On the occasion of Citizen Machinery UK’s official opening of its Turning Centre of Excellence in Brierley Hill on 15th July, the company launched a new CNC sliding-head lathe, the 12 mm bar capacity Cincom L12 Type X. It is intended primarily for production of dental abutments and implants, but is also well suited to manufacturing parts for the medical industry in general.

For efficient abutment machining, a minimum of five rear-facing endworking tool positions including driven stations are required, as well as the addition of a Y2-axis to the X2 and Z2 movements on the counter spindle to match the three degrees of freedom on the main spindle. All these prerequisites are provided on the L12-X. Previously, to obtain this level of functionality, a user would have had to purchase a 16 mm or even 20 mm capacity lathe, unnecessarily large and expensive for production of such slender components.

Citizen’s patented LFV (low frequency vibration) chipbreaking software in the control is optional and recommended for machining the exotic materials prevalent in dental and medical applications. By vibrating the X and Z servo axes in the direction of cutting in synchrony with rotation of the spindle, problems arising from stringy swarf entangling around the workpiece and tool are avoided. The function, which now has three modes, may be used with static and driven tools. It is especially helpful when grooving, drilling deep, small diameter holes, and most recently also for internal and external thread cutting.

A modular tooling system has been adopted for the gang and back tool posts and an extensive variety of tooling layouts is possible, which includes the ability to drill angled holes. The maximum number of tools that can be deployed is 38.

Unlike on other Cincom L12 models, a built-in 12,000 rpm motor drives the counter spindle, reducing acc/dec times for higher productivity. Rapid traverse in all axes of 35 m/min contributes further to minimising idle times. The new machine is also wider, providing better access to the working area. Rigidity of construction is evidenced by the 2.2 tonnes installed weight and the footprint is compact at 1.84 by 0.97 metres.

Two new sliding-headstock, twin-spindle, turn-milling centres of 32 mm bar capacity have been added to Citizen Machinery’s Cincom programme. Designated L32-X LFV and L32-XII LFV, both feature the firm’s patented, low frequency vibration software in the control’s operating system that acts in two axes to convert what would normally be long, stringy swarf into short, more manageable chips. It is particularly helpful when machining stainless steels, plastics and copper and can be applied not only to turning but also to grooving, thread cutting and drilling.

Unlike the two other L32 bar autos in the range, the 8-axis L32-X adds a Y2 axis to the Z2 axis on the back tool post. So also does the 9-axis L32-XII, which additionally has +90 / -45 degree B-axis swivel on the front gang tool post, whose rotary tools can work at either spindle to produce angled holes. Both machines are available in 35 mm and 38 mm bar diameter versions and all may be used with or without the guide bush to suit the application.

The new L32 design is modular, enabling a user to optimise their manufacturing costs by selecting functions that achieve the ideal machine configuration for their needs, while retaining the option of being able to add extra functionality later. A workpiece conveyor is standard equipment. Control is by the Industry 4.0-ready Mitsubishi 800 CNC system, which allows up to three tools to be in cut at the same time.

Up to 44 tools for front, back and cross machining are available in the -X model, while the B-axis -XII version accepts four fewer. Speed range of the 3.7 / 7.5 kW main spindle and 2.2 / 3.7 kW counter spindle is up to 8,000 rpm. Both have a C-axis for use in conjunction with driven tool stations in the three tool carriers. Fast acceleration of tool rotation up to 6,000 rpm minimises cycle times. Rapid traverse in the linear axes is 32 m/min except in Y2, which moves at 24 m/min.

A new, twin-spindle, 10-axis CNC turn-mill centre, the Miyano BNA-42GTY LFV, has been introduced by Citizen for manufacturing complex components in one hit from bar stock up to 42 mm diameter. The hybrid machine is of fixed-headstock design, but the head is also able to move in and out of the working area for extra versatility, similar to that offered by a sliding-head machine operated in non-guide bush mode.

The 8-station, 3-axis turret including Y-axis movement has a half-indexing mechanism that allows tools to be mounted at up to 16 positions, while multiple toolholders can further expand the number of cutters deployed. There is also Y-axis travel on a gang toolpost, giving extra flexibility when machining at either spindle, especially as the counter spindle moves in the X-axis as well as the Z-axis.

In total, up to 45 tools can be resident in the working area. A superimposition function within the Mitsubishi M730VS control provides the possibility for shortening cycle times even more by enabling up to three tools to be in cut simultaneously at both spindles.

