Citizen Machinery’s fully integrated laser processing into the turn-milling cycle of its Cincom CNC sliding head turn-mill centres enables near endless possibilities for the creation of geometric shapes or precision holes into solid bar material which has been pre-drilled within the same production cycle or directly into tubular bar material.
The development opens the metal cutting production process to producing burr-free holes as small as 0.2 mm diameter, produce features such as spiral cuts with 0.025 mm kerf width and maintain consistent and accurate radii less than 0.1 mm in corners of slots without any risk of tool wear or breakage. These can also be produced at a far faster rate than can be achieved by a separate EDM process, for instance.
The Citizen Cincom breakthrough opens new design concepts, in particular in sectors such as medical, electronic and micro industries where the speedy, accurate, highly flexible and reliable Citizen CNC sliding head machine can be integrated with the gains and advantages of non-contact laser operations. Laser cutting can offer quick and accurate ‘swarfless’ cutting, the minimisation of any chance of material deflection due to cutting force reaction and the highly precise production of special shapes and forms.
In a recent trial a 150 watt continuous laser head with an air purge to seal and clear the lens was mounted in the gang tool slide of the latest Citizen Cincom L20-Vlll machine in order to be incorporated into the cutting cycle to produce a complete workpiece from tubular material in a single cycle.
The laser system has a separate control and amplifier unit connected to the machine’s Cincom control which applies M-code ‘on-cut’ and ‘stop-cut’ instructions. While solid bar material can be pre-drilled in the machining cycle and the laser used to drill, profile or engrave the component, with the program having precise control over the focal length of the beam in order to maintain the depth of cut, the tubular bar material from which the workpiece was machined in the trial, was fed through an adapted bar feed unit. This allowed standard soluble oil coolant to be pumped at 70 bar pressure through the bore of the material. In this application the flow of pressurised coolant ensured a cool cutting condition, washed away any melted material and localised the laser beam to the 1 mm wall thickness of the component as it was fed at a cutting feed rate of 1,800 mm/min.
The workpiece, produced from 18 mm diameter tube with a 16 mm bore was turned, faced and a single flat milled on the outside diameter. The laser beam then proceeded along and around the periphery using C-axis rotation to create a series of rectangular shaped features that were interlocked allowing the component to extend and retract.
A series of cuts were made to form a mesh and the Citizen logo profiled around the circumference. As a result, once the component was finished and parted-off, it enabled one end to slide axially over a short distance while still being interconnected to the main body.