Turning treats

7 min read

Installing latest turning technology is cutting cycle and lead times, as well as boosting quality at a number of companies, as Machinery discovered

At its Daventry factory, Hi-Force has invested £850,000 with Mori Seiki (UK – 0870 240 9500), which has supplied a turnkey solution for the company, consisting of two NL3000 lathes with Y-axis, a Duraturn lathe and a NMV5000 DCG 5-axis machining centre. Image: XYZ machines supported the establishment of Faringdon Precision Engineering. Easy programming was key Hi-Force makes tools – used in the oil and gas, power generation, railway, construction and shipbuilding industries – designed to apply controlled loads and torques for leak-free flange connections and heavy jacking applications. Kevin Brown, managing director, says: "We made the decision to move the majority of our machining in-house, as we needed to achieve much better control of our manufacturing and offer our customers the benefits of increased flexibility and shorter delivery times." Hi-Force has 11 overseas offices, 100 distributors worldwide and exports 85 per cent of its output. Previously, the company had to rely on its UK and global sub-contractors; if one essential component was delayed, it would hold up the delivery of a finished tool. Similarly, if a rapid delivery were required, the company would frequently have to pay a premium for out-of-hours working. Explaining why the company chose Mori Seiki, Mr Brown offers: "Mori Seiki is known for quality. This is important to us and ensures that our customers understand our commitment to UK manufacturing. We also needed a total solution, including tooling, workholding, training and programming – a complete technology transfer programme to ensure the success of the project." COMBINED OPERATIONS The two NL3000 machines are used to manufacture a range of cylinders and, having Y-axis, they are able to combine several operations, so that a finished part comes off the machine. Metal removal rates are important, as around 70 per cent of the billet is machined away during cylinder manufacture. "Mori Seiki has been very helpful in optimising our processes. We did not realise how powerful the machine was and we are now taking depths of cut that are double those we had hoped for. The resulting shorter cycle times have produced at least 25 per cent more capacity than we anticipated, enabling us to bring even more work in-house." Hi-Force has also chosen Mori Seiki's maintenance programme, which provides a planned maintenance schedule and includes the cost of repairs. "The maintenance plan ensures that we have accurate and predictable knowledge of machine running costs," underlines Mr Brown. "We recently had a machine tool collision caused by human error and Mori Seiki engineers were here within four hours to start fixing the machine. Our experience is that the service from Mori Seiki is first class, and that problems are resolved in a controlled and professional manner." The majority of Hi-Force's products are delivered within seven days, as it holds a significant amount of stock. However, the new Mori Seiki machines have cut typical turnaround times from eight to four weeks. "The shorter manufacturing times give us considerably more flexibility," explains the managing director. "A condition of a recent major order was for delivery within two weeks. We were able to reschedule our production, thanks to the new machines, so that we could be sure of meeting the customer's demands." Shorter production cycles have also resulted in lower costs. "We are achieving savings of around 25 per cent in manufacturing. We are moving into a new purpose-built 50,000 ft2 facility in 2010 to meet our plans for growth and to continue our policy of 'Made in the UK'. We anticipate that, as part of this expansion, we will be investing a further £400,000 in Mori Seiki equipment and services." Moving to a smaller operation, Trevor Timpson and Gary Evans, co-owners of Oxfordshire-based Faringdon Precision Engineering, set out to produce high quality precision engineered components, using state-of-the-art CNC machine tools, CADCAM and inspection equipment on a 24/7 basis, whenever fast turnaround is required. EASY TO PROGRAM AND USE The two directors, with more than 40 years of engineering experience between them, had taken six months beforehand to plan and act upon a sub-contract machining business plan that would give them maximum flexibility, in terms of the work they could take on. "This is why we decided to install [XYZ] machine tools equipped with the Siemens ShopMill and ShopTurn conversational CNC systems," says Mr Timpson. "Programming with these systems is so quick and easy that we knew we could compete on one-off and prototype work against people using manual machines. We knew, too, that we could compete on batch work against people using CNC machines equipped with more complicated and time-consuming programming systems based on G and M codes." Amongst a range of machine tools purchased from XYZ Machine Tools (UK – 01823 674200) are three XYZ turning centres, the largest of which can machine components up to 250 mm diameter. In addition to the motorsport and aerospace industries, Faringdon Precision's remit extends to defence, oil and gas, railway, medical and semi-conductor work in a wide range of materials. "We can machine just about anything…Inconel, titanium, duplex stainless steels, glass-filled plastics…but part of our success is down to the fact that we are not afraid to ask," Mr Timpson says. "There's plenty of advice available from suppliers, such as XYZ, and I don't think there is any job that, aside from the physical limits of our machines, we couldn't do now. The XYZ machines are robust and fully guaranteed, and the service and support is very good – which is important, as delivery is the key to keeping our customers happy; this is particularly true of Formula One teams." Smaller components were the target at APPH Nottingham in a recent investment