Solid Machinist slashes motor sport parts machine times

Producing components for racing cars is a challenging business. Rapid response, flexibility, seasonal demand and on-time delivery sit alongside the need for innovative design, new technology and ultra-high quality. Motor sport transmission firm Xtrac is right in this business. With a turnover last year of £32 million, the firm employs 180 people at its factory in Thatcham, and designs, manufacturers and assembles parts for two and four-wheel drive racing transmissions and the like. It also produces engine timing gears, drive shafts, rack and pinion assemblies and flywheels used in everything from Formula 1, to Champ cars and US IRL racing; as well as world championship rallying, touring cars, sports cars and even ice racing. It’s specialised work, and production of all this is handled by some 50 CNC machine tools – including nine lathes, 13 machine centres and five gear hobbers – with CAD/CAM software central to its operations. Xtrac is a long-term user of Unigraphics CAD software and Pathtrace’s EdgeCAM computer-aided manufacturing (CAM) software on the shop floor, using Unigraphics’ Parasolid export as the interface. It’s an effective combination. What’s most interesting now is that the firm says the latest EdgeCAM Solid Machinist release has enabled its engineers not only to streamline programming but also to dramatically improve machining efficiency. This latter applies particularly to several complex parts produced on its multi-axis CNC lathes and machining centres, following beta testing by production engineer Spencer Ford. Tony Buckle, Xtrac’s CAD/CAM manager takes up the story: “The ability of EdgeCAM Solid Machinist to directly import Parasolid data from our Unigraphics CAD system considerably speeded up our programming for complex 3-D components. It also solved a major problem by being able to import design data directly into the programming software. In the past, we were always concerned over losing feature details such as depth of cut or radii because we had to use IGES and DXF translators between CAD and CAM.” Next, he says several of the firm’s CNC lathes are turning centres using driven tooling, turning, milling and drilling several parts in a ‘one-hit’ cycle. The tools perform an intricate series of profile, circular, slot and face milling operations, as well as drilling, boring and tapping with tolerances of 10 micron. Here, EdgeCAM has been used to optimise many of the mill-turn programming routines; it’s also enabled complex sequential gearbox barrels to be programmed for production much more rapidly. In particular though, the software really shone when it came to handling Xtrac’s 3D surface milling. One component was a complex input drive gear housing for a motor racing constructor. Using EdgeCAM Ford was first able to cut programming time of a high speed, five-axis vertical machining centre by 20%. Then three machining operations – involving fine detail work and external profile milling – were ultimately merged, and machine cycle times reduced by a third as the programming was improved. Buckle sums up the main benefits as Solid Machinist’s ability to import Parasolid-based files, and the power of its pencil milling and automatic feature recognition (AFR). “EdgeCAM AFR automatically identifies whatever features you specify on the screen solid model and groups them together, which allows us to optimise machining cycles and tool changes.” According to milling shop foreman Kim Horton, who had the task of producing most of the CNC programs for the housing, EdgeCAM’s pencil milling “has cut our machining cycles by some 15% on external fine detail type work.” And he adds: “Pencil milling has enabled us to reduce the number of separate machining operations from eight to five on the stepped edge faces, radius forms and lower flange profile of the angle housings. This alone has reduced machining time by several hours per part.”