For many people in metalworking, the term training evokes a Norman Rockwell-type image of a white-haired old timer showing a young, somewhat attentive apprentice how to run a machine on the production floor. If you are a machine operator, you probably received your training on the job working under the watchful eye of an experienced operator.

That kind of training may have been adequate a generation or two ago. However, as machine tools have become more sophisticated (and expensive) and as tolerance for errors of any kind in the machining process approaches zero, more formal training programs are becoming a more attractive training alternative for small shops as well as large manufacturing concerns. One reason is that they provide a more complete and comprehensive coverage of the material; the trainee benefits from a complete, well-thought-out program, presented and reinforced in ways that help him or her retain the information presented. Another reason is that formal training programs include tests that confirm whether or not the trainee is learning the material. Still another reason is that they provide an alternative to tying up operators and machines for basic training.

A formal training program became an important part of a long-term strategy for modernization and growth at Eaton Corp.’s Aeroquip Fluid Conveyance plant in Jackson, Michigan. The plant produces aerospace hoses and fittings for fuel lines, hydraulic lines and other applications. It supplies hoses, fittings and quick-disconnect couplings for military aircraft programs such as Lockheed Martin’s Joint Strike Fighter (JSF) and F-35 supersonic multi-role fighter, the U.S. Army’s new RAH-66 Comanche helicopter, Boeing’s C-17 cargo transport, and for commercial aircraft programs such as the Airbus A380.

The Aeroquip Fluid Conveyance plant includes a machining department that machines aerospace hose fittings from stainless steel (primarily), titanium and aluminum. It also has a fabricating department for welding and tube bending, and an assembly department where the machined fittings are added to the hoses and tubing.

Years ago, the plant machined the fittings on multi-spindle screw machines, for inventory. Lot sizes averaged about 500 pieces–much smaller than jobs usually run on multi-spindle machines. However, the machines provided the capacity for large jobs when needed, and the machining department was staffed by skilled and experienced multi-spindle screw machine operators and setup people who knew how to get the best from their machines. The system met the No. 1 goal of producing quality parts, for which management was willing to accept a little production inefficiency.

Eventually, however, the plant began to adopt lean manufacturing practices, and a decision was made to reduce finished product inventories. Lot sizes for machined fittings became smaller, necessitating more frequent setups, resulting in a situation where the multi-spindle machines were idle for setup changes more often than they ran. As lot sizes continued to shrink, the inefficiency of running the small jobs on multi-spindle screw machines could no longer be tolerated. Management began looking for a new machining strategy.

At the time, the plant had a small NC machining department built around two four-axis, CNC lathes made by Mori Seiki USA, Inc. (Richardson, Texas). The machines combined the ability to produce complex parts complete in one setup with more efficient production of small lot sizes, so the company made the decision to replace its multi-spindle cam machines with more four-axis CNC lathes. (Four chuckers would be retained for large jobs.)

Four Mori Seiki four-axis lathes were added to the two from the plant’s NC department. Randy Smith, senior manufacturing engineer for the machining department, explained the company’s selection of the Mori Seiki CNC lathes: “Our parts require a lot of machining on both ends,” he notes. “With most four-axis CNC lathes, the sub-spindle has less horsepower than the main spindle. Our lathes have the same horsepower on both spindles, permitting side two of the part to be machined in the secondary spindle at the same speeds and feeds as side one in the main spindle. Since most of our parts are stainless steel, and since that second side frequently needs as many operations as the first side, we need equal horsepower on both spindles.”