Abstract
The microforming of surface cavities is a promising method of creating a functional surface on a metal workpiece. In a previous report, basic ideas on a method for and characteristics of metal-formed surface cavities as information transmitters were described. In this study, for small samples or small areas for storing information, the possibility of miniaturizing surface cavities is explored in terms of metal forming and the decoding of the 2D bar code with a PC-based optical measuring system. Dots with a 16-fold higher density of 840 DPI and a pitch of 30 μm on a mirror-finished metal plate were successfully metal-formed and decoded. The limitation of the miniaturization was the need to limit the diameter of surface cavities within 120% of the pitch of the dots. In addition, the effect of the surface roughness of the workpiece was examined to confirm the applicability of this method. Hairline-finished or abraded test pieces were successfully decoded with an enhanced inclination of lighting angles and/or additional image processing for enhancing the optical contrast between the background and the dotted cavities.
