High-Speed Microfabrication Technique Using Focused Laser Beam

Abstract

A high-speed microfabrication technique using a focused laser beam was developed. A conventional CAD/CAM system was used, and the beam was scanned mechanically by attaching both optical mirror arrays and a focal lens to the column of an ultraprecision machining center. The measured groove width and pocket depth obtained by grooving and pocket machining were used as the tool diameter and the axial depth of cut, respectively. Glasslike carbon with a laser beam absorptivity of over 80% and a hardness of 650 MHv was employed as a workpiece. It was verified through a machining test that pseudo-3-dimensional concave prisms can be fabricated by digging square pockets with different square sizes but the same pocket depth in the negative Z direction. Shifting the laser's focal point away from the work surface can decrease the depth of the square pocket, so that high-speed roughing by adjusting the focal point on to the work surface and highspeed finishing by shifting the focal point away from the work surface can be conducted.