BLADE RUNNER

You're Olympic bobsled champions, but how do you transfer the proven speed of hand-made blades into a new standardized material mandated by the sport's governing body?

The blade project arose following new rules introduced by the FIBT (International Federation of Bobsleigh and Tobogganing) in October 2006. The new rules aimed to remove on-going disputes over the use of various materials and treatments in blade manufacture. All bobsled teams must now use the same specification steel with creativity allowed only in blade form.

Sandra Kiriasis prized the competitive edge achieved by her existing blades, but as these had been created using manual techniques, there were no drawings or electronic CAD data to allow them to be re-manufactured using the new standard specification steel. An appeal in a German metalworking magazine by Team Kiriasis, the world's top two-person woman's bobsled team, brought a partnership proposal from world manufacturing leaders Renishaw, Siemens, Sescoi and Iscar.

Renishaw used its latest measurement technologies, include the revolutionary REVO™ ultra-high-speed measuring head for coordinate measuring machines (CMMs), to deliver precise data capture of the legacy blade geometry that had carried Team Kiriasis to a world championship in 2005 and Olympic gold at Turin in 2006. The first step by the Renishaw-Siemens-Sescoi-Iscar partnership was to send the existing blades to Renishaw's UK research facility. There the five-axis measuring head for CMMs was used to scan the blades, quickly capturing many thousands of data points to enable form geometry to be defined in exact mathematical detail.

Unlike conventional touch scanning methods, which rely on speeding up the motion of the CMM's three axes in order to scan quickly, the low-mass measuring head combines horizontal and vertical rotary axes to perform high-speed "infinite" positioning of the touch probe. A 3D measuring device in its own right, the measuring head does the direction-changing measuring work to minimize CMM motion errors. Its low-mass, low-inertia design allows scanning at speeds of up to 500 mm/sec and capture of 4000 data points/sec vs. 200-300 data points for conventional scanning.

Once the blade geometry data was captured, both DXF and IGES files were created and sent electronically to Sescoi, a software specialist for tool and mold making that created a CAD/CAM program for a Siemens Sinumerik 840D CNC control and ShopMill HMI fitted to a DMG CNC milling machine located at tooling manufacturer Iscar Germany.

The vast number of data points to work with enabled high geometric and contouring accuracy as well as very smooth surfaces. The finishing program for the runner surfaces ran 5MB and contained about 100,000 lines, producing surfaces almost as polished as a mirror.

Following machining, the finished blades were checked for form while still fixtured on the machine tool, using an Renishaw OMP400 touch probe with industry-leading strain gage accuracy. A patented strain gauge sensing mechanism and advanced electronics allow lower, highly consistent contact forces with reduced pre-travel, enabling sub-micron 3D probe measurement and verification of the contoured surfaces.

Sandra Kiriasis was on hand to personally evaluate the machining. She received runners machined to exactly the same geometry as her championship-winning blades. Mounted to her sled, the new blades performed as well or even better than the old ones, continuing her edge over world-class competition.

Success at blade replication won Team Kiriasis both the 2006-2007 FIBT World Cup and World Championships. In fact, the team won the world championship by more than two seconds running the new blades, the biggest margin ever in championship history where races are usually decided by hundredths of a second.

After taking the gold medal at the FIBT championships in St. Moritz with brakeman Romy Losch, driver and team captain Sandra Kiriasis told TV broadcasters, "The blades are the secret of my success." Team Kiriasis' success highlights the impact that engineering technologies can have at the highest levels of competitive speed sports, noted Rainer Lotz, managing director of Renishaw GmbH, the company's German subsidiary.

"We know about the small margins between success and failure at the highest levels of international sports," he said. "Renishaw is already making significant technical contribution in the world of international motorsport, such as F1 and NASCAR racing, both in engine manufacture and on-car monitoring systems. We have been delighted to add our measurement expertise to the Team Kiriasis blade projects, and look forward to contributing to Sandra's continuing success."

Renishaw Inc., 5277 Trillium Boulevard, Hoffman Estates, IL 60192, 847-286-9953, Fax: 847-286-9974, www.renishaw.com.