than 100 of the firm's customers for the answers. Five features were mentioned most frequently by the customers: flexibility; easy changeover from one job to the next; ability to use readily available off-the-shelf tooling; greater accuracy and consistency; and ease of operation and maintenance.

Cone-Blanchard incorporated those features in its first CNC multi-spindle screw machine, a three-spindle machine called the Tri-Turn 383 that the firm introduced at IMTS 2000. A marketing program for the new machine was just beginning to develop momentum when Cone-Blanchard, and its sister company, Motch Corp. (Cleveland, Ohio), were sold to DeVlieg Bullard II (Rockford, Illinois), a rebuilder and major supplier of replacement parts for a large number of machine tools whose manufacturers went out of business.

The sale included everything except the Tri-Turn 383, which was retained by Triturn Technologies, Inc. (Cleveland, Ohio), a newly formed subsidiary of Park Corp. that includes many people who had been involved in the development of the machine. J. Hunter Banbury, the former president of Cone-Blanchard and Motch Corp. and a Park Corp. vice president, is the president and CEO of TTI, which is committed to bringing the Tri-Turn project to a successful conclusion.

The Tri-Turn is a true CNC multi-spindle screw machine: It has no cams or change gears. It has three, main, 29-hp, 5,000-rpm spindles with 1.5-inch-diameter bar capacity. The bar can be fed out from the main spindle as machining takes place, simulating the operation of a Swiss screw machine; machining can be kept close to the spindle to minimize deflection and maintain optimum machining results. The machine can also process chucked parts up to 5.5 inches long.

Each spindle is opposed by a counterspindle that allows the part to be transferred back and forth to work both ends of the part. The counterspindle can also serve as a tailstock for long parts, act as a live tool spindle with high (7.4) horsepower and permit a doubling of the live tool rpm by counter rotation.

Each spindle is served by a turret, permitting the Tri-Turn to be equipped with up to 40 turning and rotating tools at any given time. The large tooling capacity enables the machine to hold the tooling required for several jobs to expedite changing over from one job to another. Also, the machine is designed to use standard, quick-change, lathe tooling to expedite tool changes and reduce setup times.

The machine is equipped with a Fanuc 160i-T CNC control. In keeping with the perceived need for programming simplicity, the control has a three-path programming capability that allows the sophisticated machine, with its 16 axes of motion, to be programmed as if it were three, separate, simple, two-axis lathes.

Why a three-spindle machine? "One of the problems with six- and eight-spindle CNC machines is that they are extremely complex to use," explains Mr. Banbury. "The shop that steps up from a multi-spindle automatic to a six- or eight-spindle CNC machine quickly finds that it needs to replace one of its skilled setup persons with a Ph.D. in programming. By contrast, a three-spindle machine is much easier to program, operate and maintain. Each of our spindles operates—and programs—like a single-spindle lathe.

"The three-spindle machine helps fill the gap between one- and two-spindle CNC lathes and CNC multi-spindle screw machines," Mr. Banbury continues. "Our customers still make parts in large quantities, but instead of making two batches of 500,000 parts, they're making 1,000 batches of 1,000 parts. The Tri-Turn gives them the combination of production capability and quick changeover required to meet their customers' needs. The first time our customers run a part it may take them a day or two to program the part, debug the program, install the tooling and so forth. The next time they run the part, they'll be able to set up for it in 20 minutes. Even if tool changes are needed, because our machine uses quick-change tooling, the customer can be set up in less than 60 minutes—and probably less than 30 minutes."

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