Federal Department of Justice and Police FDJP Federal Office of Metrology METAS Ultra precision µcmm using a low force 3D touch probe F. Meli, A. Küng, R. Thalmann Federal Office of Metrology (METAS)
Ultra precision µcmm using a low force 3D touch probe Contents: Probing force and surface damage Low force 3D-probe head Ultraprecision CMM Probe sphere calibration Scanning CENAM CMM Club I R. Thalmann I 26.10.2006 I 2
Tactile measurements of small objects Application fields: Micro technology Micro- and fiber-optics Data storage Watch industry Medical industry Automotive industry CENAM CMM Club I R. Thalmann I 26.10.2006 I 3
Surface deformation at tactile probing The smaller the probe sphere the larger the surface pressure at contact the larger the risc of plastic deformation CENAM CMM Club I R. Thalmann I 26.10.2006 I 4
Maximum Force versus sphere diameter Hertz theory assuming a contact pressure of 1000 MPa 250.0 200.0 force /mn 150.0 100.0 50.0 0.0 p = 1000 MPa 0 0.2 0.4 0.6 0.8 1 sphere diameter /mm Ø 4.0: 3.6 N Ø 0.3: 22 mn Ø 0.2: 10 mn Ø 0.1: 2.5 mn low stiffness CENAM CMM Club I R. Thalmann I 26.10.2006 I 5
Experimental verification by AFM Conditions: conventional high end CMM with analogue probe (SIP) Ø 0.6 mm probe material aluminium depth: 330 nm CENAM CMM Club I R. Thalmann I 26.10.2006 I 6
Dynamic forces m= 13.25 v 2 Y 5 E *4 db 3 v Y E = * = approach speed = tensile equivalent yield strength Young' s modulus Ref.: W.P. van Vliet et al., Annals of CIRP, Vol. 45/1, 1996, p. 483 CENAM CMM Club I R. Thalmann I 26.10.2006 I 7
Maximum probe mass versus sphere diameter contact pressure: 1000 MPa probe mass /g 100.00 80.00 60.00 40.00 20.00 v = 0.1 mm/s v = 0.5 mm/s v = 1.0 mm/s v = 1 mm/s: Ø 4 mm m = 1.8 kg Ø 0.1 mm m = 28 mg slower! v = 0.1 mm/s: Ø 0.1 mm m = 2.8 g 0.00 0 0.5 1 1.5 2 sphere diameter /mm CENAM CMM Club I R. Thalmann I 26.10.2006 I 8
Probe design and kinematics (know how) Clavel, Patent n 672089A5 CENAM CMM Club I R. Thalmann I 26.10.2006 I 9
Probe sensor design CENAM CMM Club I R. Thalmann I 26.10.2006 I 10
Probe coordinate system X Y Z CMM CMM CMM = 0.8165 X = = 0.5774 X P P 0.4082 Y 0.7071 Y + 0.5774 Y P P P 0.4082 Z 0.7071 Z + 0.5774 Z P P P CENAM CMM Club I R. Thalmann I 26.10.2006 I 11
The measurement procedure contact contact CENAM CMM Club I R. Thalmann I 26.10.2006 I 12
Ultraprecision CMM project of Philips CFT Abbe principle: probe sphere x z x interferometer beams Theo Ruijl, Ultraprecision Coordinate Measuring Machine Thesis, Philips CFT, Eindhoven, The Netherlands CENAM CMM Club I R. Thalmann I 26.10.2006 I 13
Ultraprecision CMM project of Philips CFT Metrology loop: Theo Ruijl, Ultraprecision Coordinate Measuring Machine Thesis, Philips CFT, Eindhoven, The Netherlands CENAM CMM Club I R. Thalmann I 26.10.2006 I 14
Ultraprecision CMM project of Philips CFT Theo Ruijl, Ultraprecision Coordinate Measuring Machine Thesis, Philips CFT, Eindhoven, The Netherlands CENAM CMM Club I R. Thalmann I 26.10.2006 I 15
New machine controller made at METAS High Level LAN Machine Controller Quindos LabView HP Interferometer Boards (ISA) 3-axis motion control (PCI) Stage gravity compensation Probe head interface (PXI) Refraction Index (p, T air, H rel, CO 2 ) Material and Frame Temperatures Joystick Security and resources error corrections metrology know how CENAM CMM Club I R. Thalmann I 26.10.2006 I 16
