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The application of fractal geometry methods for characterizing the properties of surfaces of materials and products is described. The terminology of the standard GOST R ISO 25178-2-2014, “Geometric characteristics of products (GPS). Surface structure. Areal. Part 2. Terms, definitions and parameters of surface structure.” The functions provided by the standard for calculating fractal dimension are presented; algorithms for their calculation in the Mathcad environment are described. We give an example of calculations based on the results of measurements of the heights of surface irregularities of a gauge block, obtained using an atomic force microscope.

Many workers have published various methods to measure refractive index of various liquids. Mostly, the measurement results are not traceable to SI units. A novel method is developed at CSIR-NPL, India (NPLI) to measure refractive of index of liquids using gauge blocks, metrological microscope and displacement laser interferometer. A vessel with flat bottom is chosen to hold the liquid under test. A pair of gauge blocks of different lengths is fixed in the vessel. The vessel is arranged under a vertically movable microscope. A calibrated displacement laser interferometer is attached to the microscope stage. The microscope is focused to the surface of gauge block before poring liquid. After poring liquid in the vessel, the microscope is moved vertically to regain the focussed image of surface of submerged gauge blocks. The measurement method is simulated mathematically. The refractive index of liquid medium is calculated using this mathematical model. Refractive index of water, isopropyl alcohol is measured. Various error contributing sources are identified. The measurement uncertainty is evaluated.

In ISO/IEC Guide 99:2007, i.e. the International Vocabulary of Basic and General Terms in Metrology-3rd edition (VIM 3), the term “traceability” is replaced by “metrological traceability”, giving it a new definition as property of a measurement result which can be related to a reference. In essence, “metrological traceability” can offer an evidence of measurands tracing to the primary standards which can realize the SI units, and offer a documented unbroken chain of calibrations, thus considered as one of the most important terms in VIM 3. National Measurement Laboratory (NML, Chinese Taipei) has long operated its main mission of calibration implemented along with peer assessed traceability of its measurement systems, which demonstrate a calibration hierarchy conventionally in schematic approach. In dealing with definition of the new term “metrological traceability” in VIM 3, this paper elaborates in taking additionally a newly mathematical approach rather than schematic approach only to realize the practical interpretation of “metrological traceability” to show how the unbroken calibration chain is functioning seamless and robust on the gauge block measurement system in NML. Through such study activities, we well assure our strong confidence on technology inheritance of gauge block and the other measurement systems with sufficient metrological know-how in NML, which can continually pass to each entry level metrologist.

A displacement interferometer is described for measuring gauge blocks, in which a spatial filter is used to combine a laser beam with a white-light beam, and the length of the block is calculated from the phase differences of the laser signal corresponding to the centers of gravity of the achromatic fringes from the gauge and from the reference plate.

This paper discusses the optimal parameters using the Taguchi method, but also analyses the Weibull modulus through reliability engineering for polishing ceramic gauge blocks. The optimal polishing parameters for removal rate thus obtained include highest speed, greatest load and a diamond particle size of 3 μm and 30% concentration. The analysis of variance shows that the most significant polishing parameters for removal rate are speed (39.8%) and load (39.2%), followed by concentration (17.9%) and diamond size (3.1%). The optimal polishing parameters for the Weibull modulus are found to be low speed and medium or high load, regardless of diamond size and concentration.

A probe test device has been developed to assess CMM touch trigger probe errors. A precise single axis translational table triggers the probe through the use of gauge blocks fixed to the table carriage. The position of the carriage is monitored by a laser interferometer. The gauge block surface is brought into contact with the probe ball tip until the probe is triggered at which point the coordinate position is displayed by the laser. The probe is rotated 360° using the motorized probe head in 7.5° intervals and the coordinate of each position is computed. Repeatability errors (i.e. the ability of the probe to trigger at the same point each time with a 95% confidence level) and pre-travel variation (i.e. the distance traveled by a probe between the actual touching of a surface and the trigger event) are then calculated. This paper reports the measurement strategy and the design of the prototype rig. Results are also provided to demonstrate the test apparatus performance.

A description is given of the Kosters hardware and software facility for recording and processing arrays of video data when measuring gauge blocks of up to 100 mm in length using a Kosters interferometer. It is shown that when using the Kosters hardware and software facility the standard uncertainty of a result of measuring the lengths of gauge blocks is smaller than a few nanometers.

A lapping experiment and performance analysis for the gauge block is given first. Then, the experimental design using the Taguchi method was employed to optimise the polishing parameters. Results showed that the carrier with circular holes produced better surface roughness in the lapping experiment. The analysis of variance (ANOVA) of the polishing experiment found that the removal rate was a function of pressure and speed. This finding agrees with Preston's equation. The optimum conditions for high removal rate in the polishing experiment are: pressure, 56.27 kPa; concentration, 15%; speed, 200 r.p.m. The optimum conditions for good surface roughness in the polishing experiment are: pressure, 18.75 kPa; concentration, 10%; speed, 150 r.p.m.

The first stage in increasing the accuracy of measurements of the linear dimensions of precision parts the exact reproduction of a certified gauge block, is investigated. Recommendations are made on the use of a new method to evaluate the increase in the accuracy of evaluation of unmonitored lapping-in and contact deformations during measurements.

1. The thickness of the surface films formed during production decreases in a regular manner with decreasing roughness and with a roughness between 0.03 and 0.06 μ provides stable dimensions for gauge blocks. 2. It appears that 0.02–0.03 μ is a critical value for roughness, and that if it is decreased during lapping in building up a block, a firm and close coupling is obtained, which, however, may lead to seizing (jamming) and the formation of a cold welded seam (speedy deterioration) on the measuring surface of the gauge, and if the roughness is increased, it leads to a loss of the wringing effect and a rise in the dimensions of the gauge block. 3. The tangential resistance force may serve as a criterion of the tendency to wring. 4. A specified method of lapping end gauges should be included in the instructions for checking them.

1. A thin lubricating layer on the surface of block gauges is a prerequisite for their effective ringing capacity. 2. The thickness of this layer,under standard conditions of ringing, which provides a maximum adhesion of plates with a high grade of smoothness (13b), is constant, and equals approximately 0.01 µ. The variations in the length of a gauge block due to the lubricating layers is a multiple of their number and thus will lie within tolerances. 3. The smoother the plate surfaces are made, the firmer becomes their adhesion obtained by lapping, providing the remaining factors stay constant. 4. Friction or adhesion of plates can serve equally well as a criterion of their ringing capacity. 5. The static friction of plates under conditions of boundary lubrication follows the binomial lawf=µ(sp0+N). 6. The ringing capacity of plates is proportional to their hardness. 7. Nonpolar substances, as well as highly polar organic substances, are less effective in lapping than lubricating compounds of the type of the factory lubricant “Kalibr.” It is advisable to conduct research for new lubricants by mixing polar and nonpolar substances. 8. The firmness of adhesion between the plates is determined by the physicochemical properties of chain molecules in the lubricants, the energy of their adhesive and cohesive interaction, the peculiarities of the layer structure, and the variations of its properties as a function of the distance between the solid surfaces. 9. It is expedient to conduct research into the possibility of self-lubrication of the plates.