Warm Microforming Using a Laser-Driven Flyer
H-X. Liu, J-W. Li, Q. Zhang, Z-B. Shen, Q. Qian, H-F. Zhang and X. Wang
Microforming using a laser-driven flyer has been applied to manufacture microparts for its high efficiency, low fabrication cost and good product accuracy. To obtain an improvement in formability, in this paper, warm microforming by laser-driven flyer is studied. The effects of temperature, rubber pad and laser energy on formability are extensively investigated. Then, experiments using pure Cu with thickness of 50 μm are carried out in a semi-die at the temperature of 25, 100 ºC and under the laser energy of 1020, 1380, 1690, 1800 and 2000 mJ, respectively. Aiming at characterizing the microformability, the key factors including both forming depth and filling capability are discussed quantitatively; consequently, it can be demonstrated that the forming depth, assisted by a flexible rubber, reaches up to 168 μm at 100 ºC, which improves 16% compared to cold forming. It is also found that the depth increases with the increasing of laser energy and filling capability is improved at 100 ºC, attributing to the reduction of heterogeneous deformation. Besides, it is also found that the reinforced microformability benefits a lot from the aid of silicon rubber pads, which have the advantage of homogenizing and magnifying shockwave pressure, decreasing oxidation as well avoiding serious failure as a separation layer.
Keywords: Nd:YAG laser, copper, silicon rubber pad, laser-driven flyer, warm microforming, laser shock forming