Product Code: ICAL07_1106

Laser Heat Sealing of the Polymer Coated Steel Sheet
Authors:
Tatsuhiko Sakai, Nippon Steel; Futtsu, Chiba Japan
Hirofumi Imai, Nippon Steel; Futtsu, Chiba Japan
Hirokazu Yokoya, Nippon Steel; Futtsu, Chiba Japan
Hiroshi Nishida, Nippon Steel; Futtsu, Chiba Japan
Naoya Hamada, Nippon Steel; Futtsu, Chiba Japan
Presented at ICALEO 2007

The polymer coated thin steel sheet is used for materials for electronics and building applications. At least two steel sheets are joined by tight rolling at their edge for the materials processing. The edge of the steel sheet is needed to be wrapped inside the joint roll and be sufficiently sealed off against the environment to prevent rusting. In this study, we developed the laser heat sealing of joint roll. The joint roll was sufficiently sealed off by melting of polymer at its adjacent area. The influence of processing parameters such as laser power density, beam scanning speed and wavelength was examined using the PET film coated (Ni plated) steel sheet. The wavelength tunable CW CO2 laser was employed as a light source. We obtained the good sealing results using the 10.59μm at 10P(20) line, where it shows relatively low absorption in PET. The irradiation at 9.27μm at 9R(20) line, where it shows strong absorption, resulted in the burning and carbonization of polymer. It is understood that the laser energy transmitting through the PET heated the steel substrate and it contributed to the moderate melting of the PET for the former case. By optimizing the laser parameters, rusting in the joint roll was successfully prevented. The processing speed reached 0.5m/s with the laser power of 60W. The detailed laser sealing characteristics will be discussed in the presentation.