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Rework and Repair Procedures of Selected Components and LED on Various Types of PCBs.
Pospíšil, Tomáš ; Ondřej, Klemš (referee) ; Starý, Jiří (advisor)
This work deals with technology of rework and repairs of electronic soldering assemblies. The work is primarily focused on the rework and repairs of electronic soldering assemblies with the light emitting diode. The theoretical part describes the technological methods of soldering and reworking of electronic assemblies, their diagnostics, evaluation of their influence on reliability and functional properties. The practical part is focused on the real application of technological procedures of rework and repairs, their testing and evaluation. Furthermore there is described and tested the influence of thermal load during soldering on the properties of light emitting diodes.
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Optimization of surface treatment of stainless steels
Mačátová, Lucie ; Žák, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
The project deals with the processes of degreasing industry and testing new laser cleaning process, which has been experimentally verified and tested in the production process. Project also deals with soldering in general as a technology of joining metals. Included are the main components of the soldering, such as solder, flux, the types of connections and their use, ways of soldering and last but not least the soldering corrosion-resistant steel.
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Reliability of LED Panels Solder Joints
Šimon, Vojtěch ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
Thesis is focused on the effect of heating factor on quality of solder joints. In theoretical part is solved reflow soldering technology, problematice of solder paste choice or criteria of soldering profile setting. The practical part is dedicated to demonstrating the impact of heating factor on solder joint quality. There are used X-Ray analysis, microsections and electron microscopy. In the final part of this thesis are summarized knowledge from theoretical part and experimental obtained results to defend of next steps in diploma thesis.
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Optimization of surface treatment of stainless steels
Mačátová, Lucie ; Žák, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
The project deals with the processes of degreasing industry and testing new laser cleaning process, which has been experimentally verified and tested in the production process. Project also deals with soldering in general as a technology of joining metals. Included are the main components of the soldering, such as solder, flux, the types of connections and their use, ways of soldering and last but not least the soldering corrosion-resistant steel.
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Connecting methods used in automotive industry
Gregora, David ; Müller, Miroslav (advisor) ; Valášek, Petr (referee)
This bachelor thesis is focused on analyzing methods of joining sheets in the automotive industry. In the thesis are theoretically analyzed and described the various methods that are most often used for connecting plates in the automotive industry. It stated their principles, advantages and disadvantages. Selected methods are welding, soldering, adhesive bonding, riveting and clinching. This thesis works with methods that are used in the automotive industry for a long time, but also methods that are relatively new and brings to the production benefits that are mainly increasing productivity and lowering production costs and the weight of the entire body.
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Mini reflow oven
Pavelka, Radek ; Jelínek, Aleš (referee) ; Burian, František (advisor)
This thesis is aimed to design a small oven for PCB soldering using the reflow method. It contains description of the oven’s construction, it’s thermodynamic parameters and the design of the control and power unit PCB as well as their control software. A remote PC control and monitoring application is also a part of this thesis.
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Mechanical Properties of solder joint
Meliš, Josef ; Starý, Jiří (referee) ; Stejskal, Petr (advisor)
This thesis deals with the differences between the mechanical properties of surface conditionings of the printed circuit boards and various types of soldering pastes. The practical part of the thesis describes all the steps necessary to conduct the experiment. The experiment will evaluate the measured mechanical strength of the solder joint for each surface conditioning, the types of solders, the increase in thickness of the intermetalic layer during long-term aging and the change in the structure of the solder joint.
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THE APPLICATION OF NANOMATERIALS FOR LEAD FREE SOLDERS DEVELOPMENT
Pešina, Zbyněk ; Pinkas, Jiří (referee) ; Spousta, Jiří (referee) ; Sopoušek, Jiří (advisor)
The present dissertation is motivated by the search for alternatives of lead-free soldering by nanoparticles of metals and their alloys. The research focuses on the possibility of replacing lead-free solders by nanoparticles. This issue is currently being addressed by the use of lead-free solders but their properties are not entirely equivalent to properties of lead-tin based alloys. The theoretical part of the dissertation first summarizes up-to date knowledge on the development of lead-free alloys currently used for soldering in the electronics. The work compares these lead-free solder candidates with previously used Pb-Sn alloys. The second section of the theoretical part is devoted to nanotechnology that offers possible solutions of problems associated with the use of lead-free solders. The text contains a description of the properties of nanocrystalline materials in comparison with those of compact alloys having the same chemical composition. The possibility of preparation of nanoparticles and potential problems associated with small particle sizes are also presented. Introduction of the experimental part focuses on the preparation of nanoparticles of pure metals and alloys by chemical and physical ways as well as on an instrumentation for characterisation and analysis. Attention is focused on the silver in nanoparticle form that exhibits the low temperature sintering effect, which is thermally activated by decomposition of oxide envelope covering the Ag nanoparticles. This factor is critical for low-temperature sintering and thus also for possible future applications. The thermal effects of the low sintering process were studied by methods of thermal analysis. The preparation of the Cu / Ag nano / Cu joints was carried out in-situ in inert atmosphere and under the action of atmospheric oxygen. In both cases varying conditions of thermal treatment were used. The cross sections of the prepared joints were then used for the metallographic analysis of the local mechanical properties of the resulting silver layer, for the chemical composition evaluation of the resulting layers of the joint, and for the microstructure study. Strength characteristics are represented by testing shear strength of individual joints.
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Laser brazing in the car industry
Podstavek, Michal ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
The project elaborated in frame of engineering studies of the subject M-STG Mechanical Engineering describes elementary methods of joining in the automotive industry. Moreover, it inquires into optimization of laser brazing on the back cover ŠKODA Superb. During the optimization of the process six samples were designed, and the adjustment of the brazing parameters were performed. Consequently, the samples were evaluated by tensile and metallographic tests. Finally, EDS analysis was performed and visual assessment as well.
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