| Summary: | 碩士 === 元智大學 === 機械工程學系 === 90 === In this research, the ElectroChemical Mechanical Polishing (ECMP) technology was established and the process parameters were studied for free-form surface polishing. The automatic polishing of free-form surfaces were accomplishing by integration the CNC machine center with the in-house ECMP set-ups. A laboratorial system with experimental apparatus and equipment was established. Several dedicated polishing heads were designed and prototyped. A series of fundamental electrochemical analyses and polishing experiments were conducted on die materials such as SKD 11, SKD 61 and SKH 9. These are materials widely used in the die/mold industry.
There were two sets of experiments, the electrochemical analyses and the ECMP polishing experiments. From the electrochemical analyses, the electrochemical parameters such as the type of electrolyte, the concentration of electrolyte and the current density were studied to obtain the best combination of parameters. Utilizing the optimal electrochemical parameters, the ECMP polishing experiments were conducted through Taguchi method of experimental design on flat test specimen of SKD 11, SKD 61 and SKH 9 die material. The current density, the spindle rotational speed, the pressure of the polishing head and the feed rate were the control parameters. Therefore, the optimal parameters for the ECMP polishing process were obtained from the variational and S/N ratio of Taguchi’s analyses.
Verification testes were conducted on a specimen with free-form surface. The special-design polishing head was clamped onto the spindle head of a CNC machine center. The polishing paths were generated from the CAM program. Using the ECMP technology, the surface roughness was reduced from 0.86 μm to 0.09 μm. It demonstrated that the ECMP technology could be an effective polishing method for automatic free-form surface polishing to achieve better surface quality.
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