The 3.74-tonne BNA-42GTY enjoys the same rigid, high precision build and thermo-symmetrical design as other lathes in the Miyano range, leading to high accuracy machining. Slideways are hand scraped in all axes and have exceptional damping characteristics, enabling heavy metal removal and helping to prolong tool life. Machine specification includes a 6000 rpm / 11 kW main spindle with 0.001° C-axis, a 5000 rpm / 5.5 kW C-axis counter spindle and feed rates up to 30 m/min.

Numerous options are available to add to the flexibility of the turning centre, including high-pressure coolant, spindle air blow, chip conveyor, parts catcher, parts conveyor and drill breakage detection. Likewise, the capable control can be augmented with the addition of helical interpolation, corner radiusing, synchronous tapping and multiple canned cycles.

The BNA-42GTY is the first Miyano machine to gain the benefit of Citizen’s LFV chipbreaking software, until now exclusively provided on the manufacturer’s Cincom Swiss-type lathes. The patented, two-axis chipbreaking functionality is part of the control’s operating system and involves the axis servo drives and spindle drives.

The position of the tool tip is oscillated by 20 microns, just sufficient to break the swarf. The number of oscillations per revolution (mode 1) or the number of revolutions per oscillation (mode 2) determines the length of the swarf removed from any type of material. The user can define the exact chip length in the program, giving the ability to choose the optimum size for the swarf conveyor to handle efficiently.

The more exotic and difficult to chip the material, the more effective LFV is. It means that high pressure coolant is not needed to assist in breaking long stringy swarf, such as that generated when machining such materials as stainless steel, copper and plastic. So it is no longer necessary to stop the cycle to remove accumulated swarf that is hampering the machining process. Shorter chips also take up less room in the swarf bin, so it needs emptying less frequently.

In some applications, particularly when processing exotic materials, productivity can be increased fivefold due to not having to stop the machine repeatedly to clear swarf that has entangled itself around the tool or workpiece, or both.

With LFV there is an element of air cutting, which allows more coolant to access the point of contact between the tool and the material. Enhanced coolant penetration lowers the operating temperature of the tip, so it can last five or even 10 times longer. This is especially the case if, as frequently occurs on other makes of CNC lathe, a chipbreaking macro has been written into the program. These are notorious for causing rubbing of the tool, built-up edge, machining inaccuracy and premature failure of the tip.

An LFV oscillation results in a turned face that is no longer flat by an amount measured in microns. The machine control knows where the oscillation took place and on the second revolution the high spot on the face is turned away. If required, on the third revolution the tool will finish that process to eliminate the waviness completely at that location.

As an element of air cutting – albeit miniscule – is introduced by LFV, productivity can be slightly reduced when the function is switched on. However, it can be turned off at the control, allowing the possibility of maximum output during attended day shifts when an operator is present to clear swarf. It may be, however, that these machine stoppages lower production output by more than LFV.

Switching the function on at night allows a ghost shift to be instigated without fear of swarf build-up automatically halting production during unattended running. So a manufacturer is virtually guaranteed a full shift’s worth of good components on arrival the next morning.

Installation by Citizen Machinery of a fixed-head Miyano BNE-51MSY twin-spindle, twin-turret turning centre at electrical wiring conduit manufacturer ABB Cable Management Product, Coleshill, heralds a fundamental change in the way the company turn-mills its cable end fittings.

Cycle time savings of up to 70 per cent with more to come, reductions in manufacturing cost, scrap and returns, and elimination of the need to outsource 10 per cent of production to subcontractors will combine to amortise the cost of the Miyano well within 18 months of its installation at the beginning of January 2019. Manufacturing unit manager Andrew Fellows describes this payback time on a major item of capital expenditure as “brilliant”.

Every week, 100,000 metres of flexible metal conduit and 65,000 metres of nylon conduit find their way predominantly into the automotive, rail and mining industries across Europe, the Middle East, China and as far afield as Australia, while some are destined for installation in the parent group’s robot systems. From these numbers it is clear there is a high demand for the mainly brass fittings, plus some stainless steel, aluminium and plastic varieties, that are needed at both ends of every length of conduit.

Fittings needed in large volumes are produced in-house on six cam-type multi-spindle autos, while the shorter runs are completed on four single-spindle, single-turret CNC lathes and now the Miyano twin-spindle, twin-turret turning centre, which replaced a similarly specified, ageing model on which one of the turrets was defective.

Comparing the performance of the latter two lathes, Mr Fellows advised, “In the first two weeks of the Miyano arriving, we transferred onto the new machine the manufacture of four fast-moving products, all of which benefitted from drilling on both end faces simultaneously at the main and counter spindles.

