| 摘要: | 電化學加工（Electrochemical Machining，ECM），屬於非傳統加工方法的一種，以電解現象達成加工成形之目的，其優點為加工速度快、加工不受材料硬度限制、工件無表面應力殘留、工件無熱變質層之生成及表面粗糙度佳的優勢，具有相當的發展潛力與高附加價值。
本研究以灰色關聯分析作為分析工具，灰色關聯分析與常用的田口實驗法相比，其特點在於可以同時進行多重特性之評估，而田口實驗法一次只能望一品質。本實驗分為兩個部分：材料之選擇、以選擇的材料探討電化學加工參數（電解液流速、電解液濃度、刀具進給速率、操作電壓）對加工之材料移除率、表面粗糙度及過切量之影響趨勢。
第一部分以相同加工條件下對於兩種常用之模具鋼進行實驗，以選擇一較佳之材料，選擇的依據為材料移除率，其目的是為了減少能源之消耗，由結果可以得到，含碳量較高之材料會較難加工，若要達成相同目的會消耗更多的能源，因此選擇SKD61作為加工之材料。
第二部分以SKD61進行實驗，並由灰色關聯分析可以發現，影響球形孔加工最鉅的實驗參數為電解液濃度與操作電壓。球形孔之最佳參數組合為A3B2C2D3，即電解液流速3.98m/s、電解液濃度9 wt%、刀具進給速率0.2 mm/min與操作電壓15V。而加工之結果材料移除率為2.91 mm3/min、表面粗糙度 Ra為0.69μm與過切量為0.71 mm其平均誤差為2.0%，將其與初始條件相比其灰色關聯度從0.34提升到0.96，更加的接近本實驗之理想值。
;Electrochemical machining (ECM), which is one of the non-traditional manufacturing processes, shapes workpieces by electrolysis. The advantages of ECM include high processing speed, independent of metal properties, no surface residual stress, no heat zone, and smooth workpiece surface with enormous potentialities and highly added values.
In this study, grey relational analysis (GRA) is used as the analysis tool. Compared with Taguchi method, GRA could have multi-objective optimization, while Taguchi has only single-objective optimization. This study has two parts, and material selection is the first part. The second part of this research is to analyze the influences of parameters (e.g.: electrolyte flow rate, electrolyte concentration, the feed rate of the tool and applied voltage) on the material removal rate (MRR), surface roughness (SR), and overcut (OC) by GRA in the spherical hole machining by ECM.
At first part, two kinds of novel stainless steel are conducted under the same conditions for selecting the workpiece with higher removal rate material (MRR). The choosing basis is the MRR because a lower MRR means more energy should be used to have the same results. As the result, SKD61 is chosen as the working material.
In the second part, grey relational analysis (GRA) is used to analyze the optimal conditions for spherical hole machining on SKD61 by ECM. Results show that the most important factors are electrolyte concentration and applied voltage. And the best parameter combination simultaneously acquired from the research is A3B2C2D3(electrolyte flow rate 3.98 m/s, electrolyte concentration 9wt%, the feed rate of the tool 0.2mm/min and applied voltage 15V).The resulting material removal rate(MRR), surface roughness(SR) and overcut(OC) of machined specimenare2.92mm3/min, Ra 0.69μm,0.71mm and average error is 2.0% respectively. Compared with the original working condition (A1B1C1D1), the GRA is increased from 0.34 to 0.96. It is more closed to the ideal working condition. |
