Machining centres - Centre(s) of attraction

A shop adorned with machine tools from a single supplier is a good indication of a satisfied customer. In 2005, Midland Aerospace, of Sutton-in-Ashfield, acquired its first 5-axis machining centre from DMG (01582 570661), a DMU 70 eVo: today, the company operates six machines from the same supplier. And yet two of the latest DMG machining centres, installed in July 2011, highlight that not all of the subcontractor's business is in the aerospace sector. The DMU 50s were bought to maintain quick turnaround of an increasing amount of work from the motorsport and the energy sectors, both traditional and renewable. "We stayed with DMG as a supplier, because the first machine has been very reliable and so has the service," says Eamon Lyons, managing director. "Moreover, DMG offers a large range of high-end, 5-axis machines, so we know that each time we can source a model that exactly suits our needs." Image: Midland Aerospace has found DMG machines to be worth sticking with FORMULA APPROACH The formula of sticking with proven capability has also been successful recently for precision subcontractor Gretone Engineering of Lytham St Annes. When the company won an important new contract to supply 100 machined cast iron housings a week to very close size, position, flatness and surface finish tolerances, it was clear the company needed a high quality machining centre. The company already had a Toyoda FH60 horizontal machining centre, installed in 1989, and so this was where the company turned first. "Even with 21 years of constant service, the Toyoda's production capability and achieved quality levels have never been questioned," says Ian Hawkins, managing director. "While we looked at and dismissed other machines, it was obvious that this was the level of machine quality we needed for parts of this type." Gretone contacted UK agent 2D CNC Machinery (0844 871 8584), which resulted in the installation of a Toyoda FH630SX four-axis horizontal spindle machine with twin pallets. In order to meet the quality requirements, the stability of the machine and its ability to perform in a consistent manner over extended production periods was the key purchase factor: in particular, the use of dual ballscrews mounted on the Y and Z axes, linear scales and Toyoda's low friction roller bearing-based linear guideways that provide twice the rigidity and three times the vibration damping of traditional ball bearings. All faces of the machined cast iron housings must be square and flat within 15 micron and certain key features have positional tolerances within 12 micron. Since a management buy-out in 2010, Gretone has expanded from a previous £3.4 million to £4.8 million turnover and is well on target to hit £6 million this financial year. With 40% of its output delivered to the aerospace industry, the original workforce of 61 has been progressively expanded to 69. Another subcontractor with a vested interest in the aerospace sector is Southampton-based Benham Manufacturing, and, again, a trusted machine tool supplier is at the heart of the company's success. Benham acquired its first Mazak (01905 755755) machine in 1989, a Quick Turn 15, which is still running. This was quickly followed by a vertical mill. Benham acquired its first Integrex machine in 2001 and its first 5-axis model in 2003. The company now boasts 16 Mazak machines, including six Variaxis 5-axis machining centres and six Integrex machines for both milling and turning operations. Benham's most recent purchase is a Mazak Nexus 6000-II, the company's first move into horizontal machining. Managing director Paul Benham points to Mazak's ability to offer significant process improvements as the prime reason behind his loyalty to the company. "The speed of setting and machine control offered by technologies such as the tool eye, combined with rapid axis movements, has given us the ability to maintain our competitive position in the marketplace," says Mr Benham. "We ensure that our capabilities and investments match what the sector wants. Aerospace is very demanding for suppliers. Everything we do is detailed machining, typically to tolerances of 5 micron. "You must never stop investing," he adds. "You've got to spend the money to see the gain. Our business plan is allowing us to go from £7 to £10 million by end of 2014, with growth in both aerospace and new sectors." Another sector commanding a significant proportion of recent machining centre sales is the medical industry, particularly in Ireland. For example, Galway-based subcontract medical parts specialist Dawnlough has bought equipment to the value of £1.5 million since 2005, including eight vertical machining centres from Hurco (01494 442222). All of its business is in the production of special-purpose jigs and fixtures to assist in the manufacture of catheters, stents and other items for treating vascular and neurovascular disorders. According to managing director Brian McKeon, programming demonstrations performed in 2005, using a dummy Hurco Max control, showed that big savings were possible. The exercise was directly responsible for Dawnlough's purchase of the first Hurco machining centre, a VM3. It was joined two years later by a similar model, followed by a line of three smaller capacity VM1s in 2009 and three of the updated VM10 version in 2010 and 2011. Of the eight Hurco VMCs currently on the shopfloor, three are fitted with an integrated Hurco H200 rotary table to provide a fourth CNC axis that can also be programmed