Authors: Zhan Qiang Liu, Xing Ai
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Abstract: Hard turning has the advantage of rapidly, elasticity and low energy consuming. It has
been a trend to replace the complex grinding processes, especially for small batch machining.The
surface roughness value of steel after being grinded will ranged in 0.1 to 1.6 μm Ra. This paper
points to the precision hard turning of the hardened mold steel, seeking the cutting conditions that
can be received in the surface roughness value below 0.1μm Ra, in order to replace the grinding
processes.
The precision dry turning test were conducted with ceramic cutting tools. The nose radius of the
cutting tool was 1.2 mm and the depth of cut was fixed at 0.05 mm. Through a series of turning test,
it can be found that, when cutting speed was at 80 to 200 m / min, and feed rate at 0.005 to 0.009
mm / rev, the surface roughness value would be all below 0.1μm Ra. It was superior to grinding
process. So we can say that, it is possible to replace the grinding process by hard turning when
machining the hardened mold steel.
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Authors: Chakaravarthy Ezilarasan, Ke Zhu, A Velayudham, K. Palanikumar
Abstract: Nimonic C-263 alloy is extensively used in the field of like aerospace, power generators and heat exchangers due to its higher thermal properties. In this work, an attempt has been made to investigate the effect of the cutting parameters (cutting speed, feed rate & depth of cut) on tool wear (flank wear) in the machining of this alloy with a PVD coated carbide insert. The experiments were conducted using Taguchi’s experimental design. A second order response surface model has been established between the cutting parameters and flank wear using response surface methodology. The predicted optimal value of flank wear for coated carbide is 0.190mm. The results are confirmed by conducting verification experiments.
794
Authors: Pedro Jose Arrazola, A. Villar, R. Fernández, J. Aperribay
Abstract: This article describes a practical machining training aiming that the students acquire the theoretical-practical knowledge of chip formation process. The training takes place after theoretical lessons of machining processes. Thus, this practice allows strengthening the knowledge gained during the lessons. The practical training lasts for five hours, and the student assisted by the teacher analyses the influence of some machining entry parameters (cutting speed, feed rate...) on exit parameters like: (I) cutting forces and power consumption, (II) surface roughness, and (III) chip typology. The practical session is carried out on an experimental set-up (Lathe CNC Danobar 65) equipped with sensors and devices to measure forces (sensor Kistler 9121) and power consumption. In addition, a portable rugosimeter (Hommelwerke) is employed to perform surface roughness measurements. No especial devices are needed for the chip typology analysis. In the case of cutting forces and power consumption, the following input parameters influences are analysed: feed rate, depth of cut and cutting speed. In the case of surface roughness analysis, the following input parameters influences are analysed: feed rate and nose radius of the cutting insert. Finally, regarding chip typology feed rate and depth of cut are examined. The experimental results are compared with model predictions (theoretical calculations) for the three issues studied. The students have to compare both results: theoretical an empirical and they need to explain the reasons when discrepancies appear. Results obtained during the last years demonstrate the student acquires better knowledge of the machining process, and at the same time realises of the process complexity.
83
Abstract: The paper deals with the experiments realized by means of cutting tool with linear cutting edge not parallel with the axis of the workpiece in order to be observed the suitable values of surface roughness characteristics in dependency on the feed and cutting speed. During experiments were machined three types of steels. Acquired data were statistical processed by regression analysis. The results of the measurements show that the investigated cutting tool enables to secure the same values of surface profile characteristics of steels as a classical cutting tool at finishing with the significant increase of the feed per revolution. It directly influences length of the technological operation time which is several times shortened and so the machining productivity can increase.
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