Turned to perfection

4 min read

Investment in a large capacity CNC lathe with powerful driven tools is helping one aerospace company, while sliding-head technology has boosted the fortunes of two subcontractors, as Andrew Allcock reports

(Video shows Star ST-38 sliding head mill-turn - see later) Kigass Aero Components is using its recently installed Doosan Puma 480M lathe (Mills CNC, 01926 736736) to make high precision, complex parts for a leading UK aero-engine OEM. The benefits have been reductions in both set-up and cycle times, with higher work throughput resulting. Production bottlenecks are less common and part accuracies, due to reduced work-handling or transfer between machines, are more easily achieved. Peter Platt, managing director, explains the reason for the investment: "Our existing turning technology for small diameter parts is more than adequate for our needs – but our turning capability for handling larger diameter parts (600 mm and above) needed attention. "However, we weren't just looking for a larger machine tool. Instead, we wanted to develop a new stable, reliable and repeatable manufacturing process to make these larger diameter parts to the accuracies, geometrical tolerances and surface finishes required. After discussions with different machine tool suppliers, we determined that the Doosan Puma 480M from Mills would be a central component in us achieving our objective." Prior to the new investment, parts were milled and turned on different machines. "Waiting for our milling machines to become free was creating a production bottleneck. And spending time and resources on job set-ups was also inefficient and costly," Mr Platt reports. "Originally, we thought that a mill-turn machine would be a good way of addressing the challenges we were facing and would allow us to produce parts in fewer set-ups. But, having discussed our ideas with Mills, it became apparent that the best and most effective solution (and the one that would give us most flexibility now and in the future) would be to invest in a large, high performance lathe with driven tools. So that's what we did." LARGE CAPACITY TURNING The Puma 480M supplied has a 21" chuck/165.5 mm bar capacity, a 45 kW (gearbox-driven) 1,500 rpm spindle, and a 12-station turret. The machine has driven tooling capability (11 kW/3,000 rpm), and was supplied with Seco's Jet Stream high pressure coolant system (01789 76434) and a tool-setting probe. Image: Heavy duty turning at Kigass Aero Components, supported by Doosan technology Concludes Mr Platt: "The Puma 480M has a Fanuc control – something we are more than familiar with and we already had good experience operating Puma multi-axis lathes. These factors, as well as the new machine's competitive price, it's availability and the fact that it's backed by Mills' after-sales and service support, made the decision to go with the Puma 480M an easy one to make." Moving to smaller parts and precision parts manufacturer Neida Blue 62, a combination of Blue 62 and Neida Products, continued its investment in the latest mill-turn technology, with the acquisition last year of a Star ST-38, 38 mm bar diameter sliding-head lathe. The Freshwater factory on the Isle of Wight has 24 CNC machine tools for turning and prismatic machining, including multi-axis sliding-head bar lathes spanning the capacity range 16, 20, 32 and now 38 mm. Neida's policy is to invest in the latest machine tool technology. It inherited its first two Star machines when it acquired Isle of Wight subcontractor Blue 62 in 2005, but subsequently added three 11-axis, twin-turret ECAS-32Ts, two of which were installed in 2011, and four SV-series sliders, all with extensive driven tooling and backworking capabilities. The 12-axis, triple-turret ST-38 takes sliding-head technology a stage further, in terms of productivity, however, according to Neida Blue 62's general manager, Simon Fisher. "The 38 mm capacity lathe obviously allows us to turn bigger diameter bars than on the other Stars. "However, the main reason for our investment in this machine revolves around its greater stability and the productivity gain, together with much quicker set-up times, which gives us greater flexibility and competitiveness within the market. "Compared with the 32 mm Star ECAS and SV models, which themselves are capable of impressive throughput, the ST-38 achieves even higher productivity." In fact, he puts the productivity advantage at up to 30%. "The advantage is greater than we thought it was going to be," Mr Fisher adds. "The latest Star sliding-head lathe technology amounts to a game-changing advance, not to mention the machine's bigger capacity, which takes it further into fixed-head territory." As it happens, due to its rigidity, the machine is mainly reserved for cutting 316 and 304 stainless steel components – the machine has been fitted with a high pressure coolant delivery system to support this, in fact. Image: Star ST-38 - a game-changer for Neida Blue 62 RAPID PROGRESS Sub-CNC has also progressed, initially using sliding-head technology, but has come a long way in just three years. This year, Citizen sliding-head turned components from the company will feature in one F1 team's car. Set up in April 2009, by Yian Stavrou, managing director, and George Dingley, technical director, the company started with a 20 mm bar Citizen L20 CNC sliding-head turn-mill centre, added a fixed-head, 44 mm capacity, two-axis chucking lathe, then a second, larger capacity sliding-head machine, a 32 mm bar Citizen L32 in the same year to meet the fast growing order book. In 2010, it installed its first new machine, a 20 mm bar Citizen A20-Vll and also relocated to larger premises in Dunstable, close to its original converted cowshed near to Luton. Demand for under 20 mm component size had rocketed, including its breaking into the F1 industry with a new contract, but the two engineers felt the Citizen A20 purchase and factory move meant there was a breathing space to re-align the business for the future. Explains Mr Dingley: "Existing customers were not only adding to our order book, but were beginning to make it very clear that they wanted Sub-CNC to supply larger diameter bar components as complete packages, rather than have to deal with 'cherry-pickers' who could or were only willing to perform certain tasks." At the close of the year, the company ordered a BNA-42MSY, a six-axis fixed-head turning centre, following an Open House event held by Citizen Machinery (01923 691500). This was the first Miyano to feature the so-called Streamline CNC technology employed by Citizen sliding-head machines, which, in addition to speed, provides a consistency of programming familiarity to Sub-CNC. The company has continued to progress, employing an apprentice, investing in support technology and setting up production control/scheduling systems. Image: Sub-CNC - growing fast, investing and training for the future Box item Recent product launches in brief [] The Haas ST-10Y is a small-footprint Y-axis turning centre that provides 102 mm of Y-axis travel (±50.8 mm from the centreline) for off-centre milling, drilling and tapping, and comes standard with high torque live tooling and a servo-driven C axis for versatile 4-axis capability [] The Okuma LT2000-EX (NCMT), which can turn-mill chuck, bar and shaft parts, offers capacities of 200 mm diameter chucking, up to 65 mm bar work and 700 mm maximum shaft length [] The Gildemeister CTX beta 800 4A opens up 4-axis production turning for medium sized components up to 735 mm turning length and 300 mm diameter for chuck machining and up to 102 mm diameter for working through the spindle [] Available from Leader CNC Technologies is a range of FAT-Haco CNC and manual lathes in slantbed (FAT-Haco FCT/FTM) and flatbed CNC and manual ( TUR MN) formats First published in Machinery, June 2012