关键词: 碎纸机, 热流道, 注塑模具, 抽芯机构, 模具排气, 水路设计

Abstract: Taking the plastic shell of paper shredder as the research object， a large hot runner plastic mold with a complex structure was designed. According to the structural characteristics of the plastic parts and the requirement of use， a two-hot-nozzle-feeding mode was designed in the mold to ensure the balance of feeding. A sliding block core-pulling mechanism of female die tunnel driven by an oil cylinder， a sliding block core pulling mechanism driven by an overhead cylinder， a sliding block core-pulling mechanism driven by a ground side-inclined pin together with a time-delay elastic pin， and five inclined pin core-pulling mechanisms were designed. These designs solved the demolding problem in all of inverted plastic parts. A U-shaped waterway was designed for the female die. The uniform distribution way for water wells was adopted for the male die， and the water-cooling system on the slider was separately designed. With such designs， the mold exhibited excellent performance in the molding cycle and quality of plastic parts in the actual production process. The die ejection was mainly completed by a declined pin core-pulling mechanism and a straight ejecting mechanism.

Key words: paper shredder, hot runner, injection mold, core-pulling mechanism, mold exhaust, waterway design