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(微細放電加工因脈衝功率條件對加工的影響)
研究生：王郁涵
指導教授：戴子堯
報告日期:2015/05/25
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Outline
1.
2.
3.
4.
5.
Introduction
EDM parameter
Experimental equipment and conditions
Results
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)
放電能量
V:電壓，I:電流，T:時間(s)
• EP =
1
V𝑝 𝐼𝑝 𝑡𝑜𝑛
𝑡𝑜𝑛 +𝑡𝑜𝑓𝑓
-(2)
放電能量頻率
V𝑝 :單發脈衝的電壓，𝐼𝑝 :單發脈衝的電流，𝑡𝑜𝑛 :脈衝持續時間，𝑡𝑜𝑛 :脈衝持續時間
• MRR =
1
𝛼V𝑝 𝐼𝑝 𝑡𝑜𝑛
𝑡𝑜𝑛 +𝑡𝑜𝑓𝑓
-(3)
材料切除率
𝛼:固定的材料去除，V𝑝 :單發脈衝的電壓，𝐼𝑝 :單發脈衝的電流，𝑡𝑜𝑛 :脈衝持續時間，𝑡𝑜𝑛 :脈
衝持續時間
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2. Experimental equipment and conditions
(主軸電機)
(電極)
(光學測量裝置)
前視圖
右側視圖
Fig. 1. Schematic diagram of desk-top machine tool.
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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)
(電路)
(電晶體)
(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
(材質去除率)
(刀具磨損率)
Fig. 2. Material removal and tool wear rate vs. EDM pulse voltage.
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(材質去除率)
(刀具磨損率)
Fig. 3. Material removal and tool wear rate vs. EDM pulse current.
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俯視圖
輸
入
電
壓
側視圖
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
流
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Parameters of pulse duration and 𝑡𝑜𝑛 –𝑡𝑜𝑓𝑓 ratio
Fig. 5. Material removal rate vs. On–Off time conditions of EDM pulse.
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(磨損率)
(脈衝持續時間)
Fig. 6. Tool wear rate vs. On–Off time conditions of EDM pulse.
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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.
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