Calibrations and corrections Goal: Traceable measurements Laser wavelength Interferometer alignment: cosine, Abbe, guiding errors Ambient: Temperature, pressure, humidity, CO 2 Reference mirror-system Probing sphere calibration pitch Y-Axix Y axis angular drift /sec 0.3 0.2 0.1 0 0 10 20 30 40 50 60 70 80-0.1-0.2-0.3 y = -0.0002x 2 + 0.0141x - 0.1637-0.4-0.5 Y axis position /mm CENAM CMM Club I R. Thalmann I 26.10.2006 I 17
Flatness corrections of reference mirrors X- Axis form error = 51 nm Y- Axis form error = 63 nm Z- Axis form error = 233 nm CENAM CMM Club I R. Thalmann I 26.10.2006 I 18
Measurement on 0.5 mm sphere roundness of the measured sphere (nm) 60 30 0-30 -60-90 -120-150 0 60 120 180 240 300 Average Sphere diameter: 0.5 mm, roundness 64 nm Measured in 6 orientations St. dev. = 9.8 nm CENAM CMM Club I R. Thalmann I 26.10.2006 I 19
Measurement on 0.5 mm sphere roundness of the probing sphere (nm) 40 20 0-20 -40-60 -80-100 0 60 120 180 240 300 Average Probe diameter: 0.3 mm, roundness 40 nm Measured in 6 orientations St. dev. = 8.4 nm CENAM CMM Club I R. Thalmann I 26.10.2006 I 20
Extended set of probes ranging from 1 mm to 0.125 mm 1 mm 125 µm CENAM CMM Club I R. Thalmann I 26.10.2006 I 21
Probe diameter determination using 3 spheres Ma = R1a + R2a probe sphere y Mb = R1a + R3a Mc = R2a + R3a z object sphere Ma x x z y x α α x R1a R2a R3a Side view Top view CENAM CMM Club I R. Thalmann I 26.10.2006 I 22
Absolute calibration of 3 reference spheres The 3 spheres were measured against each other providing, by means of an error separation technique, an absolute mapping of their dimension. Equator of sphere 1 Diameter: 1.000827 mm Roundness: 48 nm 0.8 0.6 0.4 0.2 0-0.8-0.6-0.4-0.2 0 0.2 0.4 0.6 0.8-0.2-0.4-0.6-0.8 Equator of sphere 2 Diameter: 1.000852 mm Roundness: 26 nm 0.8 0.6 0.4 0.2 0-0.8-0.6-0.4-0.2 0 0.2 0.4 0.6 0.8-0.2-0.4-0.6-0.8 Equator of sphere 3 Diameter: 1.000796 mm Roundness: 34 nm 0.8 0.6 0.4 0.2 0-0.8-0.6-0.4-0.2 0 0.2 0.4 0.6 0.8-0.2-0.4-0.6-0.8 Error magnification: 10 000 CENAM CMM Club I R. Thalmann I 26.10.2006 I 23
Absolute calibration of 3 reference spheres Sphere 2 Diameter: Roundness: 1.000859 mm 33 nm Sphere 1 Sphere 3 Diameter: 1.000824 mm Diameter: 1.000804 mm Roundness: 51 nm Roundness: 53 nm CENAM CMM Club I R. Thalmann I 26.10.2006 I 24
Controlled Freeform-Scanning Scan speed 0.1 mm/s to 0.6 mm/s point density up to 300 p/mm propagation deflection Scanning points CENAM CMM Club I R. Thalmann I 26.10.2006 I 25
ISO10360-4 scanning acceptance test Form Error: 87 nm Sphericity: 60 nm Surf. roughness: 15 nm Calibration error: 15 nm CENAM CMM Club I R. Thalmann I 26.10.2006 I 26
Scanning of a 1 mm sphere equator 10 scan measurements with a Ø 0.3 mm probe 0.8 0.6 repeatability : 5 nm (1σ) surface texture : ~10 nm equator form error :48 nm 0.4 0.2 0-0.8-0.6-0.4-0.2 0 0.2 0.4 0.6 0.8-0.2-0.4 Cir 10 Cir 9 Cir 8 Cir 7 Cir 6 Cir 5 Cir 4 Cir 3 Cir 2 Cir 1-0.6-0.8 CENAM CMM Club I R. Thalmann I 26.10.2006 I 27
Roundness comparison measurement Form error: Filtered with 50 upr Talyrond 73: (93 ± 10) nm µcmm: (90 ± 20) nm Deviation to average diameter (mm) -0.01 Difference: -0.03 Max: 15 nm -0.05 St. dev.: 5 nm -0.07 0.03 0.01 Talyround Scanning 0 Scanning 120 Scanning 240 Average scanning CENAM CMM Club I R. Thalmann I 26.10.2006 I 28
CENAM CMM Club I R. Thalmann I 26.10.2006 I 29 Thank you