The increasing acceptance of coordinate measuring machines (CMMs) has led to a need for greater understanding of probing systems. Successful gauging depends very much on the ability of the stylus to access a feature and maintain accuracy.
Sheffco has Renishaw styli available in a vast selection of sizes and materials to meet virtually every inspection need. Renishaw continues to use its expertise in design and innovation to enhance the existing comprehensive range of styli.
The main points to consider are:
Effective Working Length (EWL) is the approximate penetration distance that can be achieved by any ruby ball stylus before its stem fouls against the feature. Generally the larger the ball the greater the EWL. EWL can also be affected by assembly tolerances. For this reason Renishaw styli are assembled to exacting standards in controlled conditions.
|STYLUS||MATERIAL||SPHERICITY||DIAMETRIC TOLERANCE||HARDNESS||DENSITY||SURFACE FINISH||COEFF.OF EXPANSION @25C|
|Ruby balls||Synthetic ruby monocrystalline AI2 O3||All diameters: 0.15µm except 0.3: 0.25µm||±2µm||1700 Vickers||4g/cm3||0.025µm Ra||~5x10-6 /C|
|Ceramic hollow balls||White ceramic sintered alumina AI2O3||1µm||+0, -10µm||1500 Vickers||3.7 g/cm3||0.1µm Ra||~5x10-6 /C|
|Discs||Silver steel||1µm||±0.1 mm||450 Vickers||8g/cm3||0.4µm Ra||10.5x10-6 /C|
|Simple cylinder||Silver steel||Roundness 4µm||±50µm||200 Vickers||8g/cm3||1µm Ra||10.5x10-6 /C|
|Ball ended cylinder||Synthetic ruby||Concentricity, ball/sylinder 4µm||±3µm||1700 Vickers||4g/cm3||0.025µm Ra||~5x10-6 /C|
|Ball ended cylinder||Tungsten Carbide||±20µm end radius||±3µm||1500 Vickers||15g/cm3||0.4µm Ra||~5x10-6 /C|
|Simple pointer||Silver steel||Cone angle 30||-||300 Vickers||8g/cm3||0.4µm Ra||~10.5x10-6/C|
|Radius end pointer||Stainless steel/Tungsten Carbide||Cone angle 30||Tip radius
|1500 Vickers||15g/cm3||0.4µm Ra||~5x10-6 /C|
|Stylus stems and extensions||Stainless steel, BS970 303 541, Tungsten Carbide non-magnetic or White ceramic sintered alumina AI2O3||Stainless steel and Tungsten Carbide Stiffness <0.25µm/g except Ø0.3:0.4 µm/g ; Ceramic <0.5µm/g||0.4µm Ra||SS 16x10-6 /°C TC & Ceramic 5x10-6 /C|