RU1770885C - Eddy-current transducer - Google Patents

Abstract

The invention relates to non-destructive testing of materials and can be used to control printed circuit boards. The purpose of the invention is to improve the accuracy of quality control of electrical wiring on the surface of the contact pads of printed circuit boards by winding the eddy current transducer from two sections in series according to the included sections. These sections are located on a T-shaped plate, one of them at the end of the rack of the plate, the other at the end of the crossbar branch and rotated at an angle of 30 [deg.] the plane of turns towards the first section.

Description

The invention relates to the field of non-destructive testing of products and can be used to assess the quality of electrical connections in instrumentation, in particular electrical connections of wires and leads to contact pads of printed substrates.

An overhead eddy current transducer is known, consisting of coaxially arranged coils and a modulator made in the form of a rotating plate. Said eddy current transducer is intended for quality control of spot welded joints, typically sheet materials. However, when controlling the quality of electrical wiring connections having a complex geometry: wires or terminals of radio components with pads of printed circuit boards, such a converter has low accuracy due to the non-optimal configuration of the magnetic field.

Closer in technical essence to the claimed technical solution eddy current transducer containing

a T-shaped flat plate made of a dielectric or weakly magnetic material and a winding made of microwire located on it, each turn of which is made in the form of L-shaped loops, alternately covering the branches of the plate crossbar. The converter of this design also has a low sensitivity.

The aim of the invention is to improve the accuracy of quality control of electrical wiring on the surface of the pads of printed circuit boards by the eddy current method.

This goal is achieved by the fact that in an eddy current transducer containing a T-shaped plate of dielectric or weakly magnetic material and a winding located on it, according to the invention, the winding is made of two sections connected in series according to one, one of which is located coaxially with it , and the friend at the end of one of the branches of the crossbar and razso

with

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vermouth with the plane of its turns at an angle of 30 ° towards the first section,

The essential distinguishing features of the claimed technical solution include: the winding of the converter in the form of two sections in series according to the included sections; the arrangement of the sections on the plate so that the magnetic field of the winding closes through a controlled mounting connection; a 30 ° turn of the plane of the turns of the section located at the end of one of the branches of the crossbar.

In the table. Figure 1 shows experimental data illustrating the efficiency of rotation of a section of a winding in a CZO when controlling the quality of soldered wire connections.

These significant differences of the claimed technical solution make it possible to realize a positive effect, which consists in providing the ability to control the quality of mounting electrical connections by the eddy current method with high accuracy and reliability.

In FIG. 1 schematically shows the eddy current transducer of the claimed design; in FIG. 2 - eddy current transducer in conjunction with the control object.

The eddy current transducer of the claimed design (Fig. 1) contains a T-shaped plate 1 and a winding from a microwire in the form of sections 2 and 3. Section 2 is located at the end of the plate rack coaxially, and section 3 is located at the end of one of the branches of the crossbar and deployed at an angle of 30 ° towards the first section. Sections are wound according to and connected in series.

The converter operates as follows.

The plate with the winding is superimposed on the test object 5 (Fig. 2) so that the converter winding section 2 lies in the plane of the contact pad 4 of the printed circuit board, and section 3 in the plane enveloping the object to be checked 5 (in this case, it is an insulated microwire,

connected to the pad 4 by microwelding). When the measuring current passes through the transformer winding, section 2 excites eddy currents in the contact area 4, and section 3 excites eddy currents in the controlled object 5.

Since the sections are connected in series, the eddy currents of the sections are closed through a controlled electrical

a connection whose quality condition is fixed by the electromagnetic mode of the converter.

In the table. 2 shows experimental data illustrating the increase

accuracy and reliability of quality control for an existing eddy current transducer in comparison with the prototype.

Thus, the distinguishing features of the claimed technical solution allow realizing a new positive effect, which consists in increasing the accuracy of the control by 2-4 times.

Claims (1)

The claims Eddy current transducer comprising a T-shaped plate of dielectric or weakly magnetic material and a winding located on it, characterized in that, in order to increase precision control of the quality of electrical wiring on the surface of the contact pads of printed circuit boards, the winding is made of two successively connected sections, one of which is located at the end of the plate rack coaxially with it, and the other at the end of one of the branches of the crossbar and is rotated by the plane of its turns at an angle of 30 ° towards the first section. T a 6 l and 1 Table 2 % r.l