Effect of processing parameters on water penetration in water assisted injection
molding of ABS (in English)
Polimery 2011, No 3, 232
This study experimentally investigates the effect of processing parameters on water penetration and part hollow-core characteristics (includes wall thickness, core diameter) and shrinkage of the plastic molded part, in Water Assisted Injection Molding process (WAIM) of an amorphous polymer. WAIM has been developed for production of hollow plastic parts and is suitable for weight reduction of large parts with a good internal surface. Other benefits are fast cooling and short cycle time without compromising part quality. In this study acrylonitrile-butadiene-styrene (ABS) was chosen as the candidate amorphous polymer. The selected processing parameters were: water injection delay time, holding time and mold temperature. The mold cavity shaped a branched pipe (two-head) to be cored out via water penetration. Actual factory-like experiments and full shot size were applied during this research. The results showed that the longest water penetration, the least wall thickness differential, the highest uniformity in pipe diameter and the lowest shrinkage are obtained when the process parameters such as holding time and mold temperature are maintained at the highest level and delay time is optimized.