Alireza Babaei

Real-Time Tool Wear Monitoring Based on Feed Motor Current in Chuck-Center Mounting Condition

On-line tool wear condition monitoring is a significant area of research in automated machining process. This study concerns the development of an on-line tool wear condition monitoring system based on a fuzzy logic scheme. The feed motor current was measured and used as the input of a fuzzy process. Previously, most studies in this field have assumed the workpiece as rigid. However, in practice, cutting force causes the elastic deflection on workpiece and changes actual cutting depth. Therefore, due to coupling between actual depth of cut and feed motor current, the measured current values vary on cutting length according to workpiece elastic deflection pattern. This oscillation in current signal which is used as the input of monitoring system, can affect output results. Thus, in this study in order to achieve more accurate results, the workpiece clamping condition has been considered and through monitoring software a correction factor has been applied on outputs. Experimental results indicate that the proposed method can be reliable for practical applications of tool monitoring systems.

Investigation of Grinding Surface Temperature: Experimental Measurements and Numerical Modeling

Main restriction for achievable material removing rate and simultaneously high quality parts in grinding process is the high specific energy requirements and consequently thermal damage to workpiece. In this work, a sequence of experimental tests were performed focused on grinding parameters including wheel speed, workpiece feed rate and depth of cut. Previously developed grindiable thermocouples were utilized to measure grinding surface temperature in each experiment. Feasibility of the grindable thermocouples in workpiece surface temperature measurement in the grinding process was investigated. Then, a 2-D finite element thermal model was created using ANSYS code based on the experimental data for numerical investigation. The model was used to predict grinding surface temperature in conditions of the experiments. A comparison between experimental and numerically predicted results for grinding surface temperature shows good agreements within an acceptable margin of error. The absolute average of errors is equal to 6.6%. Therefore, the proposed grindable thermocouple technique can be used in measurement of workpiece surface temperature and study of thermal aspects of grinding process.