programme. Components made by the company are destined for the aerospace sector, particularly the landing gear that its parent group designs and manufactures. Many components are mill-turned from stainless steel and titanium bar, so, in June 2007, when the company was looking for its first sliding-headstock CNC turning centre, particular attention was paid to the robustness of the machines on offer. The decision was taken to buy a Star sliding-head lathe (UK – 01332 864455), owing to its rigidity and significantly heavier construction than other available machines. The model chosen was a 9-axis Star SV-32, which has an installed weight of 3.8 tonnes. The high power drive to the live cross-working and end-working tools was another factor in the decision. Bar up to 3.2 m long is fed into the working area by an FMB Turbo 3-36 magazine, and the machine has turret-mounted tooling, as well as a gang toolpost, and has been equipped with high-pressure coolant delivery for improved chip control and tool life when producing safety-critical components from exotic aerospace metals. The investment in the Star in 2007 was part of a major plant upgrade that also saw the installation of a Mazak Integrex turning centre (UK – 01905 755755) and, prior to that, three CNC Mill-Turns from WFL (UK – Kyal Machine Tools, 01780 765965). The SV-32 is used for one-hit mill-turning of parts up to 32 mm diameter, mainly stainless steel and high carbon steel plungers. Each is subsequently match-ground to fit the bore in the body of an hydraulic actuator. Another regular contract fulfilled by the SV-32 is the production of titanium alloy vortex tubes in batches of 2,000-off, 27 of which fit into a titanium ring that forms part of the fuel distribution system in an aircraft. Image: APPH says that the Star machines were heavier and more rigid were other makes The remainder of the sliding-head lathe's time is spent on mill-turning intricate sleeves, connectors and other components to tight tolerances. Formerly, such parts had to visit two, three or even four machines. In addition, a part number is engraved on some components, which is also performed in-cycle on the Star lathe, saving a further separate operation. FASTER, BETTER, COST-EFFECTIVE Benefits have included faster turnaround, better component accuracy by eliminating tolerance build-up, and lower costs through reduced operator involvement and less work-in-progress. "Irrespective of shape, complexity and material, provided that it is of 32 mm diameter or less, a component can usually be machined more efficiently on the Star sliding-headstock lathe," underlines APPH Nottingham's manufacturing engineer, Dave Fell. And, adds machine operator Dave Broadfoot, even though the company was new to sliding-head turning at the outset, on-site training for one week was sufficient to ensure proficiency in machine programming and operation, despite the nine controlled axes. Image: Citizen machine technology is supporting Triflow's top-of-the-range fittings business Staying with sliding-head technology, but moving to the manufacture of exclusive taps, water filtration systems and bathroom and kitchen accessories, and Triflow Concepts has ring-fenced its reputation by adopting a philosophy centred on quality – quality of product and quality of every sequence in its manufacturing chain. Not surprising, perhaps, when you know that its top-of-the-range, innovative brassware tap concepts sell for up to £7,000 a piece. According to Keith Liversage, plant manager at the company's Wolverhampton site: "Everything is manufactured in-house – including castings, full machining, finishing, plating and assembly – and we employ the same quality and performance ethos to everything, including all the production equipment we install." Directing his comments to two of the latest Citizen M32-V top-of-the-range CNC sliding head turn-mill centres (Citizen Machinery 01923 691500) installed mid-2008, Mr Liversage says the machines were selected on merit. "It was a basically simple decision after checking out competitor machines," he adds. Engineering manager Ajit Singh confirms from their experience to date: "We have programmed 53 parts over six months, and produced 98,000 components on one machine and 90,000 on the other," he says. "In achieving this, these two machines have replaced four, three-axis turn-mill centres that could never come near the cycle time, level of quality, and the speed of resetting and change-over that we are now obtaining." And he reports that the average cycle time for all the 53 parts has fallen from 2.33 minutes to just 0.66 mins, giving an average saving of 1.67 minutes per part. Fast delivery, plus reliable supply, are key for the company in this cost- competitive market. "The brassware market is ultra-competitive and we are fighting against a host of low-cost producers around the world, keen to copy or provide a standard product. Having selected Triflow taps, customers normally want the installation completed quickly, so we cannot afford stoppages in production," Mr Liversage says. FAST CHANGEOVERS He maintains the company must reduce stockholding, work in progress and move towards a make-to-order initiative, and this is where the Citizens are helping achieve the goal. An average changeover takes under 45 minutes. with these predicted to rapidly reduce by half in the future. Previously, the three-axis turn-mill centres took between two and four hours to reset. The Citizen machines also allow the company's designers to be more creative and to move it farther ahead of the competition. As for quality, Mr Singh says that batch sizes are between 50 and 2,000, and each machine is always set to mid-limit. "Once the first-off is approved, there has never been any requirement to adjust offsets, and, from the first to last part, our records show there have been no deviations." The machines are programmed and optimised offline using Citizen's UK-developed CNC Wizard. First published in Machinery June 2009