The Puma 480 and the Top- Turn S50 are two turning machines that easily handle the big stuff.
The Puma 480 accomodates parts to 25.6 in. in diameter and as much as 40-in. long, while its sister machine, the 480L, accepts part lengths to 80.4-in. long. The drawtube I.D. for both models measures 6.55 in.
For large bore, long workpiece applications, the Top-Turn S50 packs a 12-in chuck, 25-in. center height, 50-in. swing over bed, and travels of 26 in. in X and 78 in. to 236 in. in Z.
An addition of C-axis and Y-axis capabilities makes the machine ideal for precision turning and milling parts such as large-sized printing rollers, straight-toothed shaft couplings, main shafts, main-shaft bearing caps, yokes, scrolls and other large-diameter, long parts. With 60-hp of turning power, 2,975 ft-lb of lowend torque and as much as 6,870 lb of Z-axis thrust, Doosan Infracore’s (www.doosaninfracore.co.kr) Puma 480 tackles heavy and interrupted cuts.
Its headstock casting is mounted on the same ground surface as the tailstock to maintain perfect alignment and center height. A double row of cylindrical roller bearings on either side of duplex angular thrust bearings support the machine’s heavy-duty cartridge-type spindle. The cylindrical roller bearings feature large contact surfaces for high rigidity in heavy cutting.
A two-speed gearbox generates speeds to 1,500 rpm and powerful low-end torque. The gearbox and motor are isolated from the spindle to eliminate the transfer of heat and vibration.
The 12-station turret on the Puma 480 employs a large 12.6-in.- diameter Curvic coupling and exerts 26,200 lb of hydraulic clamping force. Indexing repeatability is +/- 0.0005 degrees.
A high-torque index motor controls turret rotation, deceleration and clamping. The turret indexes non-stop and is bi-directional with a 0.25-sec next-station index time.
Top-Turn S50 machines, from Centric International Inc. (www.centric-intl.com), offer standard extra-large spindle bores of 9 in. in diameter. There can be front and rear chucks to securely fasten workpieces and decrease swaying during rotation. A special gear ratio enhances the horsepower and torsion of the spindle nine fold, said Centric, to reach a full 270 hp.
As standard, S50 machines include Baruffaldi brand servo turrets with 12 stations, 1.57-in. shank heights for square tools and tool shank diameters of 2.36 in. Their electromechanical TB Series turrets operate using brushless servomotors for reduced indexing times, directional rotation and shockless positioning.
As optional, S50’s can sport magnetic drives for linear travel of over 5-m long on the Z axis. This eliminates the need for a conventional ballscrew control, which may have shortcomings in such long Z-axis travels. These shortcomings can include slow movement and late feeding-mechanism responses, as well as torsional and gravitational strain. The magnetic drive lowers the center of gravity, increases response times, saves energy and operates at low noise levels.
