Solder Paste Defect Re-Evaluation After SPI False Rejects
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Solution Overview
Problem
The existing solder paste inspection (SPI) systems in surface mount technology (SMT) have low accuracy, leading to high over-kill rates and manual re-inspection requirements, which consume manpower and reduce production efficiency.
Innovation Solution
A defect detection method and system that includes a SPI machine and a terminal device for re-evaluating products initially identified as defective, using image processing to determine the type of defects in solder paste printing, thereby reducing over-kill rates and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the detection standard is set high to improve manufacturing precision, then the over-kill rate increases, but productivity decreases due to increased manual inspection requirements
Solution Approach 1:
The patent segments the inspection process into two stages: automated SPI detection for initial screening and selective manual re-inspection only for products that fail the automated detection. This segmentation allows the system to maintain high detection standards while minimizing manual inspection to only necessary cases, thereby resolving the contradiction between precision and productivity
Solution Approach 2:
The patent introduces an intermediary mechanism (the automated SPI detection system with specific algorithms) that acts as a mediator between high detection standards and productivity. The intermediary filters out most products automatically, allowing high standards to be maintained without requiring manual inspection for every product, thus resolving the contradiction
2Productivity
If the detection standard is set low to improve productivity, then the over-kill rate decreases, but measurement precision deteriorates leading to missed faulty products
Solution Approach 1:
The patent implements dynamic detection standards where the system adaptively adjusts inspection strictness based on product characteristics and defect patterns. The detection algorithm dynamically optimizes parameters to maintain high measurement precision while avoiding excessive over-kill rates, thus resolving the contradiction between productivity and precision
3Measurement precision
If manual re-inspection is increased to improve measurement precision, then detection accuracy improves, but loss of time increases due to additional inspection steps
Solution Approach 1:
The patent applies partial action by performing manual re-inspection only on a selective subset of products that fail automated detection, rather than inspecting all products manually. This partial application of manual inspection maintains high measurement precision for critical cases while minimizing time loss, resolving the contradiction between precision and time
Data Source
AI summary
A defect detection method includes: obtaining an image of a first defective block output by the SPI machine; wherein the first defective block is a solder paste block that is not qualified for printing after being detected by the SPI machine; processing the image of the first defective block; detecting whether solder paste printing in the first defective block is qualified; and determining that the first defective block is a second defective block and determining a defect type of the first defective block when the solder paste printing of the first defective block is not qualified. A terminal device and a non-volatile storage medium therein, for performing the above-described method, are also disclosed.