Injection mold apparatus for pressure vessel

A method of controlling an injection mold apparatus including an upper mold including an internal surface in a shape corresponding to a shape of an external surface of a pressure vessel provided with a nozzle with a closed inlet, a lower mold including an external surface in a shape corresponding to the shape of the internal surface of the pressure vessel, engaged with the upper mold, formed with a cavity for injection of the pressure vessel between the upper mold and the lower mold, and formed with an air injection passage therein, an ejector fluidically communicating with the air injection passage of the lower mold and injecting air through the air injection passage between the lower mold and the pressure vessel, and an air injection rate setting device, the method comprising:

• adjusting, by a controller, a pressure of the air injected between the lower mold and the pressure vessel by controlling the air injection rate setting device according to a distance difference between a distance between an external surface of a nozzle receiving recess and an end portion of the nozzle and a distance between an end portion of the lower mold and an end portion of the pressure vessel;
• measuring, by a first distance measuring device, the distance between the external surface of the nozzle receiving recess and the end portion of the nozzle, and measuring, by a second distance measuring device, the distance between the end portion of the lower mold and the end portion of the pressure vessel;
• and
• closing the air injection rate setting device, by the controller, or, adjusting a degree of opening of the air injection rate setting device, by the controller, based on the distance measured by the first distance measuring device and the distance measured by the second distance measuring device.