Shigiya offers its GSU series of universal grinders designed for versatility with an NC wheelhead swivel function, which enables selection of nine different wheelhead installation patterns. This feature reduces the number of processes needed to perform a variety of multi-grinding tasks. For additional flexibility, two grinding wheels can be mounted onto two wheel spindles, in contrast to conventional machines that mount two wheels onto one spindle. The wheelhead swivels at high speeds using a direct-drive system, and provides high positioning accuracy without backlash.
The series offers two grinder models. The GSU-30B features a 300-mm-diameter swing over table as well as the choice of a 500-, 750-, 1,000- or 1,500-mm distance between centers. The GSU-40B has a 410-mm-diameter swing over table, and offers a 470-, 720-, 970- or 1,470-mm distance between centers. In addition, a model with a 2-m distance between centers is available to grind long parts such as aircraft landing gear. Both models use 510 × 50 × 127-mm (OD × W × ID) wheels. Grinder speeds can be changed steplessly on the AC servo motor to within a range of 15 to 600 rpm. An interactive automatic programming system automatically determines the optimal rotational speed for each workpiece.
Ground for rigidity, the non-concentric hydrodynamic bearings secure the optimal wedge angle, providing precise wheel rotation. The tailstock is mounted with a large-diameter spindle to further ensure precision during heavy grinding. A helical compression ring offsets heat expansion in the workpiece, and an isolated lubrication oil tank avoids thermal displacement in the machine itself.
Also available is an optional, closed-type hydrostatic slide wheelhead feed and a work spindle rotation direct drive to perform eccentric OD and non-concentric OD (polygonal) grinding using the C-X-axis control.