Research On The EMC Application Of Conductive Rubber On The Shielding Box

As the carrier of integrated electronic system, shielding box is widely used in many fields. The primary function of shielding box is to ensure the EMC performance of the electron equipment inside the box by minimizing or eliminating external electromagnetic interference, and the mark to evaluate the EMC performance is the Shielding Effectiveness of the box.Apertures or gaps are the main factors affecting the shielding effectiveness of the box. Besides of some functions of apertures including cooling etc, some gaps in fitting surface which resulted by mismachining tolerance or assembly error will lead to different levels of electromagnetic leakage. But, due to it's complex influence factors and difficult to determine parameters, it is difficult to study the electromagnetic leakage and electromagnetic shielding of those apertures or gaps, which is this paper focused on.Conductive rubber is the common and effective way to suppress the electromagnetic leaks between the covers of the box, so its application is getting more and more attention.Based on the electromagnetic compatibility of conductive rubber on the shielding box, Through browsing many reference and engineering handbooks of conductive rubber throughout the world, based on the theory of electromagnetic shielding and the mechanism of apertures leakage, by studying the physical performance of the conductive rubber,including the mechanic performance, electronic performance and the hermetic performance. Combined with the actual test and simulation about conductive rubber installed on the shielding box. Tested the electrochemical corrosion performance of four different conductive rubber and simulate the shielding effectiveness before and after the test. The paper has ultimately formed the theoretical basis for practical application about the conductive rubber installed on the shielding box.The primary research achievements are as following:1. The paper has discussed the all reasons of electromagnetic leaks of the box and given a generalization of physical performance about the conductive rubber when used on the shielding box. The paper also gives the methods to measure the EMC performance of the conductive rubber, and discusses the difference of different conductive rubber in EMC performance.2. Associated the indeed project, the paper has measured and simulated the shield effectiveness of the shielding box with conductive rubber, and analyzed the result of the measured data and simulated data.3. The paper has given the process of the designing of the mounting groove of the covers and the computing formula. The paper has also given the designed progress of the screw pitch and the computing formula when the conductive rubber needs required pressure.4. Four different kinds of conductive rubber with different filled grains and different metal finishing are tested with electrochemical corrosion under the standardized test. Through the compare of the data before and after the electrochemical corrosion test, a general conclusion to prevent electrochemical corrosion is reached of the four different kinds of conductive rubber and the metal.