A range of multi-tasking twin-spindle, twin-turret turning centres with Y-axis capability on their upper and lower turrets, has been launched into the UK marketplace by Mills CNC: the TT1300SYY (42/51 mm bar diameter capacity) and larger TT2100SYY (65/81 mm).

The Doosan TT1300SYY and TT2100SYY are flexible machines and can be employed in a number of ways. For instance, twin-turret capability allows simultaneous OD and ID cutting to occur on a part located in the machine’s main spindle. Alternatively, the simultaneous milling and turning of components in the machine’s main and sub-spindle enables multiple finished parts to be completed in one cycle, while a further option is to combine operations by machining one side of a part in the main spindle before being finished in (transferred to) the sub-spindle.
Mills CNC’s technical director Tony Dale says: “Doosan TT machines have a reputation in the market for their accuracy, speed and reliability. The new machines, with their dual Y-axis capability, build on this legacy and take these strengths, along with productivity and efficiency, to a whole new dimension.”
As well as having Y-axis capability on their upper and lower turrets, the new machines also feature LM roller-type guides on the axes, up to 40 m/min rapid rates, and 11 kW/6000 rpm/93 Nm spindle performance on the TT1300SYY (15 kW/6000 rpm/ 116 Nm on the TT2100SYY).
Also featured are high capability sub-spindles – 11 kW/6000 rpm for both models – while a low-friction ballscrew design mitigates the effects of thermal drift. Furthermore, both machines feature the Doosan Easy Operation Package for programming, and a Doosan grease lubrication system.
For further information www.millscnc.co.uk

Lathes have many uses, some of which are less conventional than others, like gear skiving. A case in point can be seen at one of Europe’s largest specialist manufacturers and suppliers of gear racks, pinions, leadscrews and nuts, Halifax Rack & Screw (HRS), which has recently started producing round gears at its Brighouse factory in West Yorkshire.

For machining round gears accurately and quickly, the firm has invested in a gear skiving machine: an Okuma Multus U3000-2SW from NCMT. Already installed and operational, this bar-fed, multi-tasking lathe is about to be fitted with automation equipment to further speed the handling of components, free up more operator time and make the process even more efficient.
Sales engineer at HRS, Simon Matthews, who has been heavily involved in the project, says: “For the medium-to-large batch production of gears, skiving has become the technology of choice. For example, in the case of the first three gears we are producing for our US customer, Vermeer, the 25 minute cycle times for the two larger gears would be three to four times longer by hobbing or using other gear cutting machines. We opted for the Multus from Okuma, as it was the first multi-function machine manufacturer to develop a generic platform for skiving precision gears to DIN5 quality.”
A crucial element in gear skiving on a multi-tasking lathe is being able to synchronise accurately the B-axis rotary movement of the upper tool spindle carrying the skiving tool, with the C-axis rotation of the main spindle – functionality for which the Multus is noted.
For further information www.ncmt.co.uk