Papers by Keyword: Microturning

Abstract: In this work, an online acoustic emission (AE) monitoring system is developed, to investigate the effect of tool wear during the microturning of titanium alloy with a tungsten carbide insert of nose radius 0.1 mm. The AE signal parameters were analyzed in time domain, frequency domain and discrete wavelet transformation (DWT) techniques to correlate with the tool wear status. The root mean square (AE_RMS) and specific AE energies are also computed for the decomposed AE signals, using the DWT. The results demonstrated that dominant frequency and DWT techniques are found to be most suitable for online tool condition monitoring, using AE sensors in the microturning of titanium alloy.

Abstract: In the present work, an attempt has been made to monitor the tool condition status during microturning of aluminium alloy (AA 6061) using multiple sensors such as cutting force dynamometer, acoustic emission (AE) and accelerometer. The tool wear (nose wear) is correlated with surface roughness (R_a), chip width, thrust force (F_x), tangential force (F_y), feed force (F_z), AE_RMS and vibration signals. It is observed that R_a, chip width and cutting forces are increased with increase in the tool wear. Among the cutting forces, the tangential force (F_y) is found to be more sensitive to the tool wear status compared to that of the thrust force (F_x) and feed force (F_z). From the signal analysis, it is observed that during machining with good tool condition, the dominant frequency of the AE_RMS and vibration signals are found to be 81 kHz-110 kHz and 2.07 kHz-3.84 kHz respectively, whereas with the worn out tool the dominant frequencies are shifted to higher levels. Chip morphological studies indicated that favourable type of chips are formed upto 40^th minute and unfavourable chips are observed from 41^st minute to 60^th minute.

Abstract: In the paper the concept of electrochemically assisted microturning process was presented. This is a hybrid machining process in which the microcutting directly removes the material while the electrochemical passivation process is changing the conditions of cutting. The experimental part consist of description of passive layer formation process on 304 steel samples and results discussion of passive layer thickness and mechanical properties measurement with ellipsometry and nanoindentation technique.

Abstract: Miniature parts with high accuracy and precision are increasingly in demand for various industries. Microturning is a process for fabrication of such miniaturized parts with features that range from tens of micrometres to a few millimetres. In this present study commercially available Oxygen Free High Conductivity (OFHC) copper rods have been microturned using cermet inserts of 0.1mm nose radius. The effects of machining parameters on the surface generated have been discussed. Scanning electron microscope images of worn out inserts and machined surfaces are analysed to ascertain the wear mechanism and study the nature of the surface generated.