A montage of styli from Renishaw
Renishaw (www.renishaw.com), the inventor of the touch trigger probe, has developed a line of precision styli from a range of high-performance materials including stainless steel, tungsten carbide, ceramic and carbon fibers that are designed to provide a comprehensive range of tools for CMM and machine tool measurements.
The company said its styli are designed to meet every measurement challenge, with the correct rigidity and tip sphericity are vital to probe measurement accuracy. The stainless steel styli are for application versatility, tungsten carbide styli are for high stiffness at small diameters, ceramic for weight savings at large diameters, and carbon fiber for maximum stiffness, low mass and superior vibration damping in long styli (above 50 mm).
Renishaw produces its styli stems on CNC machine tools to exacting requirements, and produces its stylus balls to high standards then bonds them to the stems to assure joint integrity.
The styli are available with balls of synthetic ruby, silicon nitride, and zirconia, all of are produced with hgih levels of purity, finish and sphericity.
The company said its ruby balls are made from one of the hardest known materials. They are created from 99 percent aluminum oxide crystal that is cultured at 2000°C., and are the industry standard for the vast majority of measurement requirements.
Renishaw styli feature Grade 5 ruby balls, with sphericity of 0.13 μm (0.0000051 in.) as standard. Renishaw also offers Grade 3 highaccuracy styli providing sphericity of 0.08 μm (0.0000031 in.)
To avoid degrading that sphericity, no mounting hole is drilled into the ball. Instead, the ball is bonded into a spherical cup machined into the styli stem. Grade 3 styli stems are coated in titanium nitride, giving them a gold color finish.
The other two ball materials are recommended for special situations and materials — silicon nitride for aluminum and zirconia for scanning applications on cast iron.
Renishaw said its styli are available in a comprehensive range of sizes and configurations, including straight styli and ball, star, disc, cylinder, pointer, and ceramic hollow ball. The company also offers a selection of accessories and tools, and styli for Zeiss probes and specialized models for Faro arm CMMs. It also provides custom stylus designs for unusual applications.
