Renishaw Plc · LSE:RSW
Renishaw — Technical Presentation
38 slides from Renishaw's technical presentation
Slide 1: Renishaw touch-trigger probing technology
Renishaw touch-trigger probing technology Rugged and flexible solutions for discrete point measurement on CMMs
Slide 2: Touch-trigger probe technologies
Touch-trigger probe technologies Resistive • Simple • Compact • Rugged Strain-gauge • Solid-state switching • High accuracy and repeatability • Long operating life H-1000-8006-01-B Slide 2
Slide 3: Kinematic resistive probe operation
Kinematic resistive probe operation A trigger signal is generated A spring holds the stylus on contact with the component against the kinematic contacts surface and is used to stop and returns the probe to a the machine seated position following contact between the stylus and the part Three rods, ea
Slide 4: Kinematic resistive probe operation
Kinematic resistive probe operation • Probe in seated position All kinematics in contact Motion of machine H-1000-8006-01-B Slide 4
Slide 5: Kinematic resistive probe operation
Kinematic resistive probe operation • Probe in seated position • Stylus makes contact with component H-1000-8006-01-B Slide 5
Slide 6: Kinematic resistive probe operation
Kinematic resistive probe operation • Probe in seated position Reactive force • Stylus makes contact with component • Contact force resisted by reactive force in probe mechanism resulting in bending of the stylus Contact force H-1000-8006-01-B Slide 6
Slide 7: Kinematic resistive probe operation
Kinematic resistive probe operation • Probe in seated position Pivot about Contacts these contacts separate • Stylus makes contact with component • Contact force resisted by reactive force in probe mechanism resulting in bending of the stylus • Stylus assembly pivots about kinematic contacts, result
Slide 8: Kinematic resistive probe operation
Kinematic resistive probe operation • Probe in seated position • Stylus makes contact with component • Contact force resisted by reactive force in probe mechanism resulting in bending of the stylus • Stylus assembly pivots about kinematic contacts, resulting in one or two contacts moving apart • Tri
Slide 9: Kinematic resistive probe operation
Kinematic resistive probe operation Kinematic Electrical switching Section through kinematics: attached • Electrical circuit through contacts to stylus • Resistance measured Current flows • Contact patches reduce in through kinematics size as stylus forces build Kinematics bonded to (and Close-up vi
Slide 10: Kinematic resistive probe operation
Kinematic resistive probe operation Electrical switching Resistance • Resistance breaches threshold and probe triggers Force on kinematics when stylus is in • Kinematics are still in free space contact when probe triggers • Stylus in defined position Trigger • Current cut before threshold kinematics
Slide 11: Factors in measurement performance
Factors in measurement performance Pre-travel • Stylus bending under contact loads before trigger threshold is reached • Pre-travel depends on FC and L • Trigger is generated a short distance after the stylus first touches the component FC × L = F S × R L and FS are constant FC is proportional to R
Slide 12: Factors in measurement performance
Factors in measurement performance Pre-travel variation - ‘lobing’ Top view • Trigger force depends on probing direction, since pivot point varies • FC is proportional to R • Therefore, pre-travel varies around the XY plane H-1000-8006-01-B Slide 12
Slide 13: Factors in measurement performance
Factors in measurement performance Pre-travel variation - ‘lobing’ High force Low force direction: direction: R1 > R2 FC1 > FC2 Pivot Pivot point point H-1000-8006-01-B Slide 13
Slide 14: Factors in measurement performance
Factors in measurement performance Pre-travel variation - ‘lobing’ • Trigger force in Z direction is higher than in XY plane • No mechanical advantage over spring • FC = FS • Kinematic resistive probes exhibit 3D (XYZ) pre-travel variation • Combination of Z and XY trigger effects • Low XYZ PTV usef
Slide 15: Factors in measurement performance
Factors in measurement performance Probe calibration • Pre-travel can be compensated by probe calibration • A datum feature (of known size and position) is measured to establish the average pre-travel • Key performance factor is repeatability Limitations • On complex parts, many probing directions m
Slide 16: Factors in measurement performance
Factors in measurement performance Typical pre-travel variation Scale in µm • XY plane Probe: TP6 Stylus: 50 mm Pre-travel variation: 3.28 µm Trigger force: 15 gram Repeatability (2 Sigma): 0.5 µm H-1000-8006-01-B Slide 16
Slide 17: Factors in measurement performance
Factors in measurement performance Repeatability • The ability of a probe to trigger at the same point each time • A random error with a normal distribution • For a given probe and probing condition, repeatability is equal to twice the standard deviation (2) of the normal distribution • 95% confide
Slide 18: Factors in measurement performance
Factors in measurement performance Hysteresis • Error arising from the direction of the preceding probing move • Maximum hysteresis occurs when a measurement follows a probing moves in opposite directions to each other in the probe’s XY plane • Hysteresis error increases linearly with trigger force
Slide 19: Factors in measurement performance