“Average cycle time saving was 59 per cent. The largest reduction was 70 per cent in the case of a fitting that previously required 133 seconds to produce. The turn-mill cycle now takes 40 seconds to complete on the Miyano.”

Senior operator Dan Gardner added, “We have only taken advantage so far of cutting with two tools at a time, but the superimposition function in the Mitsubishi M730VS control, coupled with Y-axis movement of the upper turret and X-axis travel of the counter spindle, allows three tools to be in cut at the same time.

“After five days’ training from Citizen, both on- and off-site, we carried out a time study on a complex fitting that will see an 80 per cent reduction in cycle time from 230 to 46 seconds.”

He went on to describe a further benefit that comes from the ability to have 6,000 rpm live tools with 20 Nm of torque at all stations in both turrets, a total of 24 positions. Whereas 85 per cent of production on the single-spindle lathes is currently from hexagonal bar, the plan is to reduce this to zero in favour of round bar over the coming years as the machines are upgraded and powerful driven cutters are able to mill the flats economically. This process is starting with the Miyano.

The main advantage will be longer service life of the lathes and of the bar magazines feeding them due to the absence of interrupted cutting of hexagonal stock and hence lower vibration levels. In the case of the Miyano, it will also allow round bar at the full 51 mm diameter capacity to be rotated in both spindles at the maximum speed of 5,000 rpm, whereas it would need to be backed off by 75 per cent to run the largest possible size of hexagonal stock. For this reason, such material currently machined on the BNE-51MSY at Coleshill is restricted to 38 mm, which can be rotated at full speed.

Mr Gardner advised that despite utilising mainly hexagonal stock at present, the rigidity provided by the Miyano machine’s bed, hand-scraped box slideways, spindles and turrets is nevertheless sufficient to allow total tolerances down to 30 microns to be held on fittings, a level of accuracy needed for explosion-proof and watertight conduits.

Data collection and display on dashboards of overall equipment effectiveness has been instigated by Mr Fellows since his arrival at the factory in July 2018. Optimisation of every aspect of around-the-clock production has resulted in 24 per cent more output in five days than was achieved before in seven days, lowering manufacturing cost by 17 per cent and raising competitiveness.

Installation of the Miyano, with its elevated level of productivity, will improve these figures further. So also will the imminent arrival of a presetter for off-line tool setting, which will cut two-thirds to three-quarters off the present 60-minute changeover time for the next batch run, which can be as low as 50-off.

According to Mr Fellows, selection of the Citizen Miyano BNE-51MSY was down to the capital cost being 30 to 40 per cent less than two alternatives considered by ABB Cable Management Product, in line with company policy. Lead-time from order to delivery was also the shortest at just 12 weeks.

Just thought I would send you an update on what’s gone on since the launch day.

On Thursday 23rd of May I raced in the Ryton Pools 5mile road race. I had a really good race feeling strong throughout. I was able to win the race in 30.18s. This time shows my running has had a massive improvement over the winter. After looking at the power of 10. I have posted the 3rd fastest time for a U23 so far this year.

At the weekend I Raced in the British Super Series at Blenhiem palace.

My swim was never going to be anywhere near what it should be due to the nerve damage. I ended up coming out the water 1 minute down on the front girls.

The bike leg, all I could do was put my head down. I worked hard with a couple of girls and ended up coming into T2 in 1st. My Biking is feeling really strong at the moment.

On the run I was able to hold on to 4th, happy with the progress but still improvements to be made. My run time was 2 minutes faster than last year.

Thanks so much for all the support.

My next race is Two Castles 10km Road Race this weekend.

Patented swarf management software allows extended unattended production

Since moving premises in Bicester at the beginning of 2015, subcontractor SRD Engineering has approximately trebled its turnover and headcount, a rate of growth that accelerated during 2018 due to the arrival of three new sliding-headstock (Swiss-type) CNC turning centres from Citizen Machinery.

Joining a 20 mm bar capacity Citizen Cincom L20 Type VII lathe installed in 2009, which helped the contract machinists to weather the recession, two further models for processing similar size stock were installed in March and August last year, followed by a 32 mm capacity machine in November. It is noteworthy that the decade-old lathe is currently running 24/7 and still holding tolerance well.

Top precision machining is essential in the 18,000 sq ft Bicester factory, as 60 per cent of the company’s business comes from Formula One, with most of the remainder received from customers in the aerospace and electronics sectors. Dimensional and concentricity tolerances down to 6 microns are held on some 50 to 60 mm long, 3 mm diameter components, for example.

