Length section: New calibration and research services O Kruger October 2015 T026
Overview Traditional traceability chart Traceability chart with length R&D projects Overview of Various R&D projects Conclusion
Traceability chain SI unit of length R&D Dissemination of Knowledge & Technology Maintenance & Calibration of Standards SANAS Accredited Laboratories NMISA Industry
Traceability chain with R&D projects
Research on the SI unit SI Unit for length: The metre is the length of the path travelled by light in vacuum during a time interval of 1 299792458 of a second. Currently NMISA reproduce the unit by a Iodine stabilised HeNe laser. Laser interferometers are calibrated against the standard by generating a beat frequency and measure the offset to the standard laser.
Research at the SI unit, frequency comb A frequency comb allows a direct link from radio frequency standards to optical frequencies. Current frequency standards such as atomic clocks operate in the microwave region of the spectrum, and the frequency comb brings the accuracy of such clocks into the optical part of the electromagnetic spectrum
Refractometer for the refractive index measurements V.O.L. compensation The metre is defined as the speed of light in a vacuum but we measure in air. Therefore we need to make a correction due to the difference in refractive index. (n 1) tp = p(n 1) s. 1+10 8 p(0,5953 0,009876t) 93 214,60 (1+0,0036610 t ) This is at standard conditions (t = 20 C, p = 100 kpa, 0,04% CO 2 content) Reading Number Refractive index from refractometer Refractive index from calculation (Edlin) Refractive index from cal. (Ciddor) Refractive index from cal. (Zygo) Refractive index from cal. (Agilent Ver 2.003) 1 1.00023301 1.000232952 1.000232952 1.0002329 1.000232954 f2 Optical parallel Zygo laser f1 + f2 Vacuum tube f1 f1 Quater wave plate f2
Double ended interferometer system (gauge block calibration) Gauge blocks are the most used dimensional standard in industry and second most important on the traceability chain, after laser interferometers Ongoing research is phase correction and a newly design DEI Folding mirror Gauge block a Came ra Cube beam splitter Folding mirror with PZT cotroll L b Laser Turning mirror
Gravity national standard Gravity is used by many; Geodesy, Geophysics and Metrology Metrology, Forces and Pressure measurements and calibration
Improvement Surface texture calibration capability NMISA completed the upgrade of it s surface texture calibration facility. The new instrument has a resolution of only 0,2 nm over a 10 mm range and 120 mm travel. Currently adding 3D measuring capability From EURAMET L.K8 2013, inter laboratory comparison NMISA
Improvement in roundness measuring machine accuracies NMISA in the process of purchasing a 10nm accurate roundness measuring machine.
Error separation in roundness measuring
Angle calibration of theodolites Error separation using 5 reading heads achieve very high accuracy, repeatability of better than 0,05, and is self calibrated.
Coordinate metrology at NMISA. Laser tacker, 160 m range Industrial CMM, 2 m range with 3 µm accuracy High accurate CMM, 0,35 µm accurate µcmm, having a 35 µm diameter probe
Length in nano metrology Installation of Atomic force microscopy (AFM) having a range of 100µm x 100µm with 10µm height. Having a resolution of 0,1 nm but flatness of stage will influence the overall accuracy.
Length in nano metrology Index table Beam splitter Calibration of diffraction gratings use as standard for both the AFM and the SEM Calibration of gratings on diffractometer and measured with AFM Laser Grating Detector fm 360 340 320 300 280 260 240 220 200 180 160 140 120 100 80 60 40 20 0
Traditional micrometers versus new micrometers Micrometers are some of the oldest measuring instruments but are still used in industry for measuring artefacts. Till recently, micrometers have a specification to 3 µm for the linear accuracy. (BS 870 and ISO 3611) New micrometers have linear accuracy of 0,5 µm and flatness of 0,3 µm.
Measuring equipment for industry and NMIs As part of the new strategy in NMISA, the length section is developing measuring systems for the local and Africa metrology community. The line scale system was developed based on software which was required in-house for NMISA own line scale measuring systems. Twelve of these systems were delivered to African NMIs
Cell phone apps. If you can image it, there is probably an App for it already Total Number of Apps 62 Number of Unique Parameters Found 11 Number of Measurement Parameters by Apps 80 Number of Sensor Types 7
Dimensional Measurement Apps
Experimental Results so far Actual Cell A Cell B Cell C Cell D Length 1600 ± 0,5 1562,34 1535,86 1600 1737,75 Width 1000 ± 0,5 1006,67 1003,54 1190 952,59 Depth 180 ± 0,5 207,91 225,71 180 257,67
Three Dimensional printing, additive manufacturing. Design part to be printed in titanium. Check for dimensional accuracy(length, flatness, etc.), surface texture, thermal expansion and long term dimensional stability.
Three Dimensional printing, additive manufacturing. Modification of 3D printers by adding laser interferometers.
Conclusion The length strategy is to service the South African and African industries through various R&D projects. The projects are selected to have an output which: i) to improve the National Measurement Standards ii) improve measurements at industry level iii) develop Human resources at NMISA and industry Invite industry to contact NMISA with measurements difficulties