Automatic testing method for concentricity quality of piezoelectric ceramic silver plate and device

Abstract

The invention discloses an automatic testing method for concentricity quality of a piezoelectric ceramic silver plate and a device. The method comprises the steps of acquiring a gray scale image by means of a camera, searching an external circle contour point set and an inner cycle contour point set of each piezoelectric ceramic silver plate in the image, performing circle curve fitting on the obtained point sets, calculating the circle centers and radiuses of the inner circle and external circle obtained through fitting, calculating concentricity of the inner circle and the external circle. The concentricity measured by each piezoelectric ceramic silver plate is compared with a preset concentricity threshold, and whether the piezoelectric ceramic silver plate is qualified or unqualified is determined one by one. After a system sets a quality threshold according to product type, adjustment of a random parameter is not required, and concentricity of the piezoelectric ceramic silver plates with different dimensions is measured automatically. The automatic testing method and the device have advantages of realizing high recognition accuracy, greatly improving automatic testing degree and improving production efficiency.

Description

Technical field [0001] The invention relates to the field of computer vision and quality detection research, in particular to a method and device for automatically detecting the concentricity of piezoelectric ceramic silver sheets. Background technique [0002] Piezoelectric ceramic silver sheet is formed by sintering piezoelectric ceramics, printing silver paste on the ceramic sheet by means of silk screen printing, and drying and sintering. The quality of the piezoelectric ceramic silver sheet is mainly determined by the following three aspects: (1) The concentricity of the ceramic sheet and the silver layer: the center of the circular silver layer printed in the circular piezoelectric ceramic sheet must be in line with the pressure. The outer circle of the electric ceramic sheet is concentric. When the deviation of the two centers is greater than a certain value, that is, when the concentricity is greater than a certain value, it is poor concentricity; (2) Poor sintering: the ...

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Problems solved by technology

This method has certain requirements for the minimum distance between the inner circle and the outer circle. If the distance between the inner circle and the outer circle is too close, the algorithm is prone to the phenomenon that the inner circle and the outer circle overlap together.

Since the inner circle formed by the silver paste printed on the piezoelectric ceramic sheet is generally very close to the outer circle of the ceramic sheet, it is easy to occur that the inner circle or the outer circle cannot be detected, so that the inner and outer circles cannot be calculated correctly. The concentricity of the circle; in addition, when the size of the circle changes, this method needs to adjust many parameters. If the parameters are not set properly, it is easy to fail to find the circle, resulting in the inability to calculate the concentricity

As a widely used series of products, piezoelectric ceramic silver sheets have many different sizes. The above method will make it difficult for workers to correctly adjust the parameters in the system, resulting in the system not working properly.

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