Rimor gets 'DEPOCAM' to handle 'IGES' files

Rimor, which employs more than 100 people in its 35,000sq.ft factory in Hampshire, has a plant list including eight Bridgeport machining centres, a Mazak machining centre, an Acramatic 'Eagle', driven tooling lathes, two Tos machining centres and a Sachman five-axis machining centre. It operates a night shift, and can run on a 24/7 basis with certain machines running unmanned in the evenings and at weekends.

The motorsport work carried out on these machines includes bespoke engine components, such as cam covers and fuel-line components, mainly in aluminium and machined from solid. Typical features include complex pockets and webs to produce a very light yet structurally sound component. For motorsport gearboxes, the company produces selector forks, transmission shafts and gear blanks, which require milling operations to cut lightening holes, as well as turning operations. Titanium suspension components are tougher to machine, requiring careful selection of tooling, feeds and speeds and cutting techniques.

"Titanium is a difficult material to cut," said Rimor's Ray Oakley. "We machine from a solid block supplied by the customer, and in some cases it is necessary to cut deep pockets with small tools. We find that the correct tooling geometry makes a lot of difference on titanium."

Rimor uses area clearance, waterline, raster and constant stepover routines in 'DEPOCAM' for titanium, and gets improved cutter life by machining the walls first and adjusting the angles to be cut, to avoid hitting the side of the job. For deep pockets in titanium, Rimor uses a sequence, starting off with large tooling and progressively working down to depth with smaller and longer tools. "We frequently cut pockets which are 60mm deep and we use tools down to 2mm diameter," added Oakley. "Combining the machining routines available in 'DEPOCAM' produces a very smooth surface finish at the transition between the different tools we are using." The ability reliably to avoid ploughing into unmachined material, and to take very small cuts, is vital for tool life and finish. Furthermore, with customer-supplied material, very short production runs and lengthy cycle times, errors in machining can be very costly.

Rimor also wanted to use high-speed techniques on its conventional machine tools within the limits of the feeds and speeds available on each machine. A combination of improvements to the postprocessed code and smoother toolpaths generated by 'DEPOCAM' now makes it possible to run at much higher feedrates without the jerky movement of the machine, which had previously been experienced by Rimor. Smoothing algorithms inside DEPOCAM ensure that there are no sudden direction changes in the NC code, so that the machine tool does not need to accelerate or decelerate unnecessarily, while even stepovers and smooth corner transitions ensure that the tool load is constant.