班級：碩研機械一甲
姓名：田正雨
學號： M9810213

• excellent hardness and very low frictional wear
• machine SD(Sintered diamond) with high precision by conventional methods such as cutting and grinding

• Since SD contains metal as binder , it is electrically conductive
• Micro-EDM, its ability to machine regardless of the hardness of the workpiece
• four types of SD, composed of 1, 3, 10 and 20 μm diamond particles

• Panasonic MG-ED72 micro-EDM machine, WEDG,
50μm-diameter cylindrical electrodes( tungsten )
• Binder (cobalt) , approximately 5%
• Tungsten carbide alloy was also tested for comparison

• Hole machining ：
• Discharge capacitance was 100 pF , and the opencircuit voltages were 100, 80, and 60 V
• measured the machining time , the electrode wear , and the side gap

• Trench machining ：
• The size of the trenches ： 50 μ m (width) × 4 mm
(length) × 30 μm (depth)
• 100v, 3300 pF( rough ), 100 pF( medium ) and stray capacitance(10pF, finish machining )
• surface roughness at the bottom of the trenches

Results and discussion _
Hole machining(1)
• Shape of machined holes ：
• There is no significant difference of size and roundness among all holes
• This fact suggests that precision and micro EDM of
SD is practical
Ø 50μ m, 100 V and 100 pF

Results and discussion _
Hole machining(2)
• Machining speed ：
• 20 μ m at 60 V and 80 V could not be machined ： electrode wear was so large
• Machining speed, SD and tungsten carbide alloy ： No significant difference Volmetric machining speed

Results and discussion _
Hole machining(3)
• Machining speed ：
• 100V 、 80V, machining speed apparently decreases ： debris
• The same phenomenon ： 3 μ m ,
BUT, 10 μ m and 20 μ m appears to be constant diamond particle ：
Debris influence ：

Results and discussion _
Hole machining(4)
• Electrode wear
• The wear ratio ： tungsten carbide < SD
• Machining speed ：
Electrode wear ：

Results and discussion _
Hole machining(5)
• Side gap
• There is no apparent correlation between diamond particle size and side gap

Results and discussion _
Trench machining(1)
• Surface roughness ： discharge capacitance ： the surface roughness ：

Results and discussion _
Trench machining(2)
• Observation of machined surface(By SEM) diamond particles are small ： can be removed diamond particles are large a part of particles craters
Same craters

• Round Ø 50 μ m micro holes were proved, 1–20 μ m
• Electrode wear ratio appeared to have a strong correlation with machining speed
• Side gap not have apparent correlation with diamond particle size .

• There is no significant difference in machining speed between SD and tungsten carbide
• A surface roughness of approximately 0.13 μ m
Ra was achieved for trench machining.