Considering the exhaust function of the spring thimble
1. The spring thimble should be set to make the ejection force as balanced as possible. The complex structure requires a large demolding force, and the number of casing pipes should be increased accordingly.
Second, the spring thimble should be placed on the effective parts, such as bones, columns, steps, metal inserts, local thick glue and other parts with complex structures. The top needles on both sides of the bone position and the column position should be arranged as symmetrically as possible. The distance between the spring thimble and the bone position and the position of the column position is generally D = 1.5mm. Make sure that the center lines of the thimble on both sides of the column position pass through the center of the column position.
3. Prevent steps or spring thimble on inclined surfaces. The top surface of the thimble should be as smooth as possible. The thimble should be placed on the structural part with good force.
4. When the rubber part has a deep bone position (depth ≥20mm) or it is difficult to set a dome needle, use a flat thimble. When a flat thimble is needed, the flat thimble should be selected as an insert to facilitate processing.
5. Prevent sharp-point steel, thin steel, especially the top surface of the thimble, from contacting the front mold surface.
6. The arrangement of spring thimble should consider the edge distance between the thimble and the water delivery channel to prevent affecting the processing and water leakage of the water delivery channel.
Seven. Considering the exhaust function of the ejector pin, in order to eject the ejector, the spring ejector pin should be placed in the part that is easy to form a vacuum. For example, in the large plane of the cavity, although the rubber component has a small packaging force, it is very easy to form a vacuum, which will cause an increase in the release force.
8. For plastic parts with appearance requirements, spring thimble cannot be placed on the design surface, and other spraying methods must be used.
Nine. For transparent plastic parts, the thimble cannot be placed in the part that needs light transmission.
10. Choose a thimble with a relatively large diameter. That is, under the condition of sufficient spraying position, a thimble with a larger diameter and preferred size should be used.