| 摘要 |
A method of injection moulding for use with an injection moulding machine (10) includes: (a) generating pressurized gas and pressurized moisture within molten plastic as plastic pellets are plasticized in the injection moulding machine (10), the pressurized gas and the pressurized moisture having a total pressure defining an internal counterpressure within the molten plastic; (b) pressuring air within a cavity (30) of a mold (22) in the injection molding machine (10) to an air pressure level which is substantially equal to the internal counterpressure in order to counterbalance the internal counterpressure as the moulton plastic is injected into the cavity (30), thus providing a substantially pressure balanced molding environment for the plastic; and (c) maintaining the air pressure level in the cavity (30) substantially constant as the molten plastic is injected into the cavity (30). A mold apparatus for use with the method of injection molding includes selectively sealed venting of the mold cavity (30), the vents (42) being configured to maintain a substantially constant air pressure within the cavity (30) as the cavity (30) is filled with molten plastic. <IMAGE> |
