Papers by Author: Yi Chwen Lee

Abstract: Dendrite needles grow from an undercooled melt and their shapes depend on the temperature distribution on the solidification front, which are specified by some parameters such as undercooling, capillary length, diffusivity, convection and kinetic effects. Neglecting the convection and kinetic effects, this study numerically computes the quasi-steady-state integral-differential equation to obtain the shape of a dendrite using solvability condition and investigates the effect of parameters changing the temperature field on the shape of a dendrite. The results reveal that the tip shape enlarges with the decreasing undercooling and increasing capillary length. On the other hand, the increase of thermal diffusivity only slightly reduces the tip radius and shape of a dendrite.

Abstract: This paper utilized a wireless temperature sensing system to measure the temperature histories of tool and workpiece during cutting. It is essential to use a wireless sensing system to measure the temperature in cutting and monitor the cutting process due to tool movement, workpiece turning, network monitoring and safety consideration. The temperature sensing system includes the wireless transmitter and receiver, A/D and D/A converter, data processing software, and computer. The temperature histories for different feed rates and depths of cut were measured in real time during cutting. The data measured by using wireless temperature sensing system were also compared with these obtained from an infrared thermometer.