Fabrication of Large Aspect Ratio PCD Micro-milling Tool with Pulsed Lasers and Grinding

Abstract

Abstract Micro-milling tools greatly affect the surface quality and machining accuracy in the milling of the high-aspect-ratio microstructures. Polycrystalline diamond (PCD) micro-milling tools have superior performance than traditional carbide tools. However, the fabrication of the large aspect ratio PCD tool is a problem on account of its low stiffness and high hardness. Present study proposed a compound processing method, combining pulsed nanosecond laser, picosecond laser with precision grinding, to manufacture a designed large aspect ratio PCD micro-milling tool with 3/4 body efficiently and accurately. The nanosecond laser was used to remove the allowance quickly, then the grinding was employed to treat the rake face, and the picosecond laser was applied to make the cutting edges. The influence of the picosecond laser parameters on tool surface quality and cutting edge radius were investigated and an optimal PCD tool was fabricated. Then the machining performance of the fabricated PCD tool was compared with commercial cemented carbide tool in surface roughness, milling force and tool wear by micro-milling tests. Experimental results showed that the surface quality of the laser-treated PCD rake face is improved after grinding whose roughness is less than 1 μm. The surface morphology and radius of the picosecond laser-treated cutting edge are heavily dependent on the laser experiment conditions. The large aspect ratio PCD tool with a diameter of 0.5 mm, length-diameter ratio of 3 and cutting edge radius of 3.5 μm was obtained by using the optimal parameters. The micro-milling tests demonstrated that the fabricated PCD tool had predominant performance when milling the deep-narrow-grooves.