Graphite die for shell package:
1. The seal is mainly composed of base, central pin and glass insulator. The central pin of the traditional metal glass seal is in the shape of a straight rod, and the structure is relatively simple
2. The package requires both ends of the pin to be flattened. This product requires that both ends of the pin be flattened in the same vertical direction, and the pin is located in the center of the glass insulator.
3. For the typical structure of the above metal and glass sealing parts, when the pin is not centered or straight in the glass, there will be uneven sealing stress, which will affect the risk of glass cracking.
4. Therefore, the limit of pins and the straightness of glass should be considered in the design of graphite mold. When designing the die, it is necessary to obviously restrict the degree of freedom of the pin in order to effectively ensure the straightness of the pin.
5. Therefore, when selecting the positioning lower die and positioning upper die, the straightness of the upper and lower dies shall be ensured. The initial die structure adopts the method of annular groove for both upper and lower dies,
6. The pin can slide freely in the annular groove, which will cause the pin to skew in the molten glass at high temperature. Many enterprises have changed the positioning lower die structure to the drilling method,
7. It restricts the degree of freedom of the pin and the upper die, but the positioning of the upper die is still the ring groove method. Although it reduces the skew probability of the pin, it often happens that it is not straight to the center of the glass.
8. The upper and lower dies of the designed graphite die cooperate to select the limit of square groove, which avoids the rolling in the circular groove of the upper die and the lower die, which is not controlled by the degree of freedom. On other molds
9. Flattened fixing grooves are designed in the lower die structure to ensure that the flattening direction is the same up and down and straight to the center of the seal glass.
