| dc.description.abstract |
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. | en_US |