To help achieve this level of accuracy reliably, even during unmanned running, all of the latest sliding-head lathes are equipped with Citizen’s LFV (low frequency vibration) functionality – www.youtube.com/watch?v=2tpgc_pHRl4. The patented system allows stringy swarf generated when machining aluminium, stainless steel, nickel alloys, copper and plastics to be broken into shorter chips, the length of which can be controlled by the cutting program.

Mark Bonham, joint managing director with his brother Paul of the 30 years established, family owned precision machinists commented, “We had no hesitation in choosing the LFV option on the new Citizen lathes, as being a subcontractor we have to process a broad variety of materials.

“Often they are not short chipping and it is difficult to break the swarf using chipbreaker geometry on the cutting tool and/or high-pressure coolant.

“With LFV, which acts in two CNC axes simultaneously and is part of the control’s operating system, as distinct from a macro in the part program, it is possible to regulate chip size closely without compromising the life of the cutters – in fact, they tend to last longer and break less often.”

He explained that not only can the length of the chip be specified in any given program according to the material being cut, but LFV can be applied to different parts of the cycle, for example when turning a deep groove in stainless steel, an operation that is particularly prone to producing a tangle of swarf. It avoids a ‘bird’s nest’ forming around the sub-spindle and inhibiting synchronous component pick-up for reverse-end machining, or entanglement of a tool leading to its breakage or compromised component accuracy and surface quality.

The reason LFV is not necessarily applied continuously to a whole program is that the technology lengthens slightly those parts of the cycle due to repeated periods of air cutting lasting microseconds. It is this action that breaks the swarf into short chips and it also has the effect of improving penetration of coolant to the cutting zone, which is a prime reason for the extended tool life.

If a job is particularly price-sensitive, LFV use can be minimised or even switched off during manned operation, but the system is so flexible it can be reintroduced for lights-out running to ensure a full ghost shift’s production in the bin the next morning, without fear of stringy swarf impairing turning and drilling efficiency and possibly recycling from the conveyor back into the working area and jamming the machine. Thus a weekend’s worth of parts can be reliably produced, whereas without LFV there is a likelihood of only four hours of output before the lathe stops automatically in the absence of an operator to clear the swarf.

Mr Bonham added, “LFV chipbreaking is a huge selling point for Citizen turning centres. We visited their headquarters and showroom in Bushey to see a demonstration and it was clear that the technology is able to resolve a lot of difficulties related to swarf management and temperature control when turning and deep hole drilling. The benefits include better accuracy of machined components and longer tool life.”

The impetus last March for installing a 7-axis Cincom L20 Type XII LFV with a Y-axis on the counter spindle and a 135-degree B-axis spindle integrated into the gang tool block for both front and back machining was down to the original Swiss-type lathe being fully occupied, while enquiries kept coming in for large volume runs of typically 10,000-off per month. One of the contracts won involves producing a two-part, press-fit assembly with a threaded insert that forms a stainless steel oil restrictor used in the aerospace industry.

The machine is more or less devoted to this ongoing job, so a Cincom L20 Type VIII LFV was purchased on spec five months later and was immediately busy producing diverse parts for a number of existing and new customers. It was at this point that the Bonham brothers and their father Steve, who is still active in the business, really appreciated how much money can be made using this type of manufacturing plant.

As a rule of thumb, they noted that the cost of a Swiss-type lathe is around twice that of a fixed-head machine, but the former is able to produce twice as many parts, allowing a subcontractor to invoice around double the amount per month per machine compared with fixed-head capacity. Earnings per pound invested is therefore equivalent. The big saving is that one operator is able to attend all four of SRD Engineering’s Cincom sliding-head turning centres, whereas to achieve the same output from double the number of fixed-head lathes, which have to be individually manned for F1 work, eight operators would be needed, resulting in much higher labour costs.

With this in mind and having received a request to quote for producing 10,000 one-inch diameter Nylon fasteners per month, a 32 mm bar capacity Cincom L32 Type VIII LFV was sourced from Citizen last November and has been machining the parts ever since. Here again, low frequency vibration chipbreaking has proved invaluable for keeping production going during periods of unattended running.

Nine orders to the value of £2 million were placed at Citizen Machinery UK’s first open house at its new Midlands turning centre of excellence in Brierley Hill. The order total is likely to double in the immediate aftermath of the event. Attendance over the three days (14th, 15th and 16th May) exceeded 300, a record number. Visitors looking to upgrade their sliding- and fixed-head CNC turning capacity were welcomed from OEMs and subcontractors throughout the UK and Ireland, as well as from continental Europe.

