The ejector pin is the steel pin located on the B side of the die. When the ejector system is activated, the pins push the plastic part or runner system out of the mold. The ejector sleeve is a hollow cylinder surrounding a fixed center pin. When the ejection system is activated, the sleeve slides on the center pin. It pushes the plastic part off the center pin and out of the mold. Ejection sleeves often help to eject part features, such as hollow bosses.

ejector pin do not always have a circular cross-section over the entire length of the thimble. In many cases, the shape of the pin tip perfectly matches the mirrored contour groove (hollow boss) in the plastic part. Therefore, it is critical that the ejector does not rotate because it no longer fits correctly with the formed groove in the part. An anti-rotation system prevents the injector from spinning. You can choose from four different types of anti-rotation systems. Both types prevent rotation by machining the shoulder of the thimble. The other two are used in combination with stop pins to prevent the ejector from rotating.

The ejector must be long enough to eject the plastic part or runner from the mold. If the supplied ejector is longer than required, it can be trimmed to more closely match the plastic part or runner.

When the product has a hollow column structure and a large height, a thimble sleeve is required. Socket pins are usually fixed in the injection mold with headless screws. However, when several socket pins are very close to each other, briquettes and socket head cap screws will be used to secure them. The fixing hole of the button generally adopts the sleeve ejector, without exception, the standard ø3.57 x ø1.59 sleeve is used. When the standard-size sleeve cannot be used, the hole size must be kept unchanged, and the outer circle should be appropriately enlarged to make the application of the standard sleeve possible.

Taizhou Huangyan Jinhong Plastic Mould Parts Co., Ltd. is an injection mold maker from China, The company sells straight ejector pin and other related products.