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Reliability of Lead-free Solders and the Selected Methods to Estimate its Lifetime
Švecová, Olga ; Kolařík, Vladimír (referee) ; Urbánek,, Jan (referee) ; Šandera, Josef (advisor)
The doctoral thesis is focused on reliability of lead-free solder SAC 305. Knowledge in the field of fatigue models used in determining the lifetime of solder joints are observed in this thesis. Also such methods of predicting reliability as numerically-analytical methods or reliability experimental tests are mentioned. Practical results of reliability measurement are presented. Experimental data served as the foundation for determining empirical coefficients for the fatigue model based on deformation induced by creep of the solder, which was implemented in the ANSYS environment. Results from different methods were compared and conclusions discussing the suitability of the presented prediction methods are formulated.
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Investigation of Reliability for Solder Joints in Nitrogen Atmosphere
Šefara, Petr ; Otáhal, Alexandr (referee) ; Szendiuch, Ivan (advisor)
This thesis examines the inuence of nitrogen atmosphere on the quality of the solder joint lead-free solder paste. For the solder paste were measured and set temperature proles. Thesis includes the implementation and measurement of samples in a protective nitrogen atmosphere and without a protective atmosphere. These measurements are compared, and the conclusions were drawn for the inuence of nitrogen atmosphere. The reliability and the quality of the soldered joints were investigated.
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Termomechanical reliability soldered connections in electronic
Novotný, Václav ; Psota, Boleslav (referee) ; Šandera, Josef (advisor)
The diploma thesis deals with the sphere of solder joints reliability. The narrower focus is use of lead-free solder alloy SAC305 in the production process and parameters of its reliability. The text describes the main factors, which have the influence on the reliability of solder joints under conditions of thermal cycling. These factors also relate with choice of substrates and technological processes of preparation, which are characterized and described. Another part is devoted to estimating the reliability of soldered connections and are listed the fatigue model to estimate reliability. These fatigue models are categorized based on different physical mechanisms that operate in the soldered joints during operation. Based on the comparison of different models is selected the most appropriate model and in conjunction with simulation in ANSYS is estimated reliability. For this purpose is selected soldered connection of the FR-4 substrate and ceramic substrate via SMD component. They are manufactured test kits and subjected to conditions of temperature cycling. Results obtained from experimental measurements are compared with results obtained by simulation and calculation.
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Optimization of soldering process in the production of instrument transformers
Šula, Matěj ; Schnederle, Petr (referee) ; Szendiuch, Ivan (advisor)
This diploma thesis deals with the soldering process in manufacturing instrument transformers. It summarizes the knowledge of soldering process, lead-free alloys and test methods selected solder joint. In the practical part is the analysis the manufacturing process in terms of soldering operations, testing of selected lead-free alloys, which are considered as a replacement for lead-based alloy - now used in the manufacturing process. The conclusion is optimized manufacturing process to reduce operating costs and improve quality.
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