Cooling of a Preform Mold in a Two-Stage Manufacturing Process for Plastics Bottles

• Main Authors: Chien-Ming Chen, 陳建銘
• Other Authors: Jung-Yang San
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/84934936382649990254

碩士 === 國立中興大學 === 機械工程學系 === 89 === This work deals with an experimental measurement and a heat transfer analysis of the cooling process in the injection molding of a preform. The tip of the plunger is cooled by using the technique of water jet impingement. The preform is the intermediate product in manufacturing a plastics bottle. A preform mold is designed and manufactured. The effects of plastics melting temperature , coolant temperature and coolant flowrate on the cooling time are investigated. A low density polyethylene (LDPE) is used in the experiment. A numerical analysis using the Gauss-Seidel iteration scheme is performed for the cooling process. Two plastics materials are considered. One is the low density polyethylene (LDPE) and the other is a polyethylene terephthalate (PET). The obtained cooling time matches well with the measured data. Two plastics melting temperatures ( 175℃ and 165℃ ), two cooling water temperatures ( 5.5℃ and 26℃ ) and two sets of cooling water flowrate ( 4.2 and 0.6 l/min individually for plunger, 0.71 and 0.37 l/min individually for cavity mold) are individually considered. It is found that the cooling of the plunger is the most important factor determining the mold production rate.