班級：碩研機械一甲 姓名：田正雨 學號： M Micro-EDM of sintered diamond

excellent hardness and very low frictional wear machine SD(Sintered diamond) with high precision by conventional methods such as cutting and grinding Introduction(1/2)

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 Introduction(2/2)

Panasonic MG-ED72 micro-EDM machine, WEDG, 50μm-diameter cylindrical electrodes(tungsten) Binder (cobalt), approximately 5% Tungsten carbide alloy was also tested for comparison Experiments(1/3)

Hole machining ： Discharge capacitance was 100 pF, and the open- circuit voltages were 100, 80, and 60 V measured the machining time, the electrode wear, and the side gap Experiments(2/3)

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 Experiments(3/3)

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 Results and discussion _ Hole machining(1) Ø 50μ m, 100 V and 100 pF

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 Results and discussion _ Hole machining(2) Volmetric machining speed

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 Results and discussion _ Hole machining(3) diamond particle ： Debris influence ：

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

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

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

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

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. Conclusions(1/2)

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. Conclusions(2/2)