Component Mounter Deviation Correction for BGA Placement
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Solution Overview
Problem
Existing electronic component mounters face inaccuracies in mounting components on circuit boards due to misalignment caused by the positional relationship between components and the light source, leading to deviations in recognized positions, especially with BGA-type components and curved sections, which affects mounting precision.
Innovation Solution
The component mounter is equipped with a camera, image processing, and a recognized position deviation correction mechanism that measures and corrects the positional deviations caused by the light source, using memorized data to align components accurately within the camera's field of view, ensuring precise mounting even when multiple components are imaged simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple components are gathered within the same camera field of view and imaged simultaneously to reduce the number of times images are taken, then productivity is improved, but the recognized position of components deviates due to misalignment with the light source center causing light and dark condition changes
Solution Approach 1:
The system performs preliminary measurement of recognized position deviation for each component type before actual production. The measured deviation values are stored in a lookup table, allowing the image processing means to directly retrieve and correct deviation values during production without performing complex calculations in real-time, thus enabling both high productivity and high precision
Solution Approach 2:
The patent replaces complex real-time optical calculation and measurement systems with a simplified lookup table approach. Instead of calculating light source effects during production, the system substitutes this with pre-measured deviation data retrieval based on component position and type, significantly simplifying the image processing while maintaining accuracy
2Illumination intensity
If the center of the camera field of view and the center of the light source are aligned, then the illumination is optimized, but components positioned away from the center still experience changing light and dark conditions based on their distance from the light source center
Solution Approach 1:
The patent applies local quality by measuring and correcting recognized position deviation specifically for components at different positions relative to the light source center. The correction amount varies locally depending on the component's position (distance and angle from center) and type, allowing accurate compensation for light source effects at each location while maintaining optimal overall illumination
Solution Approach 2:
The system changes parameters by measuring deviation for different component types and positions, then using these measured parameters to correct recognition accuracy. The correction amount is determined by component type, position coordinates, and distance from the light source center, allowing dynamic adjustment of recognition parameters based on local conditions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution improves the mounting accuracy of components by correcting deviations caused by light source effects, allowing for high-precision placement of components on circuit boards, even when multiple components are imaged together, thereby enhancing productivity and reducing errors.
Implementation Method 1
a camera (16) to take images of components (A to D) being held on suction nozzles (21) illuminated by a light source (64) from below
Data Source
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AI summary
Before starting production, measure the deviation amount of the recognized position of multiple components A to D being held by multiple suction nozzles 21 and memorize that measurement data using a memorizing means; then, during production, correct the deviation of the recognized position of components A to D being held on each suction nozzle 21 by reading the data for the recognized position deviation amounts from said memorizing means. For the measurement of the deviation amount of the recognized position it is preferable to, before starting production, to take an image of a component being held on suction nozzle 21 with the center of suction nozzle 21 and the center of the camera field of view aligned and to image process this image to recognize the position of the component; and also to move suction nozzle 21 to the position where the image is to be taken during production and to take an image of the component with the camera and vision process the image to recognize the position of the component; then to calculate the recognized position deviation amount as the difference between the distance that suction nozzle 21 was moved and the distance separating the two recognized position points.