this invention is in the form of automatic molding device and molding method for the molding of the opening. according to the invention, according to the communist party of china plastic products molding device of plastic products to the work of the ministry and half in the cavity (20a). the formation of the weld forming part of the projection (20bb) have a projection (20b) have a horizontal mobile. "20); the horizontal removable die (20) to the left. try to make at least two first slide the cylinder (24) is equipped with, at least, one side of the pool. it is (21a) and contact the molten resin supply is the injection molding machine (25) is assigned a fixed pattern (21) and the delay in the uc218ud3c9uc774. die (20) and the face,. on the side of the cavity (20a), the weld forming part of the projection (22aa) with the corresponding projection (22a) and other side is equipped with the projection (20b), the other half of the ministry of plastic products, in order to deal with the cavity (22b the vertical) to form a removable die (22); a the primary body (27) and the second slide the cylinder (28) and the third slide the cylinder (29), and transfer means (31), with a shift pattern (23) and a delay in the injection molding machine (25), the first, the second and the third slide (24, 28, and the cylinder 29), connected to the fixed electric uc801uc73cub85c plastic operation. in the control task as soon as possible to include as features.