conversationally, directly at the control. "Production here is mainly one-offs and small batches, so we wanted to be able to program each new part quickly on the shopfloor, otherwise job preparation becomes too large a proportion of overall manufacturing time, reducing profitability," says Mr McKeon. Image: The Hurco control is a big time saver for Dawnlough HALF THE TIME Of course, sometimes there's good reason to switch machine tool supplier, as Crediton-based Adaero Precision Components discovered recently. The company's main business is in the medical and ophthalmic industry, which accounts for 40% of turnover. When an aluminium billet was put on a new Brother TC-22B-O vertical machining centre from Whitehouse Machine Tools (01926 852725) shortly after it arrived last summer, the finished component came off in 13 minutes. Previously, it took more than twice as long (28 minutes) on one of the subcontractor's older machining centres, which are now systematically being replaced. The Brother's ability to take so much time out of the cycle was also down to minimising non-cutting time. Rapid traverse of 70 m/min in all linear axes contribute significantly in this respect, and so, too, does the automatic tool change time: 900 milliseconds tool-to-tool including spindle acceleration and deceleration. In January 2011, another vertical machining centre from Brother was installed at Adaero, this time a 4-axis model with twin automatic pallet change. Designated TC-32BN QT (quick table), the machine joins several rotary pallet machines on the shop floor, as well as a long-bed machining centre used for pendulum machining. "We are so busy now that all our machines, including the Brothers, are close to capacity. As a result, we have decided to put on a second shift from 17:00 to 02:00 to supplement our 08:00 to 17:00 day shift," says managing director, Andy Dickinson. Image: Brother machines are a success at Adaero It goes without saying that all subcontract machine shops have to start somewhere and the story of Leeds-based Cannon Engineering is probably common to many. Chris Hannam initially built an 800 ft2 workshop in his back yard, installing manual machine tools and spending the next year working seven days a week. His hard work paid off, because, several years later, in 2002, Cannon Engineering began investing in CNC/manual and full-CNC machines from XYZ Machine Tools (01823 674200). Two years later, he bought his current 4000 sq ft premises and the plant list now includes two XYZ Mini Mill vertical machining centres, a ProtoTRAK bed mill, and a ProtoTRAK turret mill, among other models. As well as being a time-served gear cutter who runs his own subcontract engineering company, Mr Hannam is also an accomplished motorcycle drag racer, who not so long ago set a world record for the fastest-ever 'wheelie' (168 mph on a turbocharged Suzuki Bandit). The parts produced by Cannon, however, are for a range of industries, not just motorsport. Soon to be added to the plant list will be one of the first XYZ ProtoTRAK LPM machining systems to be installed in the UK – the first ProtoTRAK-equipped machine to be fitted with an automatic toolchanger. This new 'Lean Production Machine' will allow the operator to both program and set up the next job while the machine is running. "I've put my faith in XYZ because I like the products, I like the people and I like the back-up they provide," says Mr Hannam, a sentiment shared by many in reference to their respective machine tool partners, it seems. Image: Cannon Engineering likes XYZ products and people Box item The wraps are off Among the latest market entrants, Mills CNC (01926 736736) is launching Doosan's range of best-selling DNM vertical machining centres into the market. Both the DNM 750 and the DNM 750L are equipped with Doosan Fanuc controls, 12,000 rpm spindles (BT 40 Big Plus) and 30/40-position ATCs. Mills is also releasing to the UK the DNM 350 5AX (classed as an entry-level machine) – the second Doosan 5-axis machine tool range launched by Mills in the past 18 months. Continuing the 5-axis theme, German machine tool manufacturer Hermle has added the C 60 U to the upper end of its range of 5-axis vertical machining centres, with availability through Geo Kingsbury Machine Tools (023 9258 0371). The C 60 U is intended for 5-axis machining of components weighing up to 2.5 tonnes. Some new releases are pitched at specific challenges, and the new Makino T2 5/6-axis horizontal machining centre is no exception. Titanium machining for sectors such as aerospace and motorsport are where supplier NCMT (020 8398 4277) sees its best chances of success, as it is able to hog Ti-6Al-4V at up to 500 m3/min. There are plenty of new innovations when it comes to 3-axis machining centres too. Mori Seiki (0844 800 7647), for example, has started taking orders for No. 50 taper spindle specifications for the NVX5000 Series of vertical machining centres. These machines are able to achieve thermal displacement of 7 micron or less, in response to an 8°C change in ambient temperature. Finally, Birkett Cutmaster (01274 870311) has launched a twin-head milling machine, claimed to operate much faster than conventional vertical machining centres. When milling four sides of a workpiece, conventional systems machine all four surfaces one-by-one. By contrast, the Amada THV milling machine operates with two cutters to machine two sides of the workpiece in a single operation. Image: A twin-headed milling machine is faster, says Amada First published in Machinery, October 2011