Fine detail requires only the finest technology for toolmaker Oromet

Oromet, part of the Optima Group, is the largest supplier of jewellery to the High Street. Formed in January 1994 the company has now established itself as a specialist toolmaker, taking in-house the work the parent company had subcontracted out since its formation in 1984, and in doing so controlling the design to production process.

"Long lead times are now a thing of the past," says Toolroom Manager, Neil Thompson. "Our first customer was our parent company, but the continuing investment in the toolroom means we now have the capacity to take on work from other sources. We have literally built the operation step-by-step from a CAD base, selecting the available production technology carefully," he added.

Available technology and careful financial planning saw Birmingham-based Oromet purchase a second hand miller, surface grinder, lathe and drill in its first year of operation. A second hand Agie 315 wire eroder followed in the second year, bringing in-house the subcontracted wire operation, but Thompson always knew the route he wanted to take once the toolroom was profitable. However, a lack of experienced toolmakers able to operate the latest required technology, caused the company problems.

Thompson explains. "It took some time for us to find the right toolmaking expertise and with both supplier and in-house training, now have a highly skilled workforce of twenty, and the technology to match. We found the Agie too slow and it was replaced in December 1997 with a Charmilles Technologies Robofil 290 with automatic wire feed. The Robofil 290 was initially purchased to make the small progression tooling, but with automatic wire feed the capability of the machine has seen us take on subcontract work."

In May ’98, the next technology step for Oromet was the purchase of a 3-axis CNC Lang Impala engraver/milling centre from HK Technologies and a Renishaw Cyclone 3D scanning system. "We were getting inconsistencies in our engraving work on our Triax CNC mills and after tests and other jewellers’ recommendations opted for the Impala," states Thompson. "It was principally purchased to machine the fine detail we would capture from the Renishaw Cyclone system. The TRACECUT scanning software, which is an integral part of the Cyclone system, allows us to automatically produce the NC part programs to carry out high speed detailed engraving work using a pointed D cutter."

Thompson continues. "We had been capturing detail from a scanned image or by taking 2D work from PEPS into an Artcam 3D package and attempting to ‘build up’ on the screen. This route took ‘days and days’, whereas with the Renishaw Cyclone machine we can have a model made in a scale of 5 to 1 and scan directly into the CAD/CAM system, making any alteration from known data if required, and DNC linking directly to the Impala. What used to take days can now be completed in a matter of hours."

"The jewellery business is very reliant on new designs," adds Thompson. "Customers can want to see samples in a matter of days. The Renishaw Cyclone system now gives us the facility to meet those time frames with alterations being made in minutes on screen. We can also capture very fine detail - we would rarely use anything larger than a 1mm stylus - from actual pieces, such as historical religious artefacts, e.g. Celtic designs." The system’s SP620 scanning probe is specifically developed for fine detail and delicate work. On all Renishaw ‘SP’ range probes, the stylus deflection and hence contact pressure can be chosen to suit the particular model being scanned. In the case of the SP620, this can vary from as low as 20gms up to a maximum of 80gms.

The Cyclone system’s very low contact pressure means that extremely small styli can be used without fear of damaging the article being scanned. At Oromet, ruby ball styli as small as 0.3mm diameter and pointed styli with a 0.1mm tip radius are used. This virtually eliminates any problems associated with sharp internal corners, often used as a criticism of contact probe systems. The stepover between scan strips is defined by the user and can be set to any value from several millimetres down to 0.005mm.

"We are even scanning in detail from old dies and clipping tools, which were created by hand, meaning no data exists. The Renishaw Cyclone machine gives us such a vast scope. We are thinking of new ways of using the technology every day," concludes Thompson.

Today High Street pressures result in Oromet being required to make samples more frequently, and resultant orders can require a suite of tools to be turned round in six weeks. A typical first run would see the production of 10,000 pieces with follow up runs of 35,000 to 100,000. For Oromet the right technology will always be critical as pressure from the High Street increases.