The Japanese machine tool builder, Okuma, has introduced a new,universal cylindrical CNC grinder for chucking or between-centresworking on components up to 300 mm diameter, 650 mm long.Designated GU-34T, the machine is available in the UK throughsole agent, NCMT. The combination of an internal grinding spindlewith straight-approach and angle-approach external grindingwheels allows the most complex components to be produced in oneset-up. As a result, floor-to-floor times are reduced andaccuracy is improved by not having to refixture the part onanother grinder.

The diamond dresser is able to dress both ID andOD grinding wheels and has automatic withdrawal to preventinterference during production.

Swivelling of the internalgrinding spindle into the working position is automatic and thetailstock may be conveniently slid out of the way, rather thanhaving to remove it entirely from the work table.

Internal tapergrinding is achieved by swivelling the headstock by up to 90degrees, with fine adjustment up to 17 degrees being made usingthe table swivel.

Changeover between straight- and angle-approachexternal grinding is effected manually by swivelling thewheelhead through 30 degrees and reclamping, a process madevirtually effortless by a pneumatic head support.

The mountingnut needs only to be loosened, not removed, when changing thewheel.

Two design features are of particular note.

Themaintenance-free wheel spindle has a non-cylindrical, plainbearing which runs in an oil reservoir, ensuring rotationalaccuracy of 0.01 æm.

Contributing further to top accuracymachining is the wide 'V-flat' guideway structure forthe saddle.

Other principal machine specification includes IDgrinding in the diameter range 10 - 120 mm; maximum workpieceweight between centres of 50 kg; grinding at up to 2,700 m/min;and rapid traverse in both the X and Z axes of 20 m/min.

Controlis by Okuma's own OSP-U10G CNC which incorporates asstandard the company's MacMan system, offering a wide rangeof data transfer facilities.

Programs, component and toolingdrawings and parts orders can be made available on-line whileprogress data can be collected fully- or semi-automatically foranalysis off-line.