Four products were launched, all of which benefit from Citizen’s patented LFV chipbreaking software. They were the new L32-X, L32-XII and D25-VIII Cincom sliding-head bar autos on which the software is optional, and the Miyano BNA-42GTY, the first Citizen fixed-head lathe to have the addition of LFV in the operating system of the Mitsubishi control.

A further 11 machines were on display cutting metal, one of which, a Cincom L20, was equipped with a low-cost, automatic billet load/unload system instead of a barfeed. Most of the lathes had a sheet attached to illustrate the annual profit achievable if a customer purchases the machine and produces the demonstration part over 10, 15 or 20 hours per day. All examples showed a healthy margin.

In the best case, when machining a £2 brass part in a cycle time of 40 seconds for 20 hours a day on a 42 mm capacity Miyano BNA-42S2 fixed-head turn-mill centre, subtracting the machine cost per year from the income from production of the component resulted in a profit of £881,520 per year, ignoring operating costs.

The open house featured a Made in the Midlands networking event on the last morning, in which 50 people from local member companies participated. Representatives from each firm introduced their business and learned more about Citizen and its products. Interestingly, it was revealed during the presentation by Citizen Machinery UK’s deputy managing director Darren Wilkins that the revenue generated by the machine tool division of the global business has recently overtaken that of the famous watches.

He was also proud to announce that sales in the UK and Ireland in 2018 were at a record high at 164 machines, propelling the company to market leader for the supply of bar turning automatics; while the first quarter of 2019 saw it also become the leading supplier of sliding-head lathes in UK as well as the whole of Europe. Much of this success is down to the introduction of LFV software on the Cincom platforms.

A party was held on the Wednesday evening to celebrate the opening of the new premises, at which Citizen watches were presented to consultants involved in the design and construction of the building extension. Entertainment was provided by a band whose Birmingham-born lead guitarist Ian Parker has established himself as one of the UK’s foremost blues artists.

Supplier company presence at machine tool open houses is not new, but few host as many as this event. Twenty firms were represented and unusually, four of them have permanent display booths adjacent to the new showroom: Citizen Finance, headed by John Lane; workholding specialist Hainbuch; tooling supplier Floyd Automatic Tooling; and 1st Machine Tool Accessories, which in addition to selling workholding equipment is the UK agent for Iemca bar magazines, which are fitted to most Citizen lathes.

Other equipment providers were: Arno (parting-off and grooving tools), Bison (chucks, tooling and workholding), Blaser Swisslube (cutting fluids) and its UK supplier Jemtech, Cromar Metal Products (swarf conveyors), Filtermist (oil mist extraction), Firetrace (fire suppression), Guhring (cutting tools), Heimatec (tooling systems), Hydrajet (high-pressure coolant systems), J&S Engineering (swarf processing), LNS (bar feeding and swarf management), Mikron (automation and tooling), NTK Cutting Tools (tooling), Sandvik (tooling), Wieland (copper and copper alloy materials), and Wogaard (coolants).

MEGAN MCDONALD has an additional sponsor, CNC turning machine company Citizen Machinery UK, to help her rise in the ITU rankings for elite women triathletes from her current position of 667th in the world.

Now 21, Megan has performed consistently well in triathlons over the years and showed much early promise. She started racing at the age of eight and in 2012 competed in no less than 14 events, coming first in five of them. In 2014, as a competitor in the Junior Women category, she won the London Triathlon in a time of 1 hr 11 min 40 sec, came 3rd in the European Junior Triathlon in Nottingham and 7th in the European Junior Triathlon France in Vierzon.

After moving up into the Elite Women category, she completed the 2016 GBR Sprint Triathlon National Championships in Liverpool in 1 hr 4 min 46 sec, coming 14th, and a year later was placed 24th in the Holten ETU Sprint Triathlon Premium European Cup in the Netherlands.

More recently, Megan qualified to represent Great Britain in the 2019 Pontevedra ITU Cross Triathlon World Championships on 30th April in north-west Spain.  She came ninth after competing against the best under 23s in the world, and 23rd in the Elite Women category. The event comprises a 1 km swim, 30 km off-road cycling leg on a mountain bike and a 7 km run, also off-road.

Known by the nickname Mini Mac, Megan hails from Leamington Spa but lives in Loughborough, where she works as a part-time swimming teacher and trains with the Loughborough Development Squad.

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.”

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