研究生：王郁涵指導教授：戴子堯

報告日期 :2015/05/25

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(微細放電加工因脈衝功率條件對加工的影響 )

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Outline

1. Introduction2. EDM parameter3. Experimental equipment and conditions4. Results5. Conclusions

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1. Introduction

• The pulse condition is particularly focused on the pulse duration and the ratio of on-time to off-time, and the machining properties are reported on tool wear, material removal rate,

and machining quality.

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2.EDM parameter

• E = VIT - (1)V:電壓， I:電流， T:時間 (s)

• EP = -(2) :單發脈衝的電壓， :單發脈衝的電流， :脈衝持續時間， :脈衝持續時間

• MRR = -(3)固定的材料去除， :單發脈衝的電壓， :單發脈衝的電流， :脈衝持續時間， :脈衝持續時間

放電能量

放電能量頻率

材料切除率

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2. Experimental equipment and conditions

(光學測量裝置 )

(電極 )

(主軸電機 )

Fig. 1. Schematic diagram of desk-top machine tool.

前視圖 右側視圖

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• The tool electrode is tungsten rod of 0.3mm diameter and the workpiece is SUS304 sheet of 1 mm, machining of slot with 0.5mm depth .

(電極 ) (碳化鎢 )

(工件材料 )

(電晶體 )(電路 )

(供電電壓 )(供電電流 )

(脈衝持續時間 )

(主軸轉速 )

(絕緣液 )

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4.Results

Fig. 2. Material removal and tool wear rate vs. EDM pulse voltage.

(材質去除率 )

(刀具磨損率 )

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Fig. 3. Material removal and tool wear rate vs. EDM pulse current.

(刀具磨損率 )

(材質去除率 )

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Fig. 4. Gap distance between a tool and a machined surface: (a) Gap distance between a tool and a

machined surface.(b) Result for the voltage parameter.(c ) Result for the current parameter.

輸入電壓

輸入電流

俯視圖 側視圖

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Fig. 5. Material removal rate vs. On–Off time conditions of EDM pulse.

Parameters of pulse duration and – ratio

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Fig. 6. Tool wear rate vs. On–Off time conditions of EDM pulse.

(脈衝持續時間 )

(磨損率 )

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5. Conclusions

• The parameters were selected from the simple equation for the material removal rate and the experiments have been carried out for various

EDM pulse conditions.

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• (1) Voltage, current, and pulse on/off time of the EDM power are main parameters to make decision of the material removal rate. Voltage and current are proportional to the material removal rate. On the contrary, current is only proportional in the case of tool wear rate.

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• (2) In the measurement of the gap between a tool and a machined surface, it is increased with an increase of voltage and current. But it is inversely proportional to the length of

pulse-on time.

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• (3) The duration of pulse on/off time considerably affects machining properties such as material removal rate, tool wear rate, and machining accuracy.A comparatively shorter pulse on duration is profitable to make accurate machining with a higher removal rate

and a lower tool wear rate.