Coordinate algorithm of MARK points on printed board in high-precision printing machine based on machine vision

Abstract

The invention discloses a coordinate algorithm of MARK points on a printed board in a high-precision printing machine based on machine vision, which can reasonably, reliably and accurately realize thepositioning of MARK. The algorithm is reasonable and the technical scheme is efficient and reliable. The coordinate algorithm comprises the following steps: (1) primarily aligning a printed steel screen and the PCB, and moving each group of MARK points to align to partially coincide; (2) driving a camera by a two-dimensional driving mechanism and then moving the camera to the mechanical origin; (3) the coordinates of the mechanical origin measured by the camera being (H, L); (5) measuring a Mark point A on the PCB in the camera field of view to obtain the initial pixel coordinate (xp1, yp1) of the mark point and the mechanical coordinates (xj1, yj1) at this time, calculating to obtain the actual coordinates of the MARK point A being X=x1+D<xj1>-DH; X=y<p1>+D<yj1>-DL, in the sameprocess, measuring the actual coordinates of a MARK point B on the PCB in turn, and measuring the actual coordinates of MARK points C and D on the printed steel screen in turn; and (6) performing driving by the two-dimensional driving mechanism.

Description

technical field [0001] The invention relates to an alignment algorithm on a printing machine, which is specifically used for positioning the MARK points of a PCB board and a printing steel net in a solder paste printing machine. Background technique [0002] In the SMT industry, circuit boards are coated with solder paste by a printing machine, and then undergo component assembly and reflow soldering processes, and finally realize the complete production of PCBs; the printing machine in the prior art has been converted from manual coating to semi-automatic printing. , the cylinder drives the scraper and the stencil to drop to the surface of the PCB. After the scraper lands, the solder paste is repeatedly scraped left and right along the surface of the stencil; the reason why this process is semi-automatic is that it is necessary to manually fix the PCB on the fixture and remove it manually. process, which is a waste of time; [0003] We are committed to making a fully autom...

AI Technical Summary

Problems solved by technology

[0002] In the SMT industry, circuit boards are coated with solder paste by a printing machine, and then undergo component assembly and reflow soldering processes, and finally realize the complete production of PCBs; the printing machine in the prior art has been converted from manual coating to semi-automatic printing. , the cylinder drives the scraper and the stencil to drop to the surface of the PCB. After the scraper lands, the solder paste is repeatedly scraped left and right along the surface of the stencil; the reason why this process is semi-automatic is that it is necessary to manually fix the PCB on the fixture and remove it manually. process, which is a waste of time;

[0003] We are committed to making a fully automatic solder paste printing machine, and at the same time we need to improve the squeegee coating accuracy; in the design of a fully automatic printing machine, the alignment between the printing screen and the PCB is very important, and the current alignment is only through MARK Points for laser through test alignment, or manual alignment; due to insufficient light and lighting environment, these alignment methods have some disadvantages, cannot be reliable and accurate alignment; it is also not conducive to the realization of a fully automatic alignment process

In order to achieve fully automatic alignment, we have designed a visual alignment component, which is set up with an industrial camera as the core, and can automatically align, but the alignment process needs to be moved to adjust the interaction between the industrial camera and the MARK point, as well as the mesh board and the PCB board. Positional relationship; the existing technology does not have a MARK point positioning algorithm suitable for our automatic solder paste printing machine, and the current positioning technology based on laser technology and grating ruler positioning has low accuracy in the positioning process

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