关键词: 钻针, 脉冲磁场处理, 硬质合金, 印刷电路板, 磨损

Abstract: In order to improve the boring performance of the cemented carbide drill bit, pulsed magnetic field treatment was adopted to treat the drill bits with the diameter of 0.5 mm under the processing parameters of 0-2T. The drilling experiments were carried out on the printed circuit board, and the wear, drilling quality, microstructure and mechanical properties of the treated cemented carbide drill bits are characterized respectively. The results show that after drilling 4 000 and 12 000 bores, the wear area of the treated drill bit is significantly reduced. In particular, the wear area is reduced by 37.97% when 1 T parameter is used to drill 4000 bores while that is reduced by 38% when 2 T parameter is adopted to obtain 12 000 bores. The diameter of the bores obtained by the pulsed magnetic field treated drill bit varies relatively small, with the diameter range of 0.47-0.5 mm, compared to that gained by the untreated drill bits， with the diameter range of 0.44-0.49 mm. When 1.5 T parameter is used， the roughness of the bore is reduced by 42%, which shows significantly improved surface quality of the wall of the bore. The hardness and the elastic modulus are enhanced by 26%-116% and 40%-312% respectively after the pulsed magnetic field treatment, and they exhibit an increasing tendency with the increasing strength of the field. The improved boring performance and the mechanical properties are attributed to the multiplication of the defects induced by the pulsed magnetic field.

Key words: drill bit, pulsed magnetic field treatment, cemented carbides, printed circuit board, wear