Over the past decade, Managing Director
Last year the company more than doubled its production area to 8,500 sq ft by moving into an adjacent factory unit. Part of the reason for expansion was to dedicate space for training and developing the skills of the subcontractor's workforce, apprentices and operators from one of its largest aerospace customers that utilises similar machines.
When he started his contract machining business, Nick took the view that for one-hit production of turn-milled parts, sliding-head lathes were able to hold size better than equivalent fixed-head twin-spindle lathes. It is possible to hold five microns total tolerance on most turned and interpolated features.
He already had considerable experience of Citizen Cincom as well as other sliding-head lathes at various subcontract firms in the area, so in 2011 he ordered the first Cincom M32-VIII, which was delivered fitted with a pneumatic guide bush that improves the machine's ability to accept bar stock of variable quality and extends the bar capacity from 32 to 35 mm diameter.
It proved ideal and there are now six similarly equipped models operating around the clock at the Eastwood facility, lights-out overnight. All are fitted with 130 bar high-pressure coolant and a 3.6-metre bar magazine. The latest M32 addition, plus a 20 mm bar capacity Citizen L20-XII with a programmable B-axis and the manufacturer's low frequency vibration (LFV) chip breaking software, were delivered in
Until the pandemic took hold in early 2020, up to 60 percent of turnover was derived from aerospace contracts, but the proportion is more like one-third of that now. The current shortfall in commercial aerospace work, due to Covid-19, has been largely offset by winning new business, primarily from the medical industry. The fall-off in work from the aerospace sector has presented the opportunity to focus more on training, which had been identified as the crucial element for the future development of the business.
Fortuitously, the presence on the shop floor of the L20-XIILFV meant that its superior chip breaking ability could be harnessed for more efficient turning of medical parts from stainless steel bar. The material normally forms stringy swarf that wraps itself around the component and tooling, risking damaging both, but programmable LFV avoids the problem by breaking the swarf into a short, manageable length. The chip-forming functionality in the operating system of the Mitsubishi control is switched on automatically by G-code command for those parts of cycles where it is expedient to use it, and then switched off again automatically, resulting in significant improvements in productivity and yield.
In the case of an early medical job whose dimensional tolerances needed to be within +/- 25 -microm, LFV was switched on for about 25 percent of the cycle. After 1,000 components had been produced, there was no swarf damage to components or tool breakage, even though a 0.8 mm diameter hole was being drilled and reamed in the reverse end of the part.
'Although the volume of our aerospace work diminished at the start of last year, just after we acquired the L20, the machine is proving useful for fulfilling medical contracts. The benefits will be felt even more in the future as the aviation sector recovers, as the stainless steels, titanium alloys and plastics we turn-mill for those customers all benefit from the chip breaking technology.'
Another feature of the machine that
With tongue in cheek,
Contact:
T: +44(0)1923 691500
E: sales@citizenmachinery.co.uk
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