Changes in electrical resistance during static and fatigue loading of unidirectional and cross ply carbon fibre reinforced polymer composites have been studied. The carbon fibres in the study were T300 and the matrix resins were Hexcel 914 and 920. It was found that changes in resistance during static tensile testing were about three per cent of the original resistance of the samples, while fatigue testing caused resistance changes of up to 10% of the original resistance, immediately prior to final failure. The initial linear portion of the resistance increase on static testing was reversible and could be attributed to reversible elastic strains in the fibres; later non-linear changes were a consequence of fibre fracture and were irreversible. Changes in resistance during fatigue also contained both reversible and non-reversible components. It was found that during fatigue testing the initial changes in resistance caused by the first few thousand cycles could be correlated with the eventual life. Samples with large initial resistance change had reduced lives compared with those with small changes in resistance. Fatigue lives of composite laminates may thus be predicted from monitoring of initial resistance changes. Many of the results could be explained via the parallel resistance model of conduction in composite laminates.

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This paper deals with an experimental study on the grindability of Al/SiC metal matrix composites (MMCs) in cylindrical grinding. The machining of MMCs is an important area of focus because finishing processes, such as grinding, to obtain a good surface finish and damage-free surfaces, are crucial for the application of these materials. Nevertheless, the grinding of MMCs has received little attention so far, and no detailed study on this subject has been carried out. In the present work, experiments were carried out to study the effect of cylindrical grinding parameters such as wheel velocity (VS), work piece velocity (VW), feed, and depth of cut, and the percentage of SiC volume fraction on the responses, such as grinding force (FT), surface roughness (Ra), and grinding temperature (GT). For each process condition, the average FT, Ra, and GT values were calculated from the three values measured on each ground surface. In the parameter study, the FT and Ra values decrease with an increase in VS and VW, and they increase with an increase in feed and depth of cut. The GT values are scattered in the range of 740–856 °C at the lower and higher levels of grinding variables. In the volume fraction study, the FT, Ra, and GT values increase with an increase in percentage of SiC volume fraction. Surface integrity of the ground surfaces was assessed using a scanning electron microscope (SEM). Cylindrical grinding using a 60 grit Al2O3 wheel at VS 2639 m/min, VW 26.72 m/min, feed 0.06 m/min, and depth of cut 10 µm, is recommended for the Al/SiC composites to obtain finely ground surfaces.

This paper deals with an experimental study on the grindability of Al/SiC metal matrix composites in cylindrical grinding. Machining of metal matrix composites (MMCs) is an area to be focused and finishing processes such as grinding to obtain a good surface finish and damage-free surfaces are crucial for the application of these materials. Nevertheless, grinding of MMCs has received little attention so far, thereby a detailed study on that has been carried out. In the present work, experiments are carried out to study the effect of grinding parameters; wheel velocity, work piece velocity, feed and depth of cut and SiC volume fraction percentage on the responses; grinding force, surface roughness and grinding temperature. Surface integrity of the ground surfaces is assessed using a scanning electron microscope (SEM). There are no cracks and defects found on the cylindrical ground surfaces at high wheel and work piece velocities, low feed and depth of cut.

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Aim: This research is about comparing the performance of poly-crystalline diamond (PCD) insert and uncoated cemented carbide insert for improving the material removal rate (MRR) in CNC turning. Materials and Methods: The material investigated in this research was SS316L. PCD insert was set as the experimental group and uncoated insert was set as the control group. The cutting parameters employed in this process were cutting speed, feed rate and depth of cut. Totally 27 samples per group were machined by using the selected parameters. Results: The mean MRR value obtained for the PCD tool is 0.22593 g/s, whereas it is 0.07600 g/s for the uncoated tool. The significance value obtained among the experimental group and control group is 0.000 (p<0.05). Conclusion:Within the limits of this study, the outcome of the research shows that MRR is more when the specimen is machined by PCD insert than machined by uncoated insert.

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