運用實驗設計法探討製程因子－－以CNC加工機為例

A Study of the Use of Experimental Design Process Factors for CNC Machine Case

本研究主要以電腦數值控制（Computer Numerical Control, CNC）銑床為範例，運用實驗設計法探討製程因子之最佳化。由於會影響CNC銑床製程結果的因子含主軸轉速、進給率、切削深度、刀具的選用及冷卻液之選擇等，故本研究利用IDEF（Integration DEFinition for Function modeling）建模方式將製程因子做適當的篩選，最後選定主軸轉速與進給率作為實驗因子，並藉由實驗設計（Design of Experiments, DOE）以及反應曲面法（Response Surface Method, RSM）等方法，將加工時間、換刀時間等反應變數作為限制，使其製程參數在限制範圍中達到要求，並在每個反應變數下所建立之反應曲面模型中找到最佳的製程條件，意為應用DOE中的RSM再加上中央組合設計（Central Composite Design, CCD），以找出對CNC銑床的最佳製程條件。由於本實驗的反應變數為不同的CNC銑床參數，主要是以主軸轉速與進給率下所形成的加工時間與銑刀換刀時間，故實驗將藉由迴歸分析（regression analysis）之方程式描述以得知兩變數間關係。

Due to this research uses rigid material, it would consume much more cutter. Based on CNC (Computer Numerical Control) milling machine as an example, this research would explore the optimization process factors by experimental design. There are many factors would affect the result of CNC process which including CNC spindle speed, feed rate, cutting depth, selection and the selection for the tool coolant and etc.; therefore, this research will make the appropriate choosing for process factors by using the IDEF ( Integration DEFinition for Function modeling) model. This research decides to use the spindle speed and feed rate as the experimental factors; based on DOE (Design of Experiments) and RSM (Response Surface Method) methods, adopting the processing time and switching tools timing as the response variables; therefore, the process parameter could reach the requirement under the limit scope. Besides, it could discover the best process condition by each response variables under the construction of the response surface model. It means applying RSM of DOE and adds CCD (Central Composite Design) to find out the optimal process conditions of CNC milling machine. Due to the response variable of this experimental are different, CNC milling machine parameters which formed by spindle speed and feed rate of process timing and changing timing for milling tools. Therefore, this research would use the regression equation to analyze and explain the relationship between two variables.