When using connectors, we often encounter some failure situations. How can we further make accurate judgments? This article will analyze the improvement methods of two common causes of connector failure.
1, The inner conductor is not firmly fixed
For assembly purposes, in the structure of many RF coaxial connectors (such as N-type, 3.5mm), the inner conductor is divided into two sections at the dielectric support and then connected together with threads. However, due to the small diameter of the inner conductor, if glue is not applied to fix the threaded connection during assembly, the strength of the inner conductor connection will be very poor, especially for some small RF coaxial connectors. Therefore, when the connector is repeatedly connected and disconnected, under the long-term action of torque and tension, the internal conductor threads may loosen and fall off, leading to connection failure.
One of the commonly used structures for RF coaxial connectors is the inner conductor, dielectric support, and outer conductor fixed together with adhesive. If the amount of glue applied or the connection strength of the glue is not sufficient during assembly, the glue coated area may break due to stress during use, causing the inner conductor to rotate or move axially, resulting in poor electrical contact between the inner conductors and connection failure.
Improvement method: When assembling coaxial connectors, an appropriate amount of conductive adhesive or thread locking agent can be applied to the threaded connection to increase the reliability of the threaded connection. Choose adhesives with high bonding strength, and ensure that the adhesive fills the entire coating hole when applying; Roll the adhesive on the inner conductor to increase the contact area between the inner conductor and the adhesive, preventing the inner conductor from rotating; Adjust the radial dimensions and tolerances of the inner conductor, outer conductor, and dielectric support appropriately to achieve an interference fit between the inner conductor and dielectric support, as well as between the dielectric support and outer conductor. This can also make the assembly of the three more secure.
2, The size of the socket or pin for the inner conductor is incorrect
If the diameter of the conductor inside the socket is smaller than the specified size, when the conductor inside the pin enters the socket, it will cause the socket to expand excessively, the deformation amount will exceed its elastic deformation range, and plastic deformation will occur, resulting in damage to the conductor inside the socket; On the contrary, if the diameter of the pin is too small, when the pin is matched with the socket, the gap between the pin and the socket wall is too large, and the two inner conductors of the connector cannot be in close contact, resulting in increased contact resistance and poor electrical performance indicators of the connector.
Improvement method: Whether the fit between the socket and the pin is reasonable can be measured by the insertion force and retention force of the standard gauge pin and the conductor inside the socket. For N-type connectors, the insertion force when the diameter of the standard gauge pin is matched with the socket should be ≤ 9N, while the retention force when the diameter of the standard gauge pin is matched with the conductor inside the socket should be ≥ 0.56N.
