Star SR-20RIII boasts impressive capabilites

A defining feature of the new Star SR-20RIII lathe compared with the RII model is its ability to drill a hole down the center of a 20 mm diameter bar to a depth of 100 mm, using the 3.7 kW/10,000 rpm main spindle in conjunction with two additional front-facing tools mounted next to the opposed spindle. Another key feature is the Fanuc 300iS CNC with motion control, capable of very high speed cutting cycles for relatively simple turning operations when running programs created and optimised off-line using powerful computer-aided manufacturing software from Star. Conventional ISO programming and computer numerical control is reserved for producing more complex components. Further promoting high productivity are 35 m/min rapids in all linear axes, higher than on the RII and equivalent to the fastest machine in Star’s range, the SR-10J. C-axis positioning of the main and sub spindles in 0.01-degree increments is similarly fast at over 9 revs per second. Despite the RIII’s agility, it is a robust machine weighing 2.2 tonnes, capable of achieving very high accuracy and surface finish. Spindle cooling ensures thermal stability and also contributes to high precision machining. The working area can accommodate a large number of cutters in addition to the deep hole drills and the usual six ganged turning tools above the guide bush. They include four front-facing and four rear-facing end-working tools in the main sleeve holder; up to 10 live cross-working stations, some of which may be swapped for more end-working tools or other attachments such as for angle drilling, hobbing or roller burnishing; and an independent, four-spindle back-working unit with live and stationary positions. The design of a new product is not complete these days without measures to reduce its environmental impact. Elimination of hydraulics on the SR-20RIII saves energy and oil. Operational noise levels are lower due to the use of low-noise spindle bearings, the life of which is extended by double air purge of the guide bush and back spindle bearing.