Of blades and ski jets

A new cell, based on a robotically fed Makino machining centre configured for VIPER (very impressive performance extreme removal) grinding, has been installed at one of the Crewe production facilities of Trac Group. It follows the award of a long-term contract to produce four types of nickel alloy turbine vane for a leading European power generation company. Image: TRAC Group's VIPER machine supports production on a long term contract Supplier NCMT undertook turnkey responsibility for the supply of a Makino A99e machining centre and the process for producing the vanes. Included in the package were programs, grinding wheels, workpiece fixtures and a Fanuc M-900/A 6-axis robot for exchanging fixtured components automatically. The remainder of the production cell comprises two TEK4 deep hole EDM drilling machines, two die-sink EDM machines from Agie Charmilles and a Hexagon/DEA co-ordinate measuring machine. In 2004, Trac installed a smaller Makino A55 VIPER grinding machine to supplement conventional 5-axis CNC creep feed grinding on Blohm and Mägerle grinders. The A55 was deployed mainly on machining blades and vanes for power generation to cope with increased demand, but also on machining varieties used in aero engines. A year later, a similarly sized Makino iGrinder G5, purpose built from the ground up for VIPER grinding, was installed to meet a further increase in demand. It was the award in 2008 of a contract lasting well into the next decade to machine four varieties of larger vane for power generation that prompted investment in the new VIPER production cell. It was installed at the end of 2008 in a new satellite factory opposite Trac's main production facility in Crewe. Now in full production, it will grind a total of 186 engine sets of vanes during the life of the contract. Such has been the success of VIPER grinding at Crewe that Trac is constantly migrating its existing blade and vane work across from conventional grinders to the Makino machines. Makino VIPER grinding is also the automatic choice for new work won. Another company prompted to invest following a major order is Ellis Patents, Rillington, Malton. The company secured a major order to supply its new high voltage Centaur cleats for a large cable infrastructure project in the North of England. EXTRA DEMAND PROMPTS ACTION The solution to the extra demand was £70,000 Hurco VMX50m vertical machining centre. The 8.7 tonne, 40 taper, 10,000 rpm machine automates what was previously a largely manual manufacturing process, cutting the time to produce the aluminium cleats from 12 to three minutes per piece. Image: Automating what was once manual at Ellis Patents "When we launched the Centaur cleat in 2008, we anticipated a need to upgrade our machinery to cut production time, should a sufficiently large order come in," explains Richard Shaw, managing director, Ellis Patents. "We therefore had looked into the options available and budgeted accordingly. In fact, the only thing we did not anticipate was just how quickly we would need a machining centre." The Centaur range of heavy-duty extruded aluminium saddle cleats was developed by Ellis Patents in 2008 to restrain high voltage cables up to 400 kV with a diameter range of 100 to 160 mm. It fills a gap in the market that the company felt presented serious safety risks. "What spurred us on to develop the Centaur cleat was that most projects involving cleating large high voltage cables were designed on a case by case basis," explained Mr Shaw. "As a result, there were a very limited number of suitable products available and no published data to say that any of them have been short circuit tested." "What this meant was that specifiers were left to rely on manufacturers' warranties, which are based purely on calculations and mechanical tests, and there was no way of knowing if the cleats being used would be able to withstand the most demanding elements of the job for which they had been bought." Ellis Patents rectified this by putting its Centaur cleat through rigorous tests. Using cable manufactured by ABB in Sweden, the company shipped its Centaur saddle cleats to the Netherlands, where the product was tested to 163 kA peak and 63 kA RMS for one second, in both three-phase and phase-to-phase fault scenarios. The installed Hurco machine features Hurco's proprietary WinMax control, has a 21 kW spindle power and 1,270 by 660 by 610 mm capacity. The production set-up includes a Nikken CNC260 4th axis and MicroLoc fixturing system (Micron Workholding) to reduce the number of set-ups for each component. Moving onto a niche area of machining, that of parts for jet skis, and machinig centres from XYZ machine Tools, which feature the control, are helping out Chris Giles' firm, Air Time CNC. Air Time CNC is located just 10 minutes away from Queenford Lakes in Oxfordshire. This is where the company's after-market components, designed specifically for the freestyle specialist and marketed under the Air Time Products (ATP) brand name, are put through their paces, and from where leading professional riders have gone on to win UK and world titles on ATP-prepared and sponsored jet skis. MINI MILL IS FIRST CNC Although the initial idea was that Air Time CNC would design and develop its own product range and then outsource production, Mr Giles did begin making composite GRP and carbon fibre parts, progressing to the machining of aluminium and stainless steel components after experiencing quality control and late delivery problems with existing suppliers. "It was as a result of these problems, and with only a hazy idea of what it would involve, that I 'Googled' CNC and found XYZ Machine Tools," he says. "Lisa [his jet skiing wife] and I then visited the nearest XYZ showroom at Nuneaton, where we looked at a Mini Mill compact vertical machining centre, asked the relevant questions and listened carefully to the advice given." Image: Air Time CNC parts made with the help of an XYZ Mini Mill The machine came with a two-day training course, tooling package and a 3-year warranty. "Having decided to go ahead with this investment it was then on to a crash course in engineering," explains Lisa Giles. "We had to learn about every aspect of the machining process, from the materials and material grades needed for our range of products, which includes complete engine builds, through to programming and operating CNC machines." Air Time CNC's expertise now sees it offer a sub-contract design and machining service, based on CADCAM software from IndieCAM. This expertise has been acquired through necessity, as Mr Giles had no drawings of the parts that previously were outsourced, so he re-engineered every component, via CADCAM, and machined new prototypes for development and testing prior to production. First published in Machinery, January 2010