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EN
The study presents the influence of the anti-wear coatings and the type of material from which the cutting tools are made of on the cutting temperature occurring on the tool. The cutting tools made of boron nitride and tungsten carbide composite were investigated. The methodology of measuring the cutting temperature using the thermoelement and thermovision techniques was presented. The results of the temperature measurements occurring on the cutting tool in the cutting zone were compared. The paper also presents a method of determining the effective emissivity of the tested tools, necessary for the correct temperature measurement using the non-contact method. The obtained data were interpreted and the relationships described, and then the results obtained were discussed.
EN
The nickel-based alloy Inconel718 is a multi-component complex alloy. There exists complex cutting deformation, higher cutting temperature, higher cutting force and formation of serrated chip in the machining process. However, the formation time of every saw tooth unit in serrated chip is very short. It is difficult to use traditional method to analyze the chip at any time. Simulation analysis, integrated with the experimental results, was used to study the whole process of cutting deformation. The Johnson–Cook (JC) constitutive model of Inconel718 under high speed and high strain rate is established through split Hopkinson pressure bar (SHPB) test. The finite element method was used to study the deformation process. Combining the analysis of metallographic pictures which were obtained in the cutting experiment, the plastic behavior evolution of material in the cutting zone is deeply studied to further reveal the forming mechanism of serrated chip. The results showed that the local temperature in the cutting zone increased rapidly. The appearance of thermal softening of materials led to the change of stress distribution in the cutting zone. The thermoplastic shear instability further appeared which resulted in the shear localization, subsequently leading to the uneven deformation of chip and then serrated chip formed.
EN
Research in 60s and 70s started to deal with the shape of the chip characterization. It was possible then to do a limited study by means of measuring tool park. During such a study, different models for chip formation became familiar, such as the Time or Merchant model. The aim of article is to gain insight into some accompanying phenomena, occurring while cutting of different materials and with various tools. During an experimental design, the possible effects of different variables on each other and individually were considered. Two work-pieces (C45, POM) with two inserts (with two different edge design) were tested while changing of cutting speed and feed. During measurements cutting forces at 5000 Hz signal reception were tested or the evolution of cutting temperature at different experimental settings was evaluated. The chip characteristics are measured by a high speed camera. The camera is connected with PC for recording and controlling the experimental procedure in real-time. The frequency of High Speed Camera was similar than the frequency of the cutting force measuring system. This similarity is provided with the system set-up synchronization.
EN
Self-reinforced SiAlON ceramic tool materials, due to its unique properties such as high wear resistance, high hardness and low affinity with metal, is widely used in machining nickel-based alloy. The self-reinforced SiAlON ceramic tool was used in the experimental process of high speed milling nickel-based alloy Inconel718. The results obtained through observing the tool wear morphology and further analysis showed that when cutting speed vc = 50–200 m/min, abrasive wear and lamellar spalling was the main cause of tool wear. When cutting speed vc = 350, 500 m/min, the bond strength between β-SiAlON whisker and SiAlON matrix reduced, and then the tool material fell off, which led to the formation of hole and groove. When the hole and groove mark connected, the crack nucleation formed. The crack propagation resulted in fracture eventually. At last, according to the tool wear mechanism, tool wear model was established and the optimal cutting temperature range, which can lead to minimum tool wear in milling Inconel718 using self-reinforced SiAlON ceramic tool, was obtained.
EN
The heat produced in metal cutting process has negative influence on the cutting tool and the machined part in many aspects. This paper deals with measurement of cutting temperature during single-point dry machining of the AISI 4140 steel, using an infrared camera. Various combinations of cutting parameters, i.e. cutting speed, feed rate and depth of cut lead to different values of the measured cutting temperature. Analysis of the measured data should explain the trends in temperature changes depending on changes in the cutting regimes. Furthermore, the temperature data is modelled using response surface methodology and fuzzy logic. The models obtained should determine the influence of cutting regimes on cutting temperature. The main objective is the reduction of cutting temperature, i.e. enabling metal cutting process in optimum conditions.
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