Papers by Keyword: Surface Mount Technology (SMT)

Abstract: An X-ray inspection machine image detection system is designed by making use of the software Visual C++ 6.0, in which a lot of noise in the X-ray image are filted out by using corrosion algorithms and median filtering method. A analysis software of the bridging of the solderjoints, weld situation is designed,which can real-time display and zoom the image of solder joint inspection, and can alarm.

Abstract: The complexity of Printed Circuit Boards (PCBs) has increased dramatically over the last three decades with the development of surface mount technology (SMT). The typical manufacture of rigid multilayer PCB contains many process procedures, which makes manufacture and application much more challenges. This paper focuses on some typical PCB related failures. Recommendations are provided on optimizing PCB manufacture process and material application. Microvia crack, black pad, galvanic attack, pad design, conductive anodic filament and pad crater are presented in detail.

Abstract: The principles of the Surface Mount Technology (SMT) product character segmentation and its technology could be described as following: SMT product character image is obtained by image sampling equipment and its ideal binary images is got after image processing. In order to segment the SMT product character effectively, a novel character segmentation algorithm is proposed based on contour feature. Three kinds of information are extracted, one is the up contour feature, another is the under contour feature, the third is the width and the height of the image. Then the position of character segmentation is determined according to the width and height of single character, and character segmentation can be accomplish according to its up contour feature and under contour feature. By analyzing the test result, the proposed approach has excellent properties in character segmentation.

Abstract: This paper introduces the content included in two-dimensional quality information of the SMT solder joint and illustrates the basic principle of extracting two-dimensional information quality of SMT solder joint .By explaining the basic theory and principles and combining with example, the implemention of extracting methods and steps are discussed.The extraction algorithms carry out in VC + + programming, And this lay a good groundwork for follow-up intelligent analysis of solder joint.

Abstract: By determining membership function of the input parameters and selecting defuzzification method, the evaluation model which can be used to intelligent analyzing the causes of SMT solder joint defects was set up. The fuzzy neural network was trained by using the output variables of the training samples from intelligent discrimination as the input variables of training samples of fuzzy neural network. The fuzzy neural network was tested by using the output variables of the testing samples from intelligent discrimination as the input variables of testing samples of fuzzy neural network. The results show that by using the evaluation model the cause of SMT solder joint defects can be analyzed intelligently and the results of intelligently analysis are reasonable, the evaluation model can be used practically.

Abstract: In this paper, taking workshop scheduling of SMT product manufacture system for object, the conception of resource cost is incorporated with Petri Nets. The workshop scheduling model of SMT product manufacture system is build based on transition timed Petri Nets (TC-TPN). ω1 proportion of processing cost, ω2 proportion of processing time, ω3 mutation factor are chosen as the key factors using the improved heuristic A* scheduling algorithm. The result shows that: considering the processing time preference, when ω1=0.7, ω2=0.2, ω3 =0.1, the processing time is reduced by 5.83%, 3.45%, the processing time is decreased by 6.14% and 2.94%; however, considering the processing cost preference, when ω1=0.1, ω2=0.8, ω3 =0.1, the processing time is reduced by 1.94%, 0.86%, the processing time is decreased by 8.06% and 7.52%.

Abstract: A stencil printing process (SPP) optimization problem is studied in this paper. Due to the limitation that neural network requires a large number of samples for the accurate model fitting, a two-stage SPP optimization method is proposed. The design interval can be reduced with small sample by using neural network. In this reduced design interval , response surface method is adopted to obtain the accurate mathematical SPP model. The concept of confidence level is introduced to make the proposed model robust. An interactive method is used to solve the model. The proposed method is compared with the one-stage optimization method and the results show that the proposed method achieves a better performance on each objective.

Abstract: Pseudo solder is one kind of familiar solder joint defect, and it is very difficult to be detected in surface mounted technology. Reduce the pseudo solder is viewed as one of effectively way to keep the quality of solder joints. In this manuscript, the quality of component, solder paste printing process, mounting processing, reflowing process, solder material are analyzed to illustrate the cause of pseudo solder in surface mounted technology. Based on the five factors, a pseudo solder model is built for IC component. In the pseudo solder model, its parameters are used corresponding to the cause of pseudo solder, and their values are used to evaluate the degree of satisfaction based on the SMT technological process. Experiments results show that parameters of the pseudo solder model can illustrate the cause of pseudo solder effectively.

Abstract: We present an approach to recognizing characters in surface mount technology (SMT) product. An improved SMT product character recognition method is proposed which can obtain a good recognition rate. Some appropriate image processing algorithms, such as Gray processing, Low-pass Filter, Median Filter, and so on, are used to eliminate the noise. Then, Character image is obtained after character segmentation and character normalization. Finally, a three-layer back propagation (BP) neural network module is constructed. In order to improve the convergence rate of the network and avoid oscillation and divergence, the BP algorithm with momentum item is used. As a result, the SMT product character recognition system is developed. Experimental results indicate that the proposed character recognition can obtain satisfactory character-recognition rate and the recognition rate reached over by 98.6% when the hidden layer of BP neural network module has 20 nodes.

Abstract: This paper proposes an effective method to determine the optimal parameters settings of reflow soldering profile and helps reduce the try-and-error time in practical application. Due to the complex nonlinear relationship between reflow thermal profile and process parameters in this problem, BPNN is adopted to establish the model for description of this intricate relationship between inputs and outputs. According to the requirements of the reflow soldering profile, GA is used to calculate the best input parameters with its strong global research ability. Thus, a combined model with BPNN and GA is proposed for parameters optimization and contributes to reduction of decision time of input parameter for reflow soldering profile. In addition, a case study is given to prove the accuracy of the proposed method.