Intelligent detection of solder joints on printed circuit boards

2011 ◽  
Vol 19 (9) ◽  
pp. 2154-2162 ◽  
Author(s):  
谢宏威 XIE Hong-wei ◽  
张宪民 ZHANG Xian-min ◽  
邝泳聪 KUANG Yong-cong ◽  
欧阳高飞 OUYANG Gao-fei
Keyword(s):  
Printed Circuit Boards ◽  
Solder Joints ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Intelligent Detection

Stress Analysis of Printed Circuit Boards With Highly Populated Solder Joints and Components: A Micromechanics Approach

1996 ◽  
Vol 118 (2) ◽  
pp. 87-93
Author(s):  
K. X. Hu ◽  
Y. Huang ◽  
C. P. Yeh ◽  
K. W. Wyatt
Keyword(s):  
Stress Analysis ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
Effective Properties ◽  
Mechanical Analysis ◽  
Computational Effort ◽  
Circuit Boards ◽  
Element Analysis ◽  
Printed Circuit ◽  
Board Level

The single most difficult aspect for thermo-mechanical analysis at the board level lies in to an accurate accounting for interactions among boards and small features such as solder joints and secondary components. It is the large number of small features populated in a close neighborhood that proliferates the computational intensity. This paper presents an approach to stress analysis for boards with highly populated small features (solder joints, for example). To this end, a generalized self-consistent method, utilizing an energy balance framework and a three-phase composite model, is developed to obtain the effective properties at board level. The stress distribution inside joints and components are obtained through a back substitution. The solutions presented are mostly in the closed-form and require a minimum computational effort. The results obtained by present approach are compared with those by finite element analysis. The numerical calculations show that the proposed micromechanics approach can provide reasonably accurate solutions for highly populated printed circuit boards.

Prognostic Health Monitoring Method for Fatigue Failure of Solder Joints on Printed Circuit Boards Based on a Canary Circuit

2013 ◽  
Author(s):  
Kenji Hirohata ◽  
Yousuke Hisakuni ◽  
Takahiro Omori ◽  
Tomoko Monda ◽  
Minoru Mukai
Keyword(s):  
Fatigue Failure ◽  
Health Monitoring ◽  
Failure Probability ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
High Density ◽  
Probability Estimation ◽  
Circuit Boards ◽  
Printed Circuit ◽  
High Density Packaging

Continuing improvements in both capacity and miniaturization of electronic equipment such as solid state drives (SSDs) are spurring demand for high-density packaging of NAND-type flash memory mounted on SSD printed circuit boards. High-density packaging leads to increased fatigue failure risk of solder joints due to the decreased reliability margin for stress. We have developed a failure precursor detection technology based on fatigue failure probability estimation during use. This method estimates the cycles to fatigue failure of an actual circuit by detecting broken connections in a canary circuit (a dummy circuit of daisy-chained solder joints). The canary circuit is designed to fail earlier than the actual circuit under the same failure mode by using accelerated reliability testing and inelastic stress simulation. The statistical distribution of the strain range of solder joints can be provided by Monte Carlo simulations based on the finite element method and random load modeling. A feasibility study of the failure probability estimation method is conducted by applying the method to a printed circuit board on which a ball grid array (BGA) package is mounted using BGA solder joints. The proposed method is found to be useful for prognostic health monitoring of solder joint’s fatigue failure.

Failure Analysis of No-Clean and Water-Clean Solder Joints 0.4 mm Pitch, 256-Pin Plastic Quad Flat Pack

1994 ◽  
Vol 116 (3) ◽  
pp. 184-190 ◽  
Author(s):  
R. K. Govila ◽  
Y.-H. Pao ◽  
C. Larner ◽  
J. Lau ◽  
S. Twerefour ◽  
...  
Keyword(s):  
Eutectic Composition ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
Quantitative Comparison ◽  
Circuit Boards ◽  
Micro Structure ◽  
Printed Circuit ◽  
Qualitative And Quantitative ◽  
Solder Interface ◽  
Scanning Electron

Printed circuit boards populated with twenty-five 0.4 mm pitch, 256-pin plastic quad flat packs (QFP) containing no-clean and water-clean solder joints were subjected to thermal cycling in order to induce thermal fatigue failure. QFPs failed from a minimum of 0.27 cycle to a maximum of 5310 cycles. Solder joints in both types of units were examined in the scanning electron microscope, and a relative comparison of the extent of fatigue damage is presented. The failure associated with cracking in the eutectic composition Sn/Pb solder initiated at the stress concentration sites. Crack propagation continued either along the pin-solder interface or solder-pad interface and ultimately resulted in the separation of the pin/pad junctions. In addition, a qualitative and quantitative comparison of the resulting solder micro-structure and the failure mode between the no-clean and the water-clean QFP solder joints was made and discussed.

An Approach to Detection of Solder Joints on Printed Circuit Boards

2013 ◽  
Vol 712-715 ◽  
pp. 2364-2367
Author(s):  
Xiao Su Tong
Keyword(s):  
Euclidean Distance ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Circuit Board ◽  
Image Similarity ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Optical Inspection ◽  
Different Types

To automate present Automatic Optical Inspection (AOI) systems, an intelligent method based on lightness analysis for solder joints detection is proposed in this paper. Firstly, the image taken from real printed circuit board (PCB) is preprocessed and segmented. Then, we compute the image similarity by calculating the Euclidean distance. If the similarity exceeds the threshold, we extract the lightness of solder joints by converting between RGB color mode and HLS color mode. Lastly, all the defects of solder joints are classified into several different types according to their lightness appearances. Experiment results show that the method deduced in this paper can detect accurately solder defects from different patches.

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