>COST-EFFECTIVE MACHINING Programming ease


The fact that Kevin Locke prefers to be out on the shopfloor rather than sitting in an office doesn’t mean that CJ Engineering is lacking either strong leadership or a sound business plan. It was back in 1998 that, in partnership with younger brother Nigel and colleague Ryan Mower, Mr Locke took on the running of the Thetford, Norfolk- based subcontract business, where he had spent the previous seven years working as a machinist. Two years later, with the business back on a sound financial footing, the decision was made to invest in a CNC/manual mill. This was to be the first of several CNC machine tools supplied by XYZ Machine Tools and it was to have a significant impact on the future direction of the company. The most recent capital investment is the XYZ ProTURN SLX 425 1.25m between centres CNC/manual lathe installed in May this year. The new 7.5kW/25-2,500rpm gap bed lathe has a 480mm swing over bed/700mm swing in gap and features constant surface speed (CSS) as standard. Reflecting advances in microchip technology and use of the Windows XP operating system, the latest generation ProtoTRAK SLX control is even more intuitive to use than before, with ‘plain English’ prompts contributing to significantly


reduced set-up times in one-off and low volume applications. “Our turnover has continued to grow as a direct consequence of moving to CNC machining, as these machine tools are much more productive,” says Mr Locke “The conversational aspect has enabled me and everyone here to get up to speed very quickly, and this means we can respond quickly to urgent requests. As a team we always do our best to help our customers and, in return, word of mouth


recommendations help to keep us busy, even in these difficult times.”


CJ Engineering has gained a reputation for its willingness to tackle challenging work, especially those involving the precision machining of hard materials. Reflecting its location in one of the UK’s major agricultural areas, the company has extensive experience of machining replacement parts for agricultural machinery in abrasion resistant Hardox. This is a martensitic steel available from its Swedish producer in several hardness levels up to 600HB and ideally suited for use in heavy-duty equipment such as hedge cutters and shredders subject to heavy abrasion. Demand from the agricultural sector tends to be seasonal, but CJ Engineering applies its knowledge of difficult to machine materials such as Hastelloy and Inconel to the precision


machining of aerospace related components and other equally demanding applications. It also tackles less demanding challenges involving the milling and turning of aluminium, mild and stainless steels, and plastics. With plenty of


competition for this type of work, Mr Locke emphasises the need to not overprice the job and to look to more efficient production methods as the way to stay profitable. “We regarded that first CNC machine purchase as a huge gamble at the time as we could have bought two or three manual machines for the same money,” he explains. “However, it was the right decision because it has allowed the company to grow and become more productive without the pressure of needing to find and recruit additional skilled people. By opting for CNC machines we have also been able to take on more complex work – the type of work that we could never compete for with purely manual machines.” CJ Engineering currently has eleven XYZ machine tools, including two vertical machining centres equipped with Siemens ShopMill conversational CNCs. These controls, like ProtoTRAK, can be programmed easily without any specific


programming coding knowledge being required, which is one of the reasons why CNC


programming at CJ Engineering is carried out at the machine


Economic investment


The fourth and fifth axes are provided by a 360° rotary table carried on a vertically mounted unit that swivels from -5° to 110° enabling undercuts up to 20° to be machined.


The only penalty is slower axis speeds – down from Evo’s linear motor driven X: 70m/minute, Y/Z: 50m/minute to


24m/minute in all axes. Even so, the DMU50 with simultaneous table is still a dynamic machine, with 5m/s² acceleration.


Value for money is the strong point of DMG’s new, vertical spindle, fully interpolative 5-axis machining centre, the DMU50 with simultaneous table.


The price is two thirds that of the German manufacturer’s high end DMU50 Evo 5-axis model, used worldwide for the high precision manufacture of complex components typically in the medical, motorsport and aerospace sectors. According to the manufacturer, the DMU50 with simultaneous table is around


three quarters the price of similarly specified models on the market from other suppliers. A further benefit of the machine is its 15% smaller footprint compared with the Evo. Build quality is comparable, so are the X, Y, Z travels of 500mm/450mm/400mm and the capability of the ERGOline control is equivalent. So full 5- axis technology at the ‘quality’ end of the market can now be accessed by a wider customer base across the general engineering sector.


It has a robust cast iron construction with generous webbing and ribs in all main parts. A thermo-symmetrical construction ensures high rigidity and torsional strength, thermal stability and guideway accuracy. A notable feature is the wide distance between the guideways. No special foundations are required for installation. Recirculating ballscrews in the linear axes transmit the feed force via robust bearings and components. DMG’s wide linear roller guideways feature low heat production, low friction, no stick slip and low wear. Linear


scales are available as an option to rotary encoders for positional feedback.


Digital AC drives are fitted for high dynamics and minimal maintenance and rapid response times between the drives and the control ensure high acceleration and accuracy, resulting in good surface quality and contouring accuracy. The central


lubrication system for the roller guideways and the recirculating ballscrews is based on minimal lubrication supply.


The 9/13kW (100/40% DC) motor spindle is driven up to 10,000rpm directly by a digitally controlled, three phase motor. It is equipped with precision bearings that are permanently greased, which together with the robust construction results in high cutting performance. Tool magazine capacity is either 15 (standard), 30 or 60 pockets. Alternative spindles may be specified – either 14,000rpm or 18,000rpm, the latter rated at 25/35kW (100/40% DC) with a torque up to 130Nm. There is easy access to the machining area and good chip disposal is ensured by steeply slanted walls with a side access door available as an option. A further option is the ERGOline control with 3D


To register for your free copy of Production Engineering Solutions, please go to www.pesmag.co.uk Production Engineering Solutions • August 2010 15


software on Siemens 840D solutionline, Heidenhain iTNC 530 or Heidenhain MillPlus iT platforms. Automation equipment and multi-pallet


systems are also available for unmanned operation.


>DMG www.dmguk.com


CJ Engineering’s Kevin Locke (left) says the decision to invest in a new XYZ ProTURN SLX 425 CNC/manual lathe was based on ‘machine performance and really good service and support’.


rather than offline. “Even if I could justify employing a full-time CNC programmer I prefer not to,” says Mr Kevin Locke, “as all the machining knowledge we need is out there on the shopfloor. If all that was required of people here was simply to run a CNC


machine, life would be pretty boring. I wouldn’t want to do that and I don’t expect others to do it either. As it happens, ease of programming is one of the many things we like about XYZ machines, and switching between ProtoTRAK and Siemens does not present any


problems as both systems can be programmed without using G and M codes.”


>XYZ MACHINE


TOOLS www.xyzmachinetools.com


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