13th International Conference on Fracture June 16–21, 2013, Beijing, China -1- Cutting Zone Temperature and Specific Cutting Energy Measurement and Evaluation in Machining Metals Y. Yifrach1, U. Ben-Hanan2 1 Department of Mechanical Engineering, ORT Braude College, P.O. Box 78, Karmiel 21982, Israel 2 Department of Mechanical Engineering, ORT Braude College, P.O. Box 78, Karmiel 21982, Israel Email: yifrach@braude.ac.il Abstract The knowledge of the temperature that develops between tools and the raw material is needed for optimizing the cutting parameters. A controlled Grinding experiment was compared with a thermo-mechanical finite elements model (FEM) simulating the temperature distributions and other effects occurring in the cutting zone. An electric Grinding was controlled by [Labview] software, keeping the torque and rotational speed constant and preventing disruption of fixed air flow. The processed material was glass ceramics, the mechanical and thermal properties of which are known from the literature. A finite elements model was developed and its parameters determined by matching the computed Nodes with thermocouples’ temperature measurements. The experiment was carried out by single slot cutting, without cooling. The value of cutting power was based on specific cutting energy (U), known from the literature and calculation of (MRR) from the cutting parameters (depth & width of cut, feed rate). The dynamic model simulated the movement of cutting tool by sampling heat sources along the path. The fit obtained between dynamic model and the measurements enables a reliable calculation of the specific cutting energy (U) for every combination of tool cut and raw material. Keywords: cutting, specific cutting energy (U), Material removal rate (MRR), finite element method (FEM). 1. Introduction Most of the energy of machining is transformed to heat. The heat transfer from the cutting zone depends on the heat capacity of the raw material and on its configuration. The temperature rise of the cutting zone may limit the cutting speed and cutting depth, causing tool wear and limiting its life, and creating thermal stress in the raw material and distortions of its surface. It is therefore highly desirable to measure the cutting zone temperature and relate it to the cutting performance parameters (depth of cut, cutting velocity, feed, linear speed of cutting progress, power required, Specific Grinding Energy). Due to the nature of metal cutting, it is not possible to measure temperature directly in the cutting zone. The main techniques used to evaluate the surface temperatures during machining are Thermocouple method and infrared photographic technique [1-4]. Two arrays of thermocouples were lined along both sides of the cutting path for measuring the temperature development throughout the working piece according to the drill’s advancement in recent years; the finite element method has particularly become the main tool for simulating metal cutting processes. It is especially important that FEM analysis can help to investigate the temperature distributions and other effects occurring in the
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