One of the most capable mill-turning machines ever built, has four turrets, two spindles and offers a total of 13 computer controlled axes. The WTW-150 is for the production of components up to 310 mm diameter /1,070 mm long and has been introduced to the UK by Mills Manufacturing Technology under its sole agency agreement with Nakamura Tome, Japan. The WTW-150 is effectively two opposing twin-turret lathes in one.
The left- and right-hand, 7.5 (5.5) kW spindles are each served by upper and lower 12-station turrets, all 48 tool stations being live with 3.7(2.2) kW of milling / drilling / tapping power.
Various configurations provide spindle speeds up to 8,000 rpm, full C-axis and driven tool speeds to 6,000 rpm.
Both upper turrets can have +/- 30 mm of Y-axis movement for machining slots, off-centre holes or complex interpolated features.
The need for special tool holders when working above and below the spindle centreline are virtually eliminated.
The same turrets may also be equipped with an attachment for rapidly generating chamfered, flat and tapered polygons on any practical part of the component.
The WTW-150 is not only versatile but quick and accurate as well.
Impressive acc/dec figures for the motors powering the spindles, slideway ballscrews, rotation of the turrets and live tool stations allow maximum spindle speed to be achieved in 3.6 seconds.
It will achieve maximum driven tool speed in 0.4 second, rapid traverses up to 40 m/min and a chip-to-chip time of 1.4 seconds.
A massive slant-bed structure and rigid turrets clamped by Curvic couplings enable machining to very close tolerances on this 10.5 tonne lathe.
There are numerous ways of feeding the WTW-150 with material and subsequently removing the machined parts.
Bar magazines for 5 metre stock are of Nakamura Tome's own make and can be supplied for bar diameters up to the size of the spindle bore, which is 52 mm or 47 mm depending on the motor chosen.
Conventional or gripper-type parts catchers are available, the latter intended for components which are longer or need careful handling.
Alternatively, an NC gantry with twin grippers can be supplied for automated loading and unloading parts for chucking up to 130 mm diameter / 130 mm long / 3 kg (x2) in weight.
A further option is a shaft loading magazine for feeding pre-cut lengths of bar from 100 to 1,000 mm through the left hand spindle bore.
A shaft unloader may also be supplied to extract the machined components through the bore of the right hand spindle.
Once in the machine, the bar or billet can undergo a plethora of different machining options.
Some of these include: (i) simultaneous 4-axis front-end machining of identical or dis-similar components at both spindles; (ii) front-end, 2-axis turning of a shaft component at the left hand spindle using a centre in the lower left hand turret followed by part-off and reverse-end machining at the right-hand spindle, either 4-axis chucking or 2-axis centre turning; (iii) balanced cutting of long shafts clamped between the two spindles using all four turrets.
Control is provided by the Fanuc 18i-TA CNC with Nakamura Tome's user interface.
High level software provides automatic part program generation, enabling the most complex machining sequences to be developed, even by novice operators, for maximum productivity at both spindles.
Graphical interactive programming selects the correct tool and data required and calculates the cross positions for automatic programming.
This is assisted by comprehensive tool and material libraries and graphical 3D representation of the component on screen with cutting conditions and surface finishes marked.
Areas which have been machined may be seen at a glance; and tool paths can be checked.
Additional software modules oversee load monitoring, tool life monitoring and sister tool replacement, quick offset input, workpiece datuming, etc.
An alternative, more cost-effective option for one-hit mill-turning is also available from Nakamura Tome.
Designated WTS-150, the machine has two upper turrets and one lower turret serving both spindles.