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Electromagnetic detecting method for detecting defects in thin metal foil

An electromagnetic detection and metal foil technology, applied in the direction of material magnetic variables, etc., can solve the problems of slow speed, inability to realize real-time online monitoring, low efficiency, etc., and achieve the effect of high measurement efficiency, real-time detection and feedback, and high measurement accuracy.

Inactive Publication Date: 2019-05-10
UNIVERSITY OF CHINESE ACADEMY OF SCIENCES
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At the same time, this method also has disadvantages such as low efficiency, slow speed, and inability to realize real-time online monitoring.

Method used

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  • Electromagnetic detecting method for detecting defects in thin metal foil
  • Electromagnetic detecting method for detecting defects in thin metal foil
  • Electromagnetic detecting method for detecting defects in thin metal foil

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Embodiment Construction

[0019] The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0020] Basic principle of the present invention is as follows: as figure 1 As shown, a local static magnetic field B is provided by a small-sized permanent magnet, and an electromagnetic sensitive area is established in the metal foil. The range is about three times the size of the small magnet, and all changes in electromagnetic parameters are mainly concentrated in this sensitive area. Make relative movement between the small permanent magnet and the metal foil sample to be tested, and according to Ohm's law, a pair of eddy current rings J with opposite current directions are generated in the metal foil. According to Ampere's law, the eddy current induces a secondary magnetic field b around it.

[0021] When heterogeneous defects such as pinholes enter the electromagnetic sensitive area with the movement of the meta...

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Abstract

The invention relates to an electromagnetic detecting method for detecting defects in a thin metal foil, wherein the method comprises the following steps: step 1, placing a small-sized permanent magnet in the vicinity of the metal foil to be tested and generating relative motion, so that eddy current is induced in the metal foil; step 2, measuring a change of an induced secondary magnetic field around the metal foil to be tested caused by the occurrence of heterogeneous defects such as a pinhole in the metal foil via a magnetic field sensor; and step 3, determining the characteristics and location of the defect through the change of the induced secondary magnetic field. According to the electromagnetic detecting method provided by the invention, the defects in the metal foil are detected based on the principle of electromagnetic induction, so that the measurement principle is clear; the measuring instrument has a simple structure; the measuring accuracy is high; the measuring efficiency is high; and real-time online detection and feedback are achieved, the production is not interfered, and the electromagnetic detecting method can adapt to different occasions.

Description

technical field [0001] The invention relates to an electromagnetic detection method for defect detection in thin metal foil, in particular to the detection of defects such as pinholes and scratches in aluminum foil. Background technique [0002] Metal foil is a very thin metal sheet, the thickness is generally less than 200μm, and it is mostly manufactured by hammer forging or rolling. Metal foil materials are mostly made of materials with good ductility, such as gold, aluminum, copper, nickel, tungsten, tin and other rare earth metals. Metal foils of different materials have different uses. Gold, silver, nickel and copper foils can be used for decoration or packaging; copper-nickel or nickel-chromium resistance alloy foils are used to make force-measuring stress gauges, precision resistors, and audio and video equipment; tungsten foils can be used for special electronic tubes ;Tin foil is mainly used in the fields of medicine, chemical industry, light industry, food, art s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/90
Inventor 施博王勃王晓东
Owner UNIVERSITY OF CHINESE ACADEMY OF SCIENCES
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