MACH 2016Believed to be a world first is Citizen Machinery’s (www.citizenmachinery.co.uk) full integration of laser processing into the turn-milling cycle of a CNC sliding-head lathe, thereby allowing almost endless possibilities for producing geometric shapes in the walls of tubular bar material.

Although the machine was not at the show, a video of it was being shown. Developed by Citizen’s sister company in the USA and due for European launch this year, the machine is designed to satisfy the demand for medical components (not just stents) with its ability to produce: burr-free holes as small as 0.2mm in diameter; features such as spiral cuts with a 0.025mm kerf width; and consistent and accurate radii of less than 0.1mm in the corners of slots — without any risk of tool wear or breakage.

Moreover, such details can be produced far faster than can be achieved by a separate EDM process; and because laser cutting is a non-contact process, there is no deflection of the part being processed.

A demonstration of the process at Citizen’s Karuizawa headquarters, which attracted more than 3,000 people from all over the world, featured a Citizen L20E sliding-head lathe with a nitrogen-gas-assisted 1.5kW laser (with an air purge to seal and clear the lens) fitted to the machine’s gang-tool slide.

The laser system had a separate control and amplifier connected to the machine’s Cincom control. The medical component being processed was machined from 304 stainless-steel tube that was fed through a special bar-feed unit that allowed soluble-oil coolant to be pumped at a pressure of 70 bar through the bore of the material; this flow of pressurised coolant provides a cool cutting condition, washes away melted material and ensures that the laser beam is localised to the wall nearest to it and cannot penetrate the opposite side of the tube. The cutting rate is
in the range 300-400mm/min.

The stent component — produced from 10mm-diameter tube — was turned, faced and then had three equi-spaced flats milled half-way down its length.

Using the machine’s C-axis rotation, the laser then produced a series of features along and around the component’s periphery; these included a series of diamond shapes, a bayonet fitting at the front end, a complex logo and a series of holes as small as 0.12mm in diameter — plus a number of tightly toleranced slots.

Another first for Citizen at MACH was the launch of the UK-developed Alkart CNC Wizard 2016 off-line programming aid for Citizen’s Cincom CNC sliding-head lathes and Miyano fixed-head turn-mill centres.

This latest Wizard development includes all the latest Citizen Cincom machines — with and without a guide bush — as well as the latest BNA-42S, BND-51SY2, BNJ-42 and BNJ-51SY6 machines from Miyano.

New features include improved program data screens, program transfer functions (with calculator functions for chamfering, drilling and grooving, for instance), and feed suggestions for a range of material types.

Machining processes can be selected from the built-in data base; help references, diagrams and calculator utilities are also included.