Method for molding two-piece blow molded hollow tank by using auxiliary male molds

A method for blow molding a hollow tank formed by two parisons by using auxiliary male molds, wherein the method comprises the following steps:

• 1) positioning the two parisons of the tank to be blow-molded into a mold, the mold comprising two half molds and a pre-molding template between the two half-molds, wherein the two parisons of the tank to be blow-molded are positioned between the two half molds and the pre-molding template respectively;
• 2) closing the two half molds of the mold onto the pre-molding template;
• 3) pre-stretching the molten parisons by using the auxiliary male molds provided on the pre-molding template;
• 4) performing high-pressure blow molding inside the mold to melt the two parisons, and pre-molding the molten parisons into two housing pieces;
• 5) opening the mold, and withdrawing the pre-molding template;
• 6) moving into the mold a device for facilitating inside components of the hollow tank to be connected to the pre-molded housing pieces;
• 7) moving the device out from the mold;
• 8) closing the mold for the second time and finishing blow molding the hollow tank;
• and
• 9) opening the mold and taking out the molded hollow tank;
• wherein the auxiliary male molds provided on the pre-molding template are set as a split-type structure which is merged together, and
• wherein step 3) further comprises the specific steps as follows:
• 3-1) when the two half molds, of the mold are closed onto the pre-molding template, the two half molds extrude the parisons to the auxiliary male molds provided on the pre-molding template, and after the parisons contact the auxiliary male molds, pre-stretching of the parisons is performed for a first time;
• and
• 3-2) after the two half molds are closed onto the pre-molding template, the parisons are sucked into the mold by vacuum force, and at the same time an actuating mechanism drives the auxiliary male molds to move toward an inner wall of the mold, so as to perform pre-stretching on the parisons for a second time;
• and
• wherein in the step 6, a robot moves the device together with the inside components to a location that is between the two half molds and where the connection of the inside component to the pre-molded housing pieces shall be performed.