Another good turn

Flexibility to meet a wide variety of customer requirements is at the forefront of Inca Geometric's need in machine tools. So when it was considering the purchase of a new, large capacity lathe, it had to be a universal specification. However, topping the essentials of the shopping list of features and benefits were rigidity, a good control system interface and the ability to maintain a good surface finish on aluminium and plastics, as well as a wide range of steels. Inca Geometric, based at Chartham, near Canterbury, Kent, is a special-purpose machine tool and general engineering sub-contractor. So when it checked out the specifications for the type of universal lathe it needed, build quality, capability and support were carefully matched against value-for-money. "There was very little we could criticise in the Dugard Eagle 400 when compared to other machines available, and that includes certain machines that were considerably more expensive," recalls Inca Geometric works manager Tony Clifford. One of the reasons for build quality being very high on the agenda for Inca is a long-standing contract for precision turned components for a customer in aluminium, brass and perspex that can be up to 550 mm in diameter. Produced in batches of up to 50 a month, the company faces strict quality requirements for the 'as turned' surface finish, with added geometric demands for concentricity, flatness and parallelism. The heavy duty, 9.5 tonne Dugard Eagle 400 was installed in May 2008, and such was the capability of the machine and the support from C Dugard that in August a pre-owned Quaser vertical machining centre with fourth axis and Heidenhain control was installed for further general machining tasks. Some 18 months before the installation of the lathe, Inca also took delivery of a large TOS W100A horizontal boring machine from C Dugard with Heidenhain 5-axis readout to control the 49 inch square indexing table and extending quill movements in addition to X, Y and Z. Adds Mr Clifford: "We look at any equipment supplier from a machine tool perspective and the support from Dugard on all three machines has been first class. The installations were very straightforward, due to the competence of the crew that had the experience for any eventuality." LARGE SHAFT CHALLENGE The Eagle 400 lathe has supported a number of tasks at the company. The company recently had to pick up a large shaft from a power station at midnight, reverse engineer a new part, machine it on the lathe and have it back to the station by 6 am the following morning, ready for its reassembly. "This is where a flexible, universal machine and the Fanuc control pays dividends," says the works manager. Another example is the machining of an aluminium wheel-style component from billets around 555 mm diameter by 41.5 mm thick. Originally they were cast, but blow holes were a common problem. In recommending the switch of raw material to a blank, Inca redesigned the component with its central boss as a separate item to save material that is then machined separately, leaving stock material for finish turning. The boss is then screwed and secured with Loctite into the bore of the main wheel and finish turned as an assembly, with the addition of a screw-cut thread on the OD. Says Ann Cain, managing director: "We are still very much a family business that has kept its skill base and, as such, we can turn our hands to almost anything. This is why we need such high levels of flexibility with any machine we install. Our biggest problem is finding the skill levels to tackle one-off jobs, so we are always keen to train apprentices and, in fact, one who joined us when he was 16 is still here at 67." For Yorkshire Precision Engineering (YPEL), the ability to produce complex components in one set-up sets it apart from its competitors. This edge over rivals has seen investment in new machine tools and an adjacent unit that saw YPEL increase its manufacturing area by 50 per cent in February this year. Turning, milling and drilling intricate parts on one machine without the need for secondary operations has always guaranteed the success of the business as the benefits of improved cycle times, accuracy and quality all come into play. Until recently, the ability of its turning centres to machine parts from 0.5 mm to 32 mm diameter was sufficient. However, the continually changing marketplace has seen an influx of work outside the 32 mm parameters of its sliding-head machines. It was this injection of new work that led the company to invest in a larger machine. As a facility that runs 24/7, Yorkshire Precision machines batches from 25 to 100,000 in anything from aluminium, PTFE, brass and copper, through to carbon steel, mild and stainless steels and titanium. With a diverse workload, the company demanded a machine equally capable of meeting the standards set by the sliding-head lathes – so a Miyano BNJ 42SY with 42 mm diameter capacity was installed in October 2008. The twin, opposed spindle Miyano BNJ 42SY has two turrets, each with 12 stations and Y-axis capability, and has been able to reduce cycle times by an average of 35 per cent – something that has been noted at BTMA member YPEL. The transition for operators from the sliding-head lathes to the Miyano BNJ 42SY was easy for YPEL as the Miyano and Star machines employ the same Fanuc 18iTB control. Miyano's standard 5-day training programme was cut to just one day, with operators immediately at ease with the fixed-head turning centre. From a production standpoint, the Miyano made an immediate impact with a number of jobs transferred from the current machines. A large percentage of jobs had a considerable amount of milling work and the sliding-head turning centres are designed primarily for production turning. The larger, more robust Miyano enabled YPEL to double the previous feed rates and depths of cut. On one particular mild steel hydraulic connector, the cycle time has been cut from 7 mins 20 secs to just below 5 mins. Regularly produced in batches of 1,500 to 2,000, this 40 per cent reduction in cycle time is an astounding result. Director Michael Laybourne says: "Before the Miyano arrived, we were sub-contracting the larger work out to machine shops with large diameter capacity. However, our suppliers were passing the increasing material costs on and we were forced to pass this on to disgruntled customers. The Miyano has allowed us to bring the work in-house and produce it 20 per cent faster. This has enabled us to absorb the material cost, reduce the customer's cost and strengthen our relationship with a good client into the bargain. STAYING PROFITABLE "Our aim is to maintain our profitability in the midst of an economic climate that continually sees material and energy costs increasing. To maintain our margins without passing the costs to the customer, we have to do jobs faster, so we can absorb the costs. The Miyano has certainly enabled us to achieve this and, in turn, we can pass the benefits to our customers. As the company moves forward, we will be looking to increase the workload of the Miyano and we will actively promote its capabilities to our customers," concludes Mr Laybourne. For 60-employee Alken Engineering, an urgent enquiry for the machining of 3 m long En9 shaft components convinced Paul Coverley, managing director, it was time to translate his intention of buying a larger capacity CNC turning machine into immediate action. The downside for the Thornsett Trading Estate in High Peak, Derbyshire, firm was that the machine tool suppliers he contacted quoted deliveries of up to six months, while the potential customer was talking in terms of weeks, and the prices being asked for turning centres would make his quote uncompetitive. Although an existing user of manual/CNC lathes and turret mills supplied by XYZ Machine Tools, Mr Coverley says he was not aware that the Burlescombe, Devon, company could satisfy his capacity and delivery requirements with a less expensive alternative – until he was given a demonstration of the XYZ ProTURN SLX 555 manual/CNC lathe. The outcome was the installation in July 2007 of a 3 m between centres version of this 11 kW (15 hp)/30-1800 rpm gap bed lathe, and the winning of a seven-year contract for the machining of locomotive axles. Standard equipment supplied included a 300 mm diameter three-jaw chuck, quick-change toolpost with six holders, air-assisted 'floating' tailstock, interlocked chuck and main guards, and joystick control for rapid movement. A latest-generation ProtoTRAK SLX control contributes constant surface speed, tool tip radius compensation and a host of other features, while its 'traking' feature ensures the end user is always in control, allowing operators to check the programmed toolpath before switching to computer control. Alken Engineering's new ProTURN SLX 555 is currently double-shifted, and has shown it will be as reliable and efficient as the other XYZ machine tools on site. "Once someone buys their first XYZ machine, it won't be long before they buy another one," advises Mr Coverley. "These machines perform well, command good residual values, and our experience is that they definitely improve the standard and quality of our work."