ALTERNATIVE PRESSURE CONTROL FOR A LOW CONSTANT PRESSURE INJECTION MOLDING APPARATUS

摘要

A melt pressure regulating mechanism for an injection molding apparatus having a melt holder for pressurizing molten plastic prior to injection into a mold, the molten plastic having a melt pressure, and an injection element for advancing the molten plastic from the melt holder into the mold, the melt pressure regulating mechanism comprising: a pressure regulating device disposed between the melt holder and the mold, the pressure regulating device maintaining a substantially constant melt pressure within a mold cavity, the pressure regulating device comprising one of a fluid pressure regulating valve and a pressure relief valve. The injection molding machine forms molded parts by injecting molten thermoplastic material into a mold cavity at low constant pressures of 6,000 psi and lower.