I. die thimble arrangement principle
(1) thimble layout should make the top force as balanced as possible. The number of thimbles should be increased as the demodulation force is larger in complex parts.
(2) the thimble should be set in the effective place, such as bone position, column position, step, metal insert, local thick glue and other complicated parts. The ejectors on both sides of bone and column positions should be arranged symmetrically as far as possible. The edge spacing between ejectors and bone and column positions should be D=1.5mm. In addition, the center line of the thimble on both sides of the column should be ensured to pass through the center of the column.
(3) avoid crossing steps or setting a thimble on the inclined plane. The top surface of the thimble should be as flat as possible.
(4) flat thimble should be used at the deep bone position (depth ≥20mm) of the adhesive part or when it is difficult to arrange a round thimble. When using flat thimble, the flat thimble should be in the form of insert to facilitate processing.
(5) avoid sharp steel, thin steel, especially the top surface of the thimble from touching the front die surface.
(6) the edge spacing between the thimble and the channel shall be considered to avoid affecting the processing and leakage of the channel.
(7) consider the exhaust function of thimble. In order to exhaust during ejecting, the thimble should be arranged in the parts where vacuum extraction is easy to be formed.
(8) for rubber parts with appearance requirements, the thimble cannot be arranged on the appearance surface, and other ejecting methods shall be adopted.
(9) for transparent adhesive parts, thimble shall not be arranged in the part requiring light transmission.
Second, the mold thimble selection principle
(1) choose a thimble with a larger diameter. In the case of sufficient ejecting position, the thimble with larger diameter and priority size should be selected.
(2) select thimble specifications should be as little as possible. When selecting a thimble, the size of the thimble should be adjusted to minimize the size specification, and the preferred size series should be selected as far as possible.
(3) the selected thimble shall meet the ejection strength requirements. When ejecting, the thimble shall bear greater pressure. To avoid bending deformation of the small thimble, a supporting thimble shall be selected when the diameter of the thimble is less than 2.5mm.