The ejection of plastic products is the last step in the plastic injection molding process. The quality of components such as straight ejector pin in the ejector system determines the quality of plastic products. When the mold is opened, the plastic article must be held on the mold half (usually the core) by an ejector mechanism for releasing the plastic article.

1. Thimble design principles:

    (1) In order to prevent plastic products from being deformed during ejection, the ejection force must be distributed as evenly as possible, and as close as possible to the core or parts that are difficult to be ejected by shrinking plastic. ejected from the sleeve.

    (2) The ejection force should be applied to the part with the strongest rigidity and strength of the plastic product (avoid acting on the thin section), and the movable surface should also be as large as possible, such as the protruding flange, the rib and the wall edge of the shell, etc. Most barrel products are released using the top plate.

    (3) In order to prevent the ejection marks from affecting the appearance of plastic products, the ejection position should be set on the hidden surface (inside) or non-appearance surface of plastic products; for transparent plastic products, special attention should be paid to the ejection position and ejection form. choose.

    (4) In order to avoid ejection marks and deformation of plastic products caused by vacuum adsorption, a combined ejection method or ventilation with porous steel can be adopted. For example, the ejector pin is combined with the top plate, or the ejector pin is combined with the ejector block. The thimble gap should be appropriately increased for ventilation, and an air intake valve should be used if necessary.

    (5) The ejector mechanism should be reliable and flexible, with sufficient strength and wear resistance. For example, for the ejector with swing rod and wedge, the strength and wear resistance of the sliding surface should be improved, and a lubricating groove should be designed on the sliding surface; nitriding treatment can be applied to improve the surface hardness and wear resistance.

    The selection principles of the selected thimble are as follows:

    (1) Choose a thimble with a larger diameter. That is, when the ejection area is large enough, larger diameter and larger thimble should be used.

    (2) The size of the thimble should be as small as possible. When using a thimble, the size of the thimble should be adjusted to minimize its size, and the preferred size series should be selected as far as possible.

    (3) The selected thimble should meet the requirements of ejection strength. When ejecting, the thimble should bear greater pressure. In order to avoid the deformation of the small thimble, when the diameter of the thimble is less than 2.5mm, the shoulder thimble should be used.

    (4) The diameter of the thimble is preferably an integer. Do not make it decimal or non-standard, such as Ø 3, 4, 5, 6, and 8.

    Taizhou Huangyan Jinhong Plastic Mould Parts Co., Ltd. is a manufacturer of injection plastic mold from China. The company is good at mold date inserts, specializing in the production and sales of positioning components, mold parts, and other injection molding products. The company can provide special products.