Reflow Process Parameters Analysis and Reliability Prediction Considering Multiple Characteristic Values

As a major step surface mount technology, reflow process is the key factor affecting the quality of the final product. The setting parameters and characteristic value of temperature curve shows a nonlinear relationship. So parameter impacts on characteristic values are analyzed and the parameters adjustment process based on orthogonal experiment is proposed in the paper. First, setting parameters are determined and the orthogonal test is designed according to production conditions. Then each characteristic value for temperature profile is calculated. Further, multi-index orthogonal experiment is analyzed for acquiring the setting parameters which impacts the PCBA product quality greater. Finally, reliability prediction is carried out considering the main influencing parameters for providing a theoretical basis of parameters adjustment and product quality evaluation in engineering process

Reliability Sensibility Analysis of the PCB Assembly concerning Warpage during the Reflow Soldering Process

As a vital component of electronic products, the quality of the printed circuit board (PCB) assembly directly affects the applications and service life. During the reflow soldering process, the PCB assembly may suffer excessive warpage. Therefore, in order to avoid such a failure, this paper conducts the finite element simulation of the PCB assembly temperature change and the deformation process according to a theoretical model for heat transfer and then explores the causes of warpage and predicts the percentage of warpage that occurs during the reflow soldering. A reliability sensitivity analysis is creatively applied in the PCB assembly warpage study in order to uncover the quantitative influence of multiple factors with random errors on warpage. Moreover, the reliability calculation provides a theoretical basis for the allowable error range of geometric dimensions, material properties and process parameters of the PCB assembly. This research has a remarkable significance and is valuable to engineering in promoting quality and reliability, and increasing the yield of PCB assembly in mass production

Reflow Process Parameters Analysis and Reliability Prediction Considering Multiple Characteristic Values

As a major step surface mount technology, reflow process is the key factor affecting the quality of the final product. The setting parameters and characteristic value of temperature curve shows a nonlinear relationship. So parameter impacts on characteristic values are analyzed and the parameters adjustment process based on orthogonal experiment is proposed in the paper. First, setting parameters are determined and the orthogonal test is designed according to production conditions. Then each characteristic value for temperature profile is calculated. Further, multi-index orthogonal experiment is analyzed for acquiring the setting parameters which impacts the PCBA product quality greater. Finally, reliability prediction is carried out considering the main influencing parameters for providing a theoretical basis of parameters adjustment and product quality evaluation in engineering process

Badanie modelu niezawodności ruchów sekwencyjnych oraz propozycja rozwiązania

The missions of weapon systems are becoming increasingly complex. Thus, more mechanism motions than one are required to complete one mission. Under such conditions, a sort of mission has emerged, that needs a few mechanism motions to be executed in sequence. This means that the mission is not completed until all the motions have been executed successfully in strict sequence. This sequence motion system can be considered as a traditional series system with the motions treated as subsystems. Then, the system reliability can be analyzed with the traditional series system reliability method. However, this method cannot fully reflect the characteristics of a sequence. In this work, a reliability model of sequence motions and its solving idea are proposed. In this reliability model, the influence factors of each motion are included. Particularly, the performance function of the former motion is regarded as just one of the influence factors of the next motion, which is the most significant feature for the sequence motion system. Afterward, a solving idea with characteristics of a gradually shrinking sample space is proposed based on Monte-Carlo simulation. Finally, the reliability model of sequence motions and its solving idea are illustrated with a case study on the automatic chain shell magazine sequence motions of a self-propelled artillery.Misje systemów uzbrojenia stają się coraz bardziej złożone. Często, jedna misja wymaga wykonania przez układ zmechanizowany więcej niż jednego ruchu. W artykule omówiono misję, w której układ zmechanizowany wykonuje sekwencję kilku ruchów. Misja w takim układzie nie zostanie ukończona, dopóki wszystkie ruchy nie zostaną prawidłowo wykonane w ściśle określonej kolejności. Taki układ sekwencyjnych ruchów można rozważać w kategoriach tradycyjnego systemu szeregowego, traktując poszczególne ruchy jako jego podsystemy. Wówczas, niezawodność systemu można analizować za pomocą tradycyjnej metody analizy niezawodności systemów szeregowych. Jednak, metoda ta nie jest w stanie w pełni odzwierciedlić charakterystyki sekwencji. W niniejszym artykule zaproponowano model niezawodności ruchów sekwencyjnych oraz jego rozwiązanie