Abstract: This report investigated the effect of melt temperature on the water penetration behavior in water-assisted injection molding process by using visualization technology. Experiments were carried out with the help of a newly home-developed water injection system and visual mold. The material used was polystyrene. The water-assisted melt filling processes with different melt temperatures were observed. It was found that low melt temperatures increased the melt inertia in the front of water flow, which leaded to the appearance of a water channel in broken lines. The rate of water front was closer to that of water-front melt. The time for water jet penetration and water penetration in the front half mold, increased with increasing melt temperature.

Key words: water-assisted injection molding, melt temperature, water penetration behavior, visualization