Dongguan Lowei Electronics Technology Co.,Ltd
东莞市逻维电子科技有限公司
​What is shielding wire?
 

What is shielding wire?
Shielding wire wrap signal lines up is to use mesh woven wire transmission line.
Outer conductor wire is shielded wire conductor package, parcel conductor is called shield, generally for knitting brass or copper (aluminum piece, etc.), need to ground the shield to avoid jamming signal into the inner conductor dry all at the same time reduce the wastage of the transmitted signal.With common woven wire, coil wire belong to shielded wire.
 
Ordinary shielding wire production process is as follows:
 
Copper - (filling) - winding (core) - package aluminum piece - woven out of (or winding) - (be) - cutting line - decortication - shell core - welding - - injection molding - appearance check - in the finished product testing, winding, packing.A total of 16 sets of processes.
 
Electronic cables:
 
AL on behalf of the aluminum piece.Such as: 4 c + AL, which means four core wire package aluminum piece.
 
AB on behalf of the weaving Such as: 4 c + 80/0.10 AB, mean 4 core braided wire, weaving the specifications for the 80 0.10 mm outside diameter of copper wire.
 
S on behalf of the winding Such as: 4 c + 60/0.10 S, mean 4 c winding wire, coil of the specifications of the 0.10 mm outside diameter of copper wire is 60.(the difference between the winding and weaving see our feature article)
 
Second, the shielding effect
 
Shielding is between two space area for the isolation of the metal, to control the electric field, magnetic field and electromagnetic waves from one area to another area of induction and radiation.Specifically, is to use the shield components, circuit, assembly, cable, or the interference sources of the whole system surrounded by preventing interference of electromagnetic field to spread beyond;With a shield to enclose the receiving circuit, equipment or system, prevent them from affected by external electromagnetic fields.For shield from wires, cables, components and circuits or systems such as external electromagnetic interference and electromagnetic waves are internal plays an energy absorption (eddy current loss), reflection energy (electromagnetic wave in the interface reflection on the shield) and offset energy (electromagnetic induction in the inverse electromagnetic shielding layer, can offset part of the interference of electromagnetic wave), so the shield has weakened the function of the interference.(1) when the frequency of electromagnetic field interference, using eddy current generated in low resistivity of metal materials, formation of external electromagnetic wave offset function, so as to achieve the effect of shielding.(2) when the frequency of the interference of electromagnetic wave is low, to adopt high permeability material, so that the lines of magnetic force limit inside the shield, to prevent the spread to the shielding room.(3) in some cases, if the requirement of high frequency and low frequency electromagnetic fields have good shielding effect, often with different metal materials composed of multilayer shield.Many people don't understand the principle of electromagnetic shielding, think that as long as the use of metal in a box, then put the box grounding, can have the effect of electromagnetic shielding.In this concept under the guidance of the result is failure.Because, electromagnetic shielding and shielding grounding or not it doesn't matter.Really only affect shield shielding efficiency of the two factors: one is the entire surface of the shield must be conductive row, the other one is not directly penetrate the shield conductor.Shield, there are a lot of conductive discontinuous points on the shield is the main type of different parts of non-conductive gap junction.The electromagnetic leakage, non-conductive gap is produced as fluids will leak from the crack on the container.A way to solve this kind of leakage is filled conductive elastic material in aperture place, remove the conductive point.It's like in gaps fluid container filled rubber.The elastic conductive filler material is electromagnetic sealing gasket.In many literatures, electromagnetic shield as liquid sealed container, seems to be only when the conductive elastomeric seal gap so far to prevent electromagnetic leakage.In fact, this is not exact.Because cracks or holes will leak electromagnetic waves, depends on the gap or hole relative to the size of the electromagnetic wave.When the wave in the long run is greater than the opening size, does not have obvious leaks.Therefore, when the interference of high frequency, short wavelength at this moment, you need to use electromagnetic sealing gasket.Specifically, when the disturbance frequency of more than 10 MHZ, consider using electromagnetic sealing gasket.All good elastic and conductive materials can be used for electromagnetic sealing gasket.Electromagnetic sealing gasket is made according to this principle, conductive rubber, silicone rubber in filling the total weight of 70 ~ 80% proportion of metal particles, such as silver, copper powder, aluminum powder, copper powder, aluminum powder, silver plated silver plated silver glass ball, etc.Keep part of the silicone rubber elasticity good features of this material, at the same time has good electrical conductivity.Metal mesh grid: use beryllium copper wire, monel wire or stainless steel wire woven tubular strip, shaped like a shielded cable shielding layer.But it's different weaving method and the cable shielding layer, cable shielding layer is woven with many wires, and this kind of screen liner is made by a thread.Make an image of the metaphor, like sweater sleeve.In order to enhance the flexibility of metal mesh, sometimes in net tube join rubber core.Finger reed: beryllium copper into the reeds, has the very good elasticity and electrical conductivity.Electrical conductivity and flexibility.Multiple conductive rubber: consists of two layers of rubber, the inner layer is ordinary silicon rubber, the outer layer is a conductive rubber.This material has overcome the disadvantages of traditional conductive rubber elasticity bad, to fully embody the rubber elasticity.Its principle, some like with rubber core wire mesh.Choose to use what kind should consider four factors: when electromagnetic sealing gasket shielding effectiveness demands, environmental sealing requirements, installation structure and cost requirements.The characteristics of the different packing material, shielding according to the mechanism can be divided into electric field shield, magnetic screen and electromagnetic shielding.