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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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Analysis of Defects on PCB Using X-RAY
Mlýnek, Martin ; Vala, Radek (referee) ; Řihák, Pavel (advisor)
This thesis is focused on BGA packages and fault detection after rework using X – Ray. There is a description of BGA packages by carrier substrate, techniques of connecting on chip, from mounting packages to repair printed circuit boards (hereafter PCB). Thesis summarizes description of defects, which are created after rework process. There is also description of X – Ray as method for analyzing defects. X – PLANE method used to detect internal structure of BGA packages and it was confirmed by microsection and by software for reconstruction. Description of automatic and manual measurement is follow.
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Testing of Solders in Protection Atmosphere
Vala, Radek ; Jankovský, Jaroslav (referee) ; Szendiuch, Ivan (advisor)
The project deals with the overall design and construction of equipment called the desiccators for brazing in a protective atmosphere. The device was designed and manufactured cooling and heating element. For the soldering various temperature profiles have been defined and adjusted, as for SnPb as well for lead-free solders. There was a realization of samples were measured and analyzed. Finally were realized micro sections for lead free solder.
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Laser diode soldering
Straka, Michal ; Holík, Milan (referee) ; Stejskal, Petr (advisor)
This work deals with the laser diode soldering. The theoretical part summarizes general and acquired findings about soldering technology and materials that occur in this process. It also describes factors that affect the reliability of solder joints. It is closely focused to the shaping of the solder joint and structure of intermetallic layer. The practical part of this work is focused on the design of equipment for laser diode soldering and subsequent shaping of the samples. The quality of soldered joint is compared against the quality of joint created using re-flow technology - remelting in in-line smelter. The structure and thickness of the intermetallic layer, the number and shape of the voids in the solder joints are compared.
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Design of Soldering Gun
Běhal, Tomáš ; Křenek, Ladislav (referee) ; Ondra, Martin (advisor)
This bachelor thesis deals with the design of transformer soldering gun. The product is analyzed from the historical, technical and design ways at first. Subsequently, the new design of this product is proposed, with respect to ergonomic, technical, aesthetic and psychological aspects.
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Unconventional Metals Hardsurfacing Technologies
Krejčí, Vojtěch ; Šárka,, Šimůnková-Houdková (referee) ; Čelko, Ladislav (advisor)
The main objektive of the bachelor thesis is to evolve problems of metalic surface welding and to implement the basic partition of the most expanded used technologies of surface welding. Sometimes we can see the term deposition metalic surface welding too but in practice is used technical term metalic surface welding. The introdution includes the basic acquaintance with problems and the characterization of the proces of surface welding including the summary of its advantages and disadvantages. In other chapters we aim on individual technologies of surface welding, its principle and using in technical practice. Simultaneously is worked out the overview of already unused or minimally used technologies of surface welding. After the presentation of individual technologies follows the section dealing with partition of materials used for surface welding by the basic material as well as surface welding materials at the present technical practice. In the experimental section of thesis follows selected examples of using the presented technologies of surface welding in practice at present.
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Structual welding of aluminium alloy
Blahák, Petr ; Hála, Michal (referee) ; Kubíček, Jaroslav (advisor)
The project elaborated in frame of engineering studies branch 2303R002 presents a project that contains welding a structure made of aluminium alloy. There were two usable methods selected, based on literal study of welding aluminium alloys, TIG welding and friction welding, and these were compared with alternative methods of joining, hard soldering and bonding. A work procedure was made for TIG method, soldering and bonding and four experimental joins were made thereafter. Project compares these methods mainly in economical way, also in way of technological difficulties and in way of observance the strength of base materials. Project also deals with problems with lowering strength of base material in heat affected area, burn out of thin material, tendency of aluminium to fill with hydrogen, quick oxidation and consequent hard surface layer emerging on the aluminium.
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Properties of conductive connections
BJALKOV, Pavel
In the introduction of the thesis there are described and explained basic terms used in designing and making printed circuits including the description of technological environment. The thesis deals with the description of jointing and the technology of assembling electronic components with boards of printed circuits. Further it also contents various types of tests of conductive joints quality and technologies of mounting parts in manufacturing process with examples of possible mistakes occurring during mounting and soldering the parts on boards of printed circuits
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