Twenty-four Cincom sliding-headstock CNC bar autos were installed between last summer and the beginning of this year (2019) by Citizen Machinery UK at one of the two factory units operated by Shannon-based medical component manufacturer, Smithstown Light Engineering.
The major investment followed Smithstown’s receipt of a contract from a multinational medical firm for machining multiple variants of two types of endoscopic device parts from 303 stainless steel bar. Annual quantity is currently 18 million for the production of nine million assemblies.
Managing director Gerard King had identified the business opportunity in 2017 and machined sample parts on a 20 mm bar capacity Cincom L20 installed three years previously to fulfil another contract, which is still running, for turning a 316 stainless steel spindle for a medical delivery device.
Discussions progressed and to develop the process further, he decided to buy on-spec a 12 mm bar capacity Cincom L12, which is of more appropriate size for producing the endoscope parts in short cycle times. The lathe was installed in August 2017 in a second, newly acquired and extensively refurbished unit on the same industrial estate in Shannon, where an extension currently being built will bring the subcontractor’s total factory space to 80,000 sq ft.
Further successful trials continued with the assistance of applications engineers at Citizen Machinery UK’s Bushey and Brierley Hill technical centres, where programs were optimised and early samples were turn-milled. In April 2018, the medical equipment OEM was ready to award the ongoing contract, which by then had grown to its current production level. Further increases are likely, perhaps even a doubling of quantities.
Mr King commented, “The first of the L12s started arriving here in July 2018 and the last ones were on site by January this year. All are operating 24/7. The lead-time from the customer signing the contract and our shipping the first parts in production quantities was five months. Citizen supported us well during this ramp-up phase.
“A lot of the success of the project was down to the partnership that has developed between our engineers and those at Citizen Machinery UK, which incidentally has two application and service engineers in Ireland dedicated to this market.
“Before delivering the machines, Citizen set them up at their technical centres complete with high-pressure coolant, mist extraction and full tooling packages, so they were production-ready when they arrived.”
He added that the Cincom L12s are so accurate, being easily able to hold dimensions to within 5 microns, that with the relatively open tolerances on the endoscope component drawings, a process performance in excess of Ppk 2 is being achieved, better than the Ppk 1.33 stipulated. It means that there is never a need to chase tolerance, so fewer operators are able to attend the 24 bar autos is than would otherwise be needed.
All of the latest sliding-head lathes are equipped with Citizen’s patented LFV (low frequency vibration) software, part of the control’s operating system that assists chip breaking when machining materials that tend to generate long, stringy swarf when they are being turned.
In conclusion Mr King said, “More than one-third of a billion endoscopies are performed every year around the world and we are currently manufacturing about 2.5 per cent of the associated consumables at the premium end of the market.
“There are many medical contracts that involve these sorts of numbers. Now that we have proved ourselves to be capable of realising a mass production facility in a very short timeframe, we are hopeful of winning more high-volume business.
“While medical devices for endoscopy constitute around two-fifths of our turnover, we are also very active in machining coronary delivery devices as well as cobalt chrome implants, with trials in titanium currently in progress, so future projects could involve any of these.”