The top of many institutions of different types, classification, can generally be classified in the following manner.
  1.according to the ejection motion classification mechanism. An ejection mechanism is the ejection mechanism is the most commonly used plastic parts, only by a single action can release; two ejection mechanism, plastic parts for the ejection mechanism of two different actions to release, the structure is more complex; delayed ejection mechanism in the top plastic parts after the top gating system the aggregate, used for submarine gate mould.
  2.according to the operation mode classification. Manual ejection mechanism in the plastic molding, by manual ejection mechanism of plastic parts removed; excited operating ejector mechanism in plastic molding, injection mold machine using actions to make plastic parts ejection; hydraulic ejector mechanism in the plastic molding, mold to a certain distance, the hydraulic ejector mechanism of action to achieve the release; pneumatically operated ejection mechanism by a special device, the compressed air, through the cavity in the processing of micro ejector air hole or valve, the plastic blow.
  3.The part classification according to the top of die structure. Push rod type ejection mechanism is arranged on the top rod is fixed on the board pushing plastic parts ejection; pipe jacking type liftout mechanism comprises a jacking the entire surrounding push plastic parts and mold release, especially plastic parts ejection in the circular, cylindrical, with center hole; push plate ejector mechanism is composed of a push plate an area of relatively large top out of plastic parts and mold, suitable for large cylindrical plastic parts, thin wall container, shell and the surface does not allow the top plastic parts traces; pushing type ejection mechanism is composed of a smaller block top out of plastic parts and mold, suitable for flange plastic molded parts; the ejecting mechanism for this is the use of movable parts in the top bar effect, is the plastic parts ejection; combined top two or more than two kinds of ejection parts joint push plastic parts with mechanism, releasing.