Factors in measurement performance Ranked in terms of importance Repeatability • Key requirement of any trigger probe • Fundamental limit on system measurement performance • Hysteresis contributes to measurement repeatability Pre-travel variation • Can be calibrated, provided all probing directions
Slide 20: Kinematic resistive probe technology
Kinematic resistive probe technology Simple electro-mechanical switching • Resistive probes use the probe kinematics as an electrical trigger circuit • Pre-travel variation is significant due to the arrangement of the kinematics H-1000-8006-01-B Slide 20
Slide 21: Kinematic resistive probe characteristics
Kinematic resistive probe characteristics • Extremely robust • Universal fitment • Compact • Simple interfacing • Good part access • Cost-effective • Suitable for long extensions • Finite operating life • Good repeatability • Electro-mechanical switching • Excellent performance with shorter styli •
Slide 22: TP20 stylus changing probe
TP20 stylus changing probe Concept • Direct replacement for TP2 • Ultra-compact probe at just Ø13.2 mm • TP20 features fast and highly repeatable stylus changing • Manual or automatic • Enhanced functionality through extended force and extension modules H-1000-8006-01-B Slide 22
Slide 23: TP20 stylus changing probe
TP20 stylus changing probe Benefits • Reduced cycle times achieved by fast stylus changing without re-qualification • Optimised probe and stylus performance with seven specialised probe modules • Easily retrofitted to all Renishaw standard probe heads (M8 or autojoint coupling) • Compatible with exi
Slide 24: TP20 stylus modules
TP20 stylus modules Optimal measuring performance • Seven specialised probe modules allow optimisation of stylus arrangement for best accuracy and feature access in all user applications • Module attaches to probe body via a quick release, highly repeatable kinematic coupling • Module range covers a
Slide 25: Comparative module and stylus lengths
Comparative module and stylus lengths Soft materials General use Longer or heavier styli Grooves and undercuts Reach up to 125 mm (5 in) H-1000-8006-01-B Slide 25
Slide 26: Strain-gauge probe technology
Strain-gauge probe technology • Solid state switching • Silicon strain gauges measure contact forces transmitted through the stylus • Trigger signal generated once a threshold force is reached • Consistent, low trigger force in all directions • Kinematics retain the stylus / not used for triggering
Slide 27: Strain-gauge probe operation
Strain-gauge probe operation Force sensing Silicon strain gauges • Four strain gauges are mounted on webs mounted on webs inside the probe body (1 out of 4 shown) • X, Y and Z directions, plus one control gauge to counter thermal drift • Low contact forces from the stylus tip is transmitted via the
Slide 28: Strain-gauge probe operation
Strain-gauge probe operation Low lobing measurement Scale in µm • Trigger force is uniform in all directions • Very low pre-travel variation Probe: TP7M Stylus: 50 mm M4 Maximum variation: 0.34 µm Sensitivity: HIGH H-1000-8006-01-B Slide 28
Slide 29: Strain-gauge probe operation
Strain-gauge probe operation Lobing comparison • Plots at same scale Strain-gauge XY PTV = 0.34 m Kinematic resistive XY PTV = 3.28 m H-1000-8006-01-B Slide 29
Slide 30: Strain-gauge probe characteristics
Strain-gauge probe characteristics High accuracy and repeatability • Probe accuracy even better than standard kinematic probes • Minimal lobing (very low pre-travel variation) Reliable operation • No reseat failures • Suitable for intensive "peck" or "stitch” scanning • Life greater than 10 million
Slide 31: TP7M strain-gauge probe
TP7M strain-gauge probe Concept • 25 mm (1 in) diameter probe • Autojoint mounted for use with PH10M PLUS • Multi-wire probe output H-1000-8006-01-B Slide 31
Slide 32: TP7M strain-gauge probe
TP7M strain-gauge probe Benefits • Highest accuracy, even when used with long styli - up to 180 mm long ("GF" range) • Compatible with full range of multi-wired probe heads and extension bars for flexible part access • Plus general strain-gauge benefits: • Non-lobing • No reseat failures • Extended
Slide 33: TP7M performance
TP7M performance Uni - directional repeatability 0.3 0.25 0.2 Microns 0.15 Test results from five probes 0.1 0.05 0 0 2 4 6 8 10 12 14 16 18 20 No. of triggers (*1,000,000) H-1000-8006-01-B Slide 33
Slide 34: TP7M performance
TP7M performance XY (2D) form measurement deviation 0.6 0.5 0.4 Microns 0.3 Test results from five probes 0.2 0.1 0 0 2 4 6 8 10 12 14 16 18 20 No. of triggers (*1,000,000) H-1000-8006-01-B Slide 34
Slide 35: TP200 stylus changing probe
TP200 stylus changing probe Concept • TP2-sized probe, with strain gauge accuracy • Stylus changing for greater flexibility and measurement automation • 2-wire probe output (like TP20) Benefits • Long stylus reach - up to 100 mm long ("GF" range) • Match stylus to the workpiece using high-speed styl
Slide 36: TP200 stylus modules
TP200 stylus modules Optimal sensor performance • 6-way operation ±X, ±Y and ±Z • Two types of module: • SF (standard force) • LF (low force) provides lower overtravel force option for use with small ball styli and for probing soft materials • Detachable from probe sensor via a highly repeatable mag
Slide 37: Trigger probe measurement performance comparison
Trigger probe measurement performance comparison H-1000-8006-01-B Slide 37
Slide 38: Renishaw touch-trigger probing technology
Renishaw touch-trigger probing technology Thank you for your attention…