1、 Layout principle of die ejector pin

(1) The ejector pin shall be arranged so that the jacking force is balanced as much as possible. The demoulding force required for the parts with complex structure is large, and the number of thimbles shall be increased accordingly.

(2) The thimble should be set at the effective part, such as bone position, column position, step, metal insert, local thick glue and other parts with complex structure. The thimbles on both sides of the bone position and column position should be arranged symmetrically as far as possible, and the distance between the thimble and the edge of the bone position and column position is generally D=1.5mm. In addition, try to ensure that the central line of the ejector pins on both sides of the column passes through the center of the column.

(3) Avoid setting the ejector pin across the steps or on the inclined plane. The top surface of the ejector pin should be as flat as possible, and the ejector pin should be placed on the structural part of the rubber part with good stress.

(4) Flat thimble shall be used in the deep bone position of rubber parts (depth ≥ 20mm) or when it is difficult to arrange the round thimble. When using the flat ejector pin, insert the flat ejector pin as much as possible to facilitate processing.

(5) Avoid sharp steel and thin steel, especially the top surface of the thimble shall not touch the front mold surface.

(6) The distance between the thimble and the waterway shall be considered for the layout of the thimble to avoid affecting the processing and water leakage of the waterway.

(7) Considering the exhaust function of the ejector pin, in order to exhaust during ejection, the ejector pin shall be arranged at the position easy to form vacuum.

(8) For rubber parts with appearance requirements, the thimble shall not be arranged on the appearance surface, and other ejection methods shall be used.

(9) For transparent rubber parts, the thimble shall not be arranged at the position requiring light transmission.

2、 Selection principle of die ejector pin

(1) Select the thimble with larger diameter. Namely, if there is enough ejection position, the thimble with larger diameter and preferred size shall be selected.

(2) The specification of thimble shall be as few as possible. When selecting the thimble, the size of the thimble shall be adjusted to minimize the size specifications, and the preferred size series shall be selected as far as possible.

(3) The selected ejector pin shall meet the requirements of ejection strength. When ejecting, the thimble shall bear large pressure. To avoid bending and deformation of the small thimble, when the diameter of the thimble is less than 2.5mm, the supporting thimble shall be selected.