New heavy duty machine takes the philosophy of the A20, Citizen’s most successful new machine launch, into a larger material size category, enabling parts up to 320mm long to be machined in a single chucking.

The Citizen A32, like the 20mm capacity A20, is targeted at heavier duty single operation machining cycles with a 7.5kW main, 3.7kW two-axis subspindle and 1kW motors to power its driven tools.  It is fast with 45m/min rapid traverse rates, more than double previous 32mm machines and has all the advantages of Citizens Streamline Control software to minimise non-cutting times by providing axis motion overlap and direct C-axis indexing. It also introduces network control of NC programs.

To ensure high metal removal rates when cutting with two tools simultaneously, a totally new heavy duty bed casting that is very compact and with high level of torsional rigidity, means there is 30% advantage added to this machine in overall rigidity to enable  the creation of chatter-free and uniform machined surfaces. And, in order to cater for increased productivity, the swarf discharge volume capability has been increased significantly.

As standard 23 tools can be carried on the new machine, six for turning and four are driven for cross machining from the two-axis crosslide. In order to accommodate heavy milling, one driven tool position has higher torque and can be interchanged with a unit able to carry three face driven spindles. Mounted on a substantial overarm attached to the crosslide, are four tool positions for drilling at the main spindle and four for back drilling at the subspindle. 

As an option to further improve flexibility, two front and two back drilling positions are available. An independent gang tool post also carries an additional five tools for back drilling of which four can be driven. By taking advantage of the options available on the machine, with up to 27 tools can be carried on the A32. 

The built-in spindle configuration for both main and subspindle extend the high accuracy, low noise, low energy advantages of the A32 and increase the stability of the machine when running up to 8,000revs/min. To support the 40% improvement in torque available larger bearings and the thickness of the spindle has also been increased.

It is the Citizen Streamline software running on Mitsubishi control hardware that enables the advantages of heavier cutting cycles to be enhanced with higher speeds, overlapped machining and the creation of smoother movements with shorter idle times. Direct C-axis indexing can also save seconds on a cycle by indexing the spindle position during its rotation.

Meanwhile, an axis overlap feature initiates the next axis movement prior to the current motion being completed. Start up times and switching times are considerably shorter with the added advantage to the operator of immediate visualisation on the screen. A high speed program check function at the control enables confirmation of syntax without the machine being operated. The screen layout has also been remodelled and is now compatible with the network LAN that enables full network control of NC programs.
www.citizenmachinery.co.uk