Soya Takagi

Phenomenological Studies in Laser Cladding. Part I. Time-Resolved Measurements of the Absorptivity of Metal Powder

Time-resolved measurements were introduced to study the dynamic behavior of the absorptivity of metal powder under CO2 laser irradiation conditions. The absorptivity of metal powder was more than 90% under short-term laser irradiation (6-20 ms), but it was below 30% under relatively long-term laser irradiation (50-1000 ms). The experimental results propose that the dynamic change of the absorptivity is caused by time-dependent aggregation of powder particles induced by laser irradiation.

Phenomenological Studies in Laser Cladding. Part II. Thermometrical Experiments on the Melt Pool

A novel two-color pyrometer composed of a high-speed shutter TV camera and an image intensifier is employed to study the surface temperatures of the cladding layer under CO2 laser radiation. The two dimensional image of the surface temperature of the melt pool was stored in the frame memory in National Television System Committee (NTSC) formula. Also, high-speed photography was used to observe the dynamic behavior of the melt pool. The rapid motion and temperature change of the melt pool were observed and the former was greater than the laser scan (200 Hz). From these two time-resolved measurements, the laser cladding layer was found to be under the control of the dynamic behavior of the melt pool.

Applications Of Laser Processing For Automotive Manufacturing In Japan

Recently in Japan, laser processing is increasingly being employed for production, so that laser cutting, laser welding and other laser material processing have begun to be used in various industries. As a result, the number of lasers sold has been increasing year by year in Japan. In the Japanese automotive industry, a number applications have been introduced in laboratories and production lines. In this paper, several current instances of such laser applications will be introduced. In the case of welding, studies have been conducted on applying laser welding to automatic transmission components, in place of electron beam welding. Another example of application, the combination of lasers and robots to form highly flexible manufacturing systems, has been adopted for trimming steel panel and plastic components.