Vertical Lathe Has Machining Center Capabilities
UK - Manufacturers are increasingly demanding the capability to machine components in a single set-up to achieve short lead times, improve accuracy and reduce work-in-progress. Aimed at such users processing parts weighing up to 1.5 tons, Okuma has introduced the VTM-80Y B to the UK market through sole agent, NCMT.
The 23-ton machine has been designed as a cross between a heavy duty vertical turning and boring facility and a 5-axis machining center capable of simultaneously interpolating up to four CNC axes.
Structurally it is configured as a bed-type machining center but instead of a conventional table it has a 30 kW turning spindle / table driven via a two-speed gearbox. This offers steplessly variable speeds in the range 4 to 270 rpm (low range) and 8 to 800 rpm (high range). In addition it provides 360,000-increment C-axis positioning.
Two large-cross-section, X-axis slideways carry a substantial column with vertical Z-axis slides. These in turn locate a saddle with Y-axis cross slides to support the 18.5 kW / 4,000 rpm motor-spindle (B-axis). By locking the motor spindle using a Curvic coupling it becomes possible to use it for turning operations without risk of damage to the bearings. The B-axis can position the spindle between vertical and horizontal machining positions in 5-degree increments.
The positioning facility available on the B-axis allows standard tooling to be used in situations where specials might otherwise have to be considered. In addition, it is possible to improve milling efficiency when using ball nose cutters by using the tool at an angle to avoid zero surface speed cutting at the tip. Similarly, angled holes can be produced without the need for special fixtures using a three-dimensional co-ordinate conversion facility within the control software.
In standard form, up to 36 BT50 Big Plus or CAT50 taper tools are stored in a free-standing tool magazine for exchange into the vertical spindle position. Use of a common taper standard for milling and turning provides the opportunity to use certain tools for both types of operation, allowing the machine to drill horizontally as well as vertically, for instance. Tool magazines are available for up to 120 tools and maximum tool weight is 30 kg.
The machine is capable of turning components up to 800 mm diameter and 1,135 mm long. Axis travels are 1,120 mm in X, 1,135 mm in Z and ± 355 mm in Y. Rapid traverse rate is 24 m/min in X and Y, 20 m/min in Z and 20 rpm on the C-axis. Control is by a Fanuc 18iTB CNC system using software developed by Okuma. It provides four axis interpolative control plus positional control of the B-axis.
Options include an automatic pallet change system for up to 8 pallets, allowing the machine to be configured as a semi-automated, stand-alone machining cell.
SOURCE: NCMT Limited