An integrated 98-tool magazine and toolchanger provide fast changeovers on the Niles-Simmons N 40 MC milling-turning center in use at Caterpillar.
A Niles-Simmons N 40 MC millingturning center increased Caterpillar's production of crank shafts for its 3500 Series 8, 12, and 16-cylinder diesel and gas engines.
When Caterpillar's Engine Plant in Lafayette, Ind., needed to increase production of crankshafts for its 3500 Series 8, 12, and 16-cylinder diesel and gas engines, it looked for new milling/turning centers. Caterpillar's machine shop, engineering, maintenance, tool design, and NC programming personnel all expressed their needs to Bohle Machine Tools Inc., and Bohle suggested a Niles-Simmons N 40 MC milling-turning center.
The machine is rigid, reliable, and accurate with a 134-hp headstock spindle motor and a 40-hp milling/turning spindle motor for machining large precision components. A slant bed with a combination of boxways and linear guideways aid with machining crankshafts. The crankshafts are supported by two steadyrests, which, along with the tailstock, are independently positioned by separate NC axes. Automatic part probing takes place via a radio-controlled probe system and automatically compensates for part deviations.
An intermediate machine in the Niles-Simmons' C Series millingturning line, the N 40 MC has a 78.7 118.1177.1236.2-in. turning length with a swing-over bed of 30 to 31.8 in. and a Y-axis movement of 15 in. In addition, the N 40 MC operates at up to 4,000 rpm, uses position control, and has an integrated cooling system for stabilizing temperatures. The machine's milling head is equipped with a swivel B axis, and its toolchanger includes an integrated 98-tool magazine. The machine also has a tool-management and tool-life monitoring system. The N 40 MC completes a number of operations in only one or two setups, slashing handling time, reducing clamping errors, and increasing accuracy.
The machine, in addition to successfully increasing production of crankshafts, has been used for work on oil holes, counterweight pads, and flange ends, as well as for semifinishing main and pin journals. Caterpillar also plans to use the machine to make prototypes from barstock and for gun drilling 12-in.-deep oil holes.
"This machine can do the work of six of their machines now on-line — including milling, turning, drilling, tapping, gun drilling, and reaming," says Klaus Niemann, president of Bohle.
A variety of machining units can be used to expand the machine's modular design including standard milling-turning-boring heads, a cutting wheel with separate drive for heavy-duty milling, and a boring bar slide for bars up to 78 in.