Whilst machining heat is generated by the friction inherent into the sliding of the chip on the rake face of the insert, the temperature in the cutting zone of both the insert and the chip rises, facilitating adhesion and diffusion. These effects accelerate the insert wear, ultimately undermining the tool life. Therefore, a number of methods have been developed to control the heat generation. Most typically, metal working fluids are conveyed onto the rake face in the cutting zone, with negative implications on the contamination of the part. Many applications for instance in health care and optics are often hindered by this contamination. In this study, microfluidics structures internal to the insert were examined as a means of controlling the heat generation. Conventional and internally cooled tools were compared in dry turning of AA6082-T6 aluminium alloy in two 3 3 factorial experiments of different machining conditions. Statistical analyses supported the conclusion that the chip temperature depends only on the depth of cut but not on the feed rate or on the cutting speed. They also showed that the benefit of cooling the insert internally increases while increasing the depth of cut. Internally cooled tools can therefore be particularly advantageous in roughing operations.

Calibration is central to most measurement procedures. This is especially true in those cases where a large number of difficult-to-identify and difficult-to-control factors hinder the experimenters in their efforts to obtain reliable measurement results. Dimensional measurements of features on the micro-and nano-scale is one such case. A white light interferometer (WLI) microscope can perform measurements of a variety of measurands over a broad dimensional range: from surface texture characterisations on

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Any measurement method of a physical quantity cannot provide an exact unequivocal result due to the infinite amount of information necessary to characterise fully both the physical quantity to be measured and the measuring process. A quantitative indication of the quality of a measurement result needs therefore to be given to enable its reliable use. Uncertainty is one such indication. Provision of incorrect uncertainty statements for measurements performed by a coordinate measuring machine (CMM) may leads to very serious economic implications. In this study, the uncertainty of CMM measurements is estimated by a single parameter accounting for both systematic and random errors. The effects that environmental conditions (temperature), discretionary setup parameters (probe extension, stylus length) and measuring plan decisions (number of points) have on uncertainty of measurements is then investigated. Interactions between such factors were also shown to be significant.

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An increasing demand for an extended flexibility to model types and production volumes in the manufacture of large-size assemblies has generated a growing interest in the reduction of jig and fixtures deployment during assembly operations. A key factor enabling and sustaining this reduction is the constantly expanding availability of instruments for dimensional measurements of large-size products. However, the increasing complexity of these measurement systems and their set-up procedures may hinder the final users in their effort to assess whether the performance of these instruments is adequate for pre-specified inspection tasks. In this paper, mixed-effects and fixed-effects linear statistical models are proposed as a tool to assess quantitatively the effect of set-up procedures on the uncertainty of measurement results. This approach is demonstrated on a Metris Indoor GPS system (iGPS). The main conclusion is that more than 99 % of the variability in the considered measurements is accounted for by the number of points used in the bundle adjustment procedure during the set-up phase. Also, different regions of the workspace have significantly different error standard deviations and a significant effect on the transient duration of measurement. This is expected to affect adversely the precision and unbiasedness of measurements taken with Indoor GPS when tracking moving objects.

No abstract

The effect of the discretionary set-up parameters scan length and initial scanner position on the measurements of length performed with a white light interferometer microscope was investigated. In both analyses, two reference materials of nominal lengths 40 and 200 lm were considered. Random effects and mixed effects models were fitted to the data from two separate experiments. Punctual and interval estimates of variance components were provided.