On-line Monitoring of Cutting Temperature with Microsensors
Date Issued
2014
Date
2014
Author(s)
Chang, Chia-Hao
Abstract
In metal cutting operation, there are still many difficulties in measuring cutting temperature, because the location of the maximum temperature occurs at the contact surface between the tool and the chip. Using an infrared thermal imager is susceptible to interference by chips or cutting fluid. If a thermocouple or thermistor is used, it is difficult to directly measure the tool tip temperature. Drilling a hole in the tool must be done, and it will increase costs. At the same time, cutting temperature is a good indicator for tool wear or tool condition monitoring.
In order to apply cutting temperature to monitoring in machining process monitoring, this study developed a novel temperature sensor for turning. It is a micro-thermistor made of NiO with a very high value of the thermal index B, so the resolution is very high compared to other types of temperature sensors. Moreover, miniaturized sensors can make multi-point temperature measurement within a small range possible. The tool tip temperature is estimated by the finite element method(FEM) with the measure temperature, which is known as inversed heat conduction problem(IHCP). In this study, the model order reduction(MOR) is used to increase computing speed of the FEM. In solving the IHCP, the conjugate gradient method is adopted to estimate the average temperature of the tip.
The results confirmed that the temperature sensor developed in this study can respond quickly to changes of cutting temperatures. In the non-cutting experiments, the average tool tip temperature can be accurately and quickly predicted with the micro-thermistor array and the conjugate gradient method with MOR. Finally, the proposed methodology is applied to estimate the tool tip temperature in turning.
Subjects
切削溫度
微感測器
精簡模型
Type
thesis
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