Increased horsepower and torque highlight Hardinge's SR Series of universal chuck and bar-type turning centers.
Hardinge Inc. has zeroed in on turning machines with chucks in the 6-in. to 10-in. range with the introduction of its SR and RS series of turning centers. According to the company, both machine types address common shortcomings, such as low torque, horsepower and rigidity, among turning centers in that part-working range.
The SR Series of heavy-duty multitasking CNC universal chuck and bar-type turning centers includes the SR 150, SR 200 and soon-to-be-released SR 250. The machines sport 33 percent more torque and horsepower, and 35 percent more speed, than any of Hardinge's (www.hardinge.com) previous turning centers. Other innovations center around machine top plates and tailstocks.
Spindles on the SR 150 6-in. jawchuck (2-in. bar capacity) machines pack 20 hp, 200-ft-lb torque and 6,000 rpm, while spindles on the SR 200 8-in. jaw-chuck (2.5-in. bar capacity) models have 30 hp, 270 ft-lb torque and 4,500 rpm. SR 250 10in. jaw-chuck machine spindles will deliver 35 hp and 450-ft-lb torque.
Hardinge has made its Eppinger ESA 12-station machine top plates more robust than ever, and they permit zero clearance and hands-free set up. The top plates allow shops to adjust every tool station so that they are exactly on centerline with the machine's spindle. Hardinge said no other builder offers such capability.
Hardinge re-designed the machines' tailstocks, and increased their stiffness by 37 percent. SR 250s also feature servo-driven tailstocks with built-in centers for additional functionality, such as if a shop wanted to lock the machine's spindle in place and use the tailstock as a drilling axis.
RS Series super-precision turning centers are collet-ready-spindle versions of the SR machines. Hardinge said it has added vibration control, thermal stability and accuracy to have the RS machines deliver superior part roundness, surface finish and statistical process control (SPC) capabilities. Models in the series include the RS 42 with a 1.625-in. bar capacity, RS 51 having a 2-in. bar capacity and RS 65 with a 2.5-in. bar capacity.
Super precision RS models generate part surface finishes of 8 micro-in., part roundness ranging from 0.000015 in. to 0.000025 in. depending on the model, and continuous machining accuracies (total variation on diameter) of 0.0002 in.
Besides sharing common design features, both the SR and RS machines are built for hard turning/milling parts that have hardnesses to 90 Rc. Hardinge said the machines' are built with its Harcrete-reinforced cast iron bases that provide the necessary rigidity and damping for improved tool life when carrying out such operations.
