| 摘要 |
PROBLEM TO BE SOLVED: To achieve reduction in machining cost of a die, improved durability of a device, and high manufacturing efficiencies when a hollow molded item is manufactured by a gas-aided injection molding method. SOLUTION: While a molten synthetic resin R is being injected into a cavity 13, gas is blown off from nozzles 17, 18, 19 in the order of increasing distance from an injection port 15 to inject the resin R in an expanded form. Even if the pressure of the gas is relatively low, e.g. 20-30 kg/cm<2> , the resin R can be molded into a hollow shape easily and surely, and hence manufacturing and maintenance costs of device can be reduced and durability and manufacturing efficiency can be improved. |
