Characteristic of micro-hole drilling on Polycrystalline Diamond by micro-EDM technique using nickel powder suspension dielectric oil

• Main Authors: Han-Yu Wu, 吳涵玉
• Other Authors: Tzu-Yao Tai
• Format: Others
• Language: zh-TW
• Published: 101
• Online Access: http://ndltd.ncl.edu.tw/handle/30618164273426771965

碩士 === 南台科技大學 === 機械工程系 === 100 === Polycrystalline diamond (PCD) has high hardness、high strength、high thermal conductivity、and abrasion resistance. In recent years, it is a material widely used in the industrial production. This study investigates the addition of nickel powder into EDM dielectric on micro-hole machining of polycrystalline diamond by using tungsten carbide electrode. Compare addition powder and no addition with that into the dielectric.The addition of nickel powder into EDM dielectric that particles had 50nm, 85nm and 1 ~ 3μm of 3 kind of nickel powder and 0.7g / l,3.9g /, l、 7.0g / l ,of 3 kind of concentration. The peak current is 0.1A, 0.5A, 1A, 2A , the voltage is 160V. It is expected to accelerate the material removal rate. Thereby, the impact of particle size of nickel powder, nickel powder concentration and discharge parameters for the polycrystalline diamond surface characteristics is explored. Experimental results show that the powder concentration increases leading to increase the material removal rate significantly. As for the material removal rate has the best inhibition results that particle size 50nm. Due to the smaller particle size, powder is more easily into the discharge gap as bridging role and increases the material removal rate as consequence.But that powder 50nm smaller particle size, instead caused the powder can into the bottom of the hole,so that discharge gap on the bottom of the hole would be bigger,and the bottom of blind hole contour deformation,then the powder particle size of 85nm in the discharge gap volume would be more medium can also retain the bottom of the hole contour. Moreover, powder mixed addition into the dielectric of concentration, electrode wear rate and surface roughness reduce due to increase of powder concentration which powder concentration of 7g/l has inhibit electrode wear rate. It follows from what has been said that particle size of 85nm, concentration of 7g / l, that accord this experimental of demand. The result of this study show that the powder enabling efficient processing and brought to the expansion aperture that the lead to the appearance of holes in the contour deformation. In order to enhance the contour,the powder should be added to improve the the processing efficiency in the EDM dielectric. Furthermore,reducing the electrode size can retain its precision,Therefore also can considerable improve the processing of polycrystalline diamond micro-hole machinind efficiency.