CNC工具機之融合式機上溫升熱變形補償方法及系統研究

本研究主要在發展一套多軸溫升熱變形誤差補償系統，可減少工具機的主軸及伺服軸之熱變形誤差。研究中實驗變形量量測分為主軸與伺服軸兩部分，主軸用高精度接觸式定點判別型感測器量測機台主軸在X、 Y 、Z三方向之熱變形量，伺服軸使用雷射干涉儀量測X、 Y 、Z三軸之熱變形量。將所得主軸與伺服軸之溫度增加量與變化量，用多項式曲線擬合建立出主軸與伺服軸溫度增加量與變形量之熱變形迴歸方程式，進而利用Visual C#程式語言將方程式植入補償系統中，製作成機上溫升熱變形補償系統，此系統直接安裝於電腦上，可透過乙太網路與CNC控制器聯結。當工具機在切削時，通過系統即時擷取CNC控制器中的溫度資訊，系統將溫度代入迴歸模型計算出溫升熱變形量後進行補償，熱誤差補償分為主軸與伺服軸兩部分，主軸補償利用CNC控制器上之機械座標原點偏移功能進行線上補償，而伺服軸補償則是輸出補償指令以螺距誤差(Pitcherror)補償方式進行。研究中實驗溫度擷取使用PT100溫度感測器結合ADC(Analog-to-digital converter)擷取CNC機台上主軸及伺服軸各點的溫度，暫存在CNC控制器中，再利用系統透過乙太網路從CNC控制器擷取至電腦。實驗驗證結果顯示，本系統可改善熱變形70%以上，達到降低工具機熱變形誤差之目的。

關鍵字

熱變形；工具機；誤差補償

並列摘要

This study mainly developed an error compensation system which can be applied to reduce the thermal expansion error of the spindle of a CNC machine tool. Temperature variations at 5 locations on the spindle were measured by PT-100 thermal sensors and self-designed electric circuit, and the deviations of the spindle in x, y and z directions due to thermal expansion were measured by high precision displacement sensors. Based on the measured temperatures and deviations, a regression mathematic model was calculated and implanted into the PIC chip to form a system for on-line thermal expansion monitoring system. When a machine tool is working, PT100 sensors can on-line measure the temperature variations of the spindle and feedback to the monitoring system to predict the thermal expansion of the spindle. The predicted expansions are then outputted to CNC controller for error compensation through an optical coupling circuit. The experimental results have shown that the system can effectively reduced the thermal expansion error from 40m to less than 10 m.

並列關鍵字

thermal expansion ； machine tool ； error compensation

參考文獻

[17] 陳智豪，"CNC工具機之三軸熱變形誤差之監控與補償系統之研究"，中原大學碩士論文，2008。

[20] 蔡勝植， "滾珠導螺桿進給驅動系統的熱變形估測 "，國立台北科技大學碩士論文，2013。

[1] Moshe Barash,"Thermal Effects on the Accuracy of NumericallyControlled Machine Tools", Annals of the CIRP,Vol.35/1, 2000, pp. 255-258.

[2] Optiz,H.and R.Noppen,"A Finite Element Program System and its Application forMachine Tool Structural Analysis "MTDR,Vol.13,2001,pp.55-60.

[3] Bryan,J.,"International Status of Thermal Error Research", Annals of CIRP，Vol.392, 2002

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CNC工具機之融合式機上溫升熱變形補償方法及系統研究

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