工具機刀具之即時切削溫度量測方法

Abstract

切削溫度是機械加工中的重要因素，直接影響了加工精度，如加劇刀具磨耗量、使刀具產生熱伸長與降低工件表面的精度；因此，切削溫度的量測對於加工精度的最佳化非常重要。然而，受限於主軸的高速旋轉，切削溫度難以使用有線的方式測量；刀具與工件的斷續接觸也使得切削刃表面無法直接架設感測器。為克服量測上的障礙，本研究開發了一個可以裝設在刀把上的溫度量測模組。使用K型熱電偶作為溫度感測器，量測可拋棄式刀片與切削刀具刀桿之間的位置。熱電偶線透過鎖固刀片的螺絲產生的夾持力固定，量測的溫度資料透過藍芽模組傳輸到電腦端以實現實時的切削溫度量測。量測模組被用於實際切削實驗中進行溫度的量測並與熱像儀進行比較。結果表明，在銑削中碳鋼S50C時的穩態溫度為150-200°C。溫度量測模組具有相當程度的重複性，並且在量測銑削過程中的穩態溫度時，溫度感測模組具有一定的準確性。然而，由於溫度量測點與產生高熱的切削刃具有一段距離。因此，本研究將量測所得的溫度資料進行模擬，逆向運算出加工過程中輸入至刀具中的熱量，並進一步建立出刀具隨時間的溫度場分布。根據模擬結果表明，刀尖點的溫度最高會到達208度。

Cutting temperature is an important factor in mechanical machining. It directly affects machining accuracy, such as increased tool wear, thermal deformation of the tool, and decreased surface accuracy of the workpiece. Therefore, accurate measurement of cutting temperature is crucial for optimizing machining precision. However, limit by the high-speed rotation of the spindle, it is hard to measure cutting temperature through wire connection. Additionally, intermittent contact between the tool and the workpiece makes it difficult to directly install sensors on the cutting-edge surface. To overcome these measurement obstacles, this study developed a temperature measurement module which can be attached on the tool holder. K-type thermocouple is used as the temperature sensor, measuring the position between the disposable cutting inserts and the tool shank. The thermocouple wires are clamped with the clamping force generated by fastening the screws which is used to fix the cutting inserts. The measured temperature data was transmitted to the computer in real-time via a Bluetooth module to achieve real-time cutting temperature measurement. The measurement module was used in actual cutting experiments to measure the temperature and compare with the thermography. The results show that the steady-state temperature during milling of S50C carbon steel ranged from 150-200°C. The temperature measurement module demonstrated a certain degree of repeatability. And during the measurement of the steady-state temperature in the milling process, the temperature measurement module demonstrates a certain degree of accuracy. However, due to the distance between the temperature measurement position and the cutting edge where heat is generated, the measured temperature data is used for simulation to inverse calculate the heat flows into the cutting tool during the machining process. Moreover, a temperature field distribution of the tool over time is established. According to the simulation results, the highest temperature at the cutting tool edge can reach 208°C.