This Giddings & Lewis VTC 1600 is one of two new machines doing the work of four old boring systems at ACIPCO.
ACIPCO's VTC 1600 machines 2,000-lb hourglass-shaped steel pipe-mill rolls, including O.D.s and I.D.s requiring facing, boring, and turning, to tolerances of 0.001 in.
The VTC 1600 at ACIPCO runs on a GE Fanuc control that includes a remote pendant with table jog and tool probe. The machine is also offered with Siemens controls.
THE PERFORMANCE OF 30 TO 50-YEAR-OLD BORING mills at the Number One Machine Shop at American Cast Iron Pipe Co. (ACIPCO) had degraded to the point that operational costs became prohibitive. So the company replaced them with two vertical turning centers from Giddings & Lewis (G&L), one of which was a VTC Series 1600.
The machine sports an 1,800-mm table/chuck and costs slightly more than remanufacturing the old boring machines. G&L recently re-engineered the VTC series, adding performance and today's technology. And in the process, it reduced the number of parts to lower machine price and improve reliability.
"The 1600 performs well and makes us more competitive in the marketplace," says Tommy Blackerby, ACIPCO's assistant superintendent of machine shops. "We've reduced cycle times, saved floorspace, and lessened maintenance costs 90% with the new machines. We spent over $20,000 on parts to maintain the old machines that delivered duty cycles of 24 hr/6 days. The G&L VTCs run 24 hr/5 days and still have extra capacity."
Typically, the Number One Machine Shop cuts materials such as carbon steel, brass, cast iron, stainless steel, and D2 steel. It makes over 100 different parts on the 1600, including steel pipe rolls out of D2.
Steel pipe-mill rolls that are hourglass-shaped form plate steel into pipes up to 100-ft long with 24-in. diameters. The 1600 machines the entire roll, including the O.D. and I.D., which require facing, boring, and turning. Tolerances on the 2,000-lb part are approximately 0.001 in. for its bearing fit. The shop's old machines had a lot of slop, so operators took extra precautions and had to know the ins and outs of the equipment to hold such tolerances.
High dynamic stiffness and damping in its Z-axis headstock and hydrostatic ram allow the 1600 to make such precise, heavy cuts. Its one-piece, thermally symmetric meehanite headstock casting improves machining accuracy over a wide operating range.
Hydraulics elevate and clamp the 1600's cross slide, which is then mechanically secured with 225,000 lb of force on each side. Linear scales in the elevating system ensure accurate positioning and parallelism between the cross slide and table.
The machine's 9.8-in. 2 ram incorporates a noncontact, adjustment-free hydrostatic guideway system for reliability. It handles 100-hp cuts and reaches into minimum bore diameters of 12.8 in.
ACIPCO's 1600 runs on a GE Fanuc control and includes a remote pendant with table jog and tool probe. These functions let operators easily find zero positions and shorten setup time.
"We often stop in the middle of a job to make emergency spare parts, so quick setups are essential," says Blackerby. "The tool probe saves 30% to 50% of setup time because it checks the tool and records the offset in the control. Before, we had to make a test cut and set tool offsets manually."
Giddings & Lewis
FOND DU LAC, WIS.
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