How to soldering screw type feedthrough capacitor/filter

The core of screw type feedthrough capacitors or screw type feedthrough filters is a disc-shaped multilayer or tubular ceramic capacitor. It has the same properties as other ceramic articles and will be damaged by mechanical vibration, sudden temperature changes and excessive voltage. For the installation of feedthrough capacitors or filters on the circuit board, care must be taken to minimize various stresses when soldering the guide pins of the filter and shaping. Here are some related considerations:

Install direct soldering feedthrough capacitor (filter)

*The soldering   process should be controlled so that the filter will not be subjected to sudden thermal shock and cause the internal ceramic capacitor to break.

*The speed is kept at 2°C/sec when warming up. In fact, depending on the different substrates and components, there are examples of successful welding in the range of 1.5~4℃/sec.

*It is necessary to use soaking zone before soldering. This makes the substrate temperature uniform without deformation. Upon cooling, any substrate deformation recovery will generate stress that damages the filter.

*The soldering material can be Sn60, Sn62 (Non-ROHS), Sn-0.7Cu, Sn-Ag (ROHS) or similar types.

*Soldering time should be as minimal as possible, and the temperature should be controlled to no more than 400 ℃ (suitable for welding through core series). Natural cooling should be used for cooling to room temperature. Let the temperature difference stress of the welding point gradually relax, avoiding the airflow cooling. Forced airflow cooling will cause temperature difference damage, and it is easy to damage the ceramic capacitor by cleaning with cold liquid immediately after welding.

　　Terminal Soldering

Whether it is a screw type or a direct soldering type, the following points should be noted when soldering the guide pin:

* The temperature of the soldering iron end should not exceed 400°C, and the soldering material can last up to 3 to 5 seconds to minimize the risk of thermal shock to damage the capacitor.

*The soldering material can be Sn60, Sn62 (Non-ROHS), Sn-0.7Cu, Sn-Ag (ROHS) or similar types.

* Use a radiator between the welding point and the shell as much as possible, especially when the welding time is long.

　　Install Screw Type feedthrough capacitor (Feed-through filter)

Installation rotation force: When installing the filter to the partition or panel, the installation rotation force recommended relative to the housing should be used. This is an important point. Otherwise, the internal capacitor may be damaged due to deformation of the housing. When installing to a threaded hole, the maximum installation torque should be 50% of the recommended nut.

Installation tool: The hexagonal new Chenyang electronic filter should be installed with a suitable sleeve. The following method is used for round (can not be installed with pliers tool, so as not to damage the filter). A circular filter with a slot at the top can be screwed into the threaded hole with a simple special tool.

Grounding: In order to ensure the normal operation of the filter, the shell of the filter must be sufficiently connected to the ground of the panel to provide an effective path for interference. Adhesive locking is not recommended. If it is to be used, it should be used after the filter is installed.

Minimum board thickness: The user should note that sometimes the feed-through filter has an undercut between the thread and the mounting edge of the housing. When the thickness installed in the board is less than the length of the relief groove, the tight fit of the threaded hole and the positioning of the filter will cause problems. Therefore, where possible, the thickness of the panel should be greater than the length of this relief groove.

Maximum plate thickness: This indicator is used to ensure that the nut can be completely toothed if the gasket is used.

　　Curved trim of the guide pin

The bending of the feedthrough capacitor or the guide pin of the filter should not be carried out within 4 mm of the epoxy seal, and the guide pin should be supported when trimming the guide pin.