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In the work presented the potential of a pyrometric process control during laser beam soldering will be enhanced. Primarily we have developed a processing head with an integrated up-to-date pyrometric sensor conditioned for the temperature range of soft soldering. Using high speed photography we have analysed the detected secondary emissions during laser beam soldering and correlated the acquired pyrometric signals of process emissions with processes sequencing. Finally we named different strategies and control methods to achieve reliable high quality solder joints implementing a pyrometric process control

Определение деформаций провода обмоток трансформатора собственным магнитным полем

Приводится рассмотрение продольных и поперечных деформаций проводника обмотки трансформатора, вызванных током короткого замыкания. Приводятся полезные соотношения, позволяющие оценить удлинения и сдвиг проводников в обмотке при известном токе. Приводится пример расчета распределения пондеромоторных сил для проводников обмотки трансформатора круглого и прямоугольного сечения

Влияние относительной ширины зубчатых колес на объем зуборезных работ

In order to optimize the soldering process of laserbars onto heatsinks with Indium solder, several investigations have been made. First the growth of the Indium oxide film is examined. With this knowledge four different reduction methods are selected. Formic acid as a wet chemical reduction, a plasma activated Hydrogen/Argon gas, a gas enriched with formic acid, and a protective layer of Gold were investigated and compared for an optimized reduction of the oxide film of the Indium solder. A cross section of the solder interface after the soldering process is made in order to see the distribution of the metals. High diffusion of the solder with its contact partners is a sign of a good connection. Enough pure Indium has to be available after the soldering process in order to use its creek properties to reduce the mechanical stress in the laserbar

Ректор ТПИ А. А. Воробьев - изобретатель электроимпульсного способа разрушения горных пород

Представлена история создания электроимпульсного способа разрушения горных пород ректором ТПИ А. А. Воробьевым

Sustainable Campus Community Engagement

Laser metal deposition (LMD) was applied to deposit Inconel 718 metal matrix composites reinforced with TiC particles. The influence of laser energy input per unit length on constitution phases, microstructures, hardness, and wear performance of LMD-processed TiC/Inconel 718 composites was studied. It revealed that the LMD-processed composites consisted of γ Ni-Cr solid solution matrix, the intermetallic precipitation phase γ′, and the TiC reinforcing phase. For the laser energy input per unit length of 80-120 kJ/m, a coherent interfacial layer with the thickness of 0.8-1.4 μm was formed between TiC reinforcing particles and the matrix, which was identified as (Ti,M)C (M=Nb and Mo) layer. Its formation was due to the reaction of the strong carbide-forming elements Nb and Mo of the matrix with the dissolved Ti and C on the surface of TiC particles. The microstructures of the TiC reinforcing phase experienced a successive change as laser energy input per unit length increased: Relatively coarsened poly-angular particles (80 kJ/m) - surface melted, smoothened TiC particles (≥100 kJ/m) - fully melted/precipitated, significantly refined TiC dendrites/particles (160 kJ/m). Using the laser energy input per unit length ≥100 kJ/m produced the fully dense composites having the uniformly dispersed TiC reinforcing particles. Either the formation of reinforcement/matrix interfacial layer or the refinement in TiC dendrites/particles microstructures enhanced the microhardness and wear performance of TiC/Inconel 718 composites

О некоторых особенностях структуры участков коры выветривания серпентинитов Кемпирсайского массