Large Area Micro-texture Imprinting onto Metallic Sheet via CNC Stamping

Abstract

Micro-lens array and micro optical elements require for geometrically accurate registration of micro-patterns onto the oxide glasses. Heat radiation device and heat reservoir units have to equip their own unique micro-patterns with high aspect ratio. Lithography and related processes, or, micro- and nano-imprinting are effective to make these micro-patterns once onto the silicon or silica substrates. Even in those applications, the aspect ratio of micro-patterns is still limited to be shallow. The authors have been developing a new method to fabricate a DLC (Diamond-Like Carbon) coated mother mold-die by plasma oxygen etching and to duplicate the original micro-patterns on the mold-die onto the metallic and plastic sheets. This approach is suitable not only to mass-production of micro-patterned sensors and devices but also to selective nano- and micro-imprinting of various micro-patterns onto the metallic sheets. In the present paper, a micro-cavity pattern with the unit size of 3.5x3.5x4.6μm3 is imprinted onto an aluminum sheet with the thickness of 0.08mm by CNC-stamping with use of the micro-textured DLC-die. This CNC-stamping system is revised to make motion control both in loading and unloading processes for improvement of geometric accuracy and increase of aspect ratio in the micro-cavity pattern. Among several motion-control programs, a pulse-wise motion is employed to duplicate the deeper micro-cavity patterns onto the aluminum sheets.