Overview of ceramic pins

Ceramic pins, also known as fiber optic ceramic inserts. A finely aligned cylinder in a ceramic pin plug, with a microhole in the center, used to fix an optical fiber. It is a kind of high precision special ceramic element made of nano-zirconia (ZrO2) material through a series of formulations, processing, its aperture and roundness error is 0.5 degrees. The connector is a detachable and classified optical fiber movable connector, which makes the connection and conversion scheduling of optical channel more flexible and can be used for debugging and maintenance of optical communication system.

Ceramic pin case is widely used in high reliability package of power electronic devices, such as typical to254, to256 series package. The sealed shell guide pin generally has two sealing forms, one is the end seal, the other is the shaft seal. Both of these sealing forms have certain air tightness problems in the production process.

For the end sealing structure, the surface bonding is formed by metallization welding between the welding ring and the porcelain surface. At the same time, the gap between the lead pin and the welding ring is filled with silver copper solder to form the sealing structure of the welding ring, porcelain and the lead pin. In this structure, due to the different coefficient of thermal expansion between ceramic parts, welding ring and guide pin, during the heating and cooling process of high temperature welding, the metallized edges of welding ring and ceramic parts are subjected to greater stress, which is easy to be pulled apart by solder, leading to the problem of air tightness.

The shaft seal structure is filled with silver copper solder in the metallization of the porcelain hole and the guide pin, which directly forms an airtight seal. This sealing form requires high clearance accuracy between the hole and the guide pin. If the clearance is too narrow, the guide pin can not be inserted smoothly, assembly and welding can not be done; If the gap is too wide, the solder can not fill, resulting in welding holes. The small fluctuation of the gap size will also lead to the solder quantity can not be accurately controlled, resulting in air tightness problems.

Because electronic force electronic devices are widely used in military industry, rail transit, automobile and other power conversion fields, the demand is great. Therefore, improving the airtight reliability of this kind of package housing has good application prospect and social benefits.