The terminal is a kind of accessory product which is used to realize electrical connection, which is divided into the category of connectors. With the increasing degree of industrial automation and more stringent and accurate industrial control requirements, the use of terminals gradually increases. With the development of the electronic industry, the use of terminal terminals is increasing and the variety is more and more. At present, the most widely used are not only the PCB terminal, but also hardware terminal, nut terminal, spring terminal and so on.
Terminal is applied for the convenience of the connection wire, it is actually a seal inside the insulation plastic pieces of metal, with a hole at both ends can be inserted into conductor, a screw is used to tighten or loosen, such as two wire, sometimes need to connection, sometimes need to disconnect, then connect them can use the terminal, and can be disconnected at any time, without having to weld them up or intertwined, very convenient. And suitable for a large number of wires connected, in the electric power industry is a special terminal, terminal box, above all terminal, single, double, current, voltage, ordinary, can be broken, and so on. A certain pressure area is to ensure reliable contact and to ensure sufficient current.
Terminals can be divided into, european-style terminal series, plug terminal series, transformer terminal blocks, wiring terminal buildings, fences terminal series, spring loaded terminal series, the series of rail type terminal blocks, wear wall type terminal series, photoelectric coupling type terminal 110 series, 110 terminals, terminal, terminal 250, 250 terminal, OD2.2 ring terminal, 2.5 ring terminal, 3.2 ring terminal, 4.2 ring terminal, 2 ring terminal, 6.4 ring terminal, 8.4 ring terminal, 11 ring terminal, 13 ring terminal type terminal and sheath series, all kinds of ring terminals, tubular terminals, terminal blocks, copper iron (2-03, 03, 04, 4-4-6-03, 04), etc.
Interpolation: it is connected by two parts, which are pressed together and then inserted into the other part. This part is welded to the PCB board. This vibration design ensures the reliability of the product's long-term airtight connections and finished products. Can add assembly ears on both ends of the socket, assembling the ear to a large extent can protect splicing and can prevent the splicing arrangement position, at the same time, this design can ensure outlet socket right into the matrix. The socket may also have assembly and locking positions. The assembly button can be more firmly fixed onto the PCB board, and the locking position can lock the mother and socket after the installation is completed. Various socket designs can be matched with different matrix insertion methods, such as horizontal, vertical or tilt to printed circuit boards, which can be selected in different ways depending on the customer's requirements. It is possible to choose the metric line gauge and the most popular terminal type on the market.
Palisade type: can achieve safe, reliable, effective connection, especially in large current, high voltage use environment is widely used.
Spring loaded: spring is used to a new type of terminal blocks, has been widely used in electrical and electronic engineering industry: lighting, elevator elevator control, instrumentation, power supply, such as chemical and auto power.
The plastic insulation materials and conductive parts of the terminals are directly related to the quality of the terminals, which respectively determine the insulation and conductivity of the terminals. Failure of any terminal will result in failure of the entire system project. The painful lessons at home and abroad are profound.
Prevention is the goal, analysis is the basis. In a sense, preventing failure is more important than analyzing failure. It has more realistic meaning to guarantee the quality and reliability of terminal.
From the point of use of the terminal, the function that should be achieved is: the contact area should guide the area, the contact is reliable. The place where the insulation should not guide must be insulated and reliable. There are three common fatal faults in terminal terminals:
1. Poor contact
The metal conductor inside the terminal is the core part of the terminal and it will be transferred from the external wires or the voltage of the cable, the current or the signal to the corresponding contact of the corresponding connector. The contact parts must have good structure, stable and reliable contact and good electrical conductivity. Due to the unreasonable contact element structure design, material selection error, the mold is not stable, processing out-of-tolerance size, surface roughness, plating surface treatment such as heat treatment process is unreasonable, improper assembly, storage conditions and improper operation, will be in contact with a contact part of the cause poor contact and cooperate with the parts.
2. Poor insulation
The effect of the insulator is to keep the contact parts in the correct position and to insulate the contact parts from the contact parts. The insulation must have excellent electrical properties, mechanical properties and process forming properties. Especially with the high density, the miniaturization terminal is widely used, the effective wall thickness of the insulator is thinner and thinner. This paper puts forward more stringent requirements for insulation materials, precision of injection mold and molding process. Due to the insulator surface or within the metal tailings, surface dust, flux, such as pollution of be affected with damp be affected with damp, organic material deposition and harmful gas adsorption film with surface water membrane fusion to form ionic conductive channel, absorption of moisture, mold, insulation aging, can cause short circuit, leakage, breakdown, low insulation resistance insulation fault phenomenon.
3. Fixed bad
The insulator not only insulates, but also provides accurate neutralization protection for the protruding contact parts, and also has the function of mounting positioning and locking on the device. Fixed bad, light person influence contact reliable cause instantaneous power off, serious is product disintegrate. Refers to the disintegration of terminals in close state, due to the material, design, technology and so on reasons for structure between plug and socket caused by unreliable, abnormal separation between pin and socket, will cause control system and signal control in power transmission interrupted serious consequences. Because the design is unreliable, the selection error, the forming process chooses the improper, the heat treatment, the mold, the assembly, the welding process quality poor, the assembly is not in place can cause the fixed bad.