A next-generation CNC system featuring a touch-screen and a qwerty keyboard were features on the new Cincom D25-VIII and -VII sliding-headstock turn-mill centres being demonstrated by Bushey-based Citizen Machinery UK Ltd (www.citizenmachinery.co.uk).

The D25-VIII is configured as a 10-axis sliding-head machine with a 25mm-diameter capacity.

It incorporates a swivelling B axis (0-135deg) in the first gang-tool-post (X1, Y1 and Z1 axes), which can hold four double-sided driven spindles and access both the main spindle and the sub-spindle.

A second gang-tool-post (X2, Y2, Z2) can work independently or simultaneously with the first tool-post to overlap rough- or finish-turning operations, for instance, or apply drilling- or milling-based cycles in unison.

Further machining flexibility is provided by a (Y3) back tool-post with one fixed or three driven tools offering 90deg adjustment for face, radial or angle machining; there is also an ‘opposite’ tool-post alongside the sub-spindle (X3, Z3), which provides a further two fixed-tool positions.

There is an overall capacity for up to 59 tools. The machine also offers the advantage of removable guide bush for more-economic material use on shorter components.

The power of the main spindle is 5.5kW, with 3.7kW available for the 25mm-capacity sub-spindle; both offer a maximum speed of 10,000rev/min. The gang-driven tools are powered by 2.2kW drives with maximum speeds of 9,000rev/min, while the back driven-tool speeds are 6,000rev/min.

Rapid-traverse rates are 32m/min, with 24m/min available on the Z2 gang tool-post. Low-frequency vibration (LFV) cutting technology for optimised swarf control was a feature of this machine, as well as the newly launched Miyano BNA-42GTYLFV — a ‘hybrid’ 42mm-bar capacity moving headstock turn-milling machine that allows the patented LFV technology to be applied to capacities greater than the 20 and 12mm capacities of Citizen’s Cincom sliding-head machines.

This Miyano machine, which uses the Cincom operating system interfaced to the Mitsubishi-based control platform incorporating Citizen’s Superimposition to allow simultaneous cutting with up to three tools, has a three-axis main spindle (X1, Y1 and Z1) rated at 11kW 6,000rev/min, and a two-axis sub-spindle (X3 and Z3) rated at 5.5kW 5,000rev/min.

Also featured are a single eight-station turret with a half-indexing capability, and a gang tool slide with 13 tool positions, of which three can be powered.

The maximum machining length is 110mm and with the option of multi-holders for tools, a maximum of 45 tools can be accommodated.

LFV is controlled by programming special G-codes at the control to impart the ideal size of chip required to offset problems such as the ‘bird-nesting’ of swarf.

These advantages are achieved by ‘vibrating’ the servo axes in the axial direction, while synchronising this vibration with the rotation of the spindle.

The ‘air-cutting’ introduced by this technique is characterised by the ‘intermittent expulsion’ of fine chips, along with the elimination of problems such as chip entanglement and built-up edge.