Early PCB boards were mostly soldered, but with the upgrading of electronic products, miniaturization of connectors, and requirements for high reliability and environmental protection, crimping has become the main connection method.
There are many types of connector connection methods, which can basically be divided into two categories: wiring (connecting with cables) and connection boards (connecting with PCBs). Crimp and Press-in are the most common connection methods in these two categories.
Press-in: Low cost and high efficiency
The definition of a press-in connector is that a pin (also called a terminal) is pressed into a hole smaller than its outer diameter by external force. This press-in connection is called Press-fit, also called crimping. Because it is lower in cost, higher in efficiency, simpler in operation, and more reliable than SMT (that is, surface mount technology, which is a splice technology), it is widely used in communications and computer industries.
The industry has designed various forms for Press-fit terminals, each of which has advantages and disadvantages. Among them, the fisheye hole terminal is the most widely used Press-fit terminal structure. A typical fisheye terminal is divided into 5 areas.
For complex crimping, crimping dies up and down are essential.
Press-fit connectors also have a special application for three-board intercommunication (as shown in the figure above). Compared with the welding technology that can only be used for two-dimensional panels, it has a wider range of uses. The disadvantage is that it requires high PCB Complex detection and so on.
Crimp Connection: high wiring quality
Crimp is a cold-pressing technology that dates back to around 1940. Its principle is to complete the crimping of metal wires and pins with the help of crimping tools or crimping tools. This crimp has good air tightness, corrosion resistance, and wire deformation must exceed its yield point, so it can achieve reliable data, signal, and power transmission. During the crimping process, the oxide layer or vulcanization layer of the wire can be removed to ensure a durable electrical connection with the residual elasticity of the pin and the wire.
This method is suitable for category 2, 5, and 6 wires with a diameter of 0.08mm² to 240mm². There is evidence that solid wires can also be crimped, but the quality of the crimp needs to be checked and confirmed. The following figure is an illustration of various types of cables, multi-stranded wires after crimping, and the internal structure of multi-stranded wires.
The crimp connection has the advantages of compact structure, reliable connection, reliable shock resistance, and on-site operation by special tools. Compared with ordinary screw connections, crimping provides the largest possible connection density, that is, the maximum number of connection channels can be provided per unit area. Because the connection principle is cold pressing, the connection has good air tightness and the connection quality is very high. Of the known wiring technologies, the quality of crimping is the highest.
In general, there is no absolute good or bad connection method for connectors, only suitable and unsuitable. When choosing a plug-in connector, you need to consider the structural requirements of the connector and the field use environment, and choose an appropriate connection method.
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