As part of its agency agreement with the Italian machine tool manufacturer Delta, RK International Machine Tools Ltd, Erith (www.rk-int.com), has added two new machines to its range of grinders.

The Delta Rotax 7 Compact and Delta Rotax 9 Compact Plus are both fully automatic rotary-table horizontal-spindle NC machines with applications across a range of industry sectors, including tool-making, automotive, mould-making and bearings. They are also both travelling-column types with pre-loaded hydrostatic bearings on the machine axes.

The rotary table and spindle both feature high-precision double-row angular-contact pre-loaded ball bearings, although the spindle also benefits from the addition of a hydrodynamic bearing on the wheel side; this ensures extremely long life, very smooth rotation and quiet operation.

The spindle, which is driven by a 7.5kW 1,400rev/min motor, can carry wheels up to 400mm in diameter, 50mm wide and with a 127mm-diameter bore; there is the option of a 100mm-wide wheel. The axes are driven by brushless servo motors, while the optional W axis for the wheel dresser is driven by a stepper motor.

Machine control is provided by Delta’s Compact Plus NC, which has been designed to simplify the programming of even the most complex parts. All functions are accessed via the colour LCD screen; the control also has a number of built-in automatic cycles, including those for roughing, finishing and spark-out.

The Rotax 7 and 9 machines have maximum grinding diameters of 700 and 900mm respectively, maximum grind heights (with a new wheel) of 330 and 530mm, and accommodate table loads of 500 and 700kg. The vertical-axis speed of both machines is 1.5m/min; the transverse-axis speed is 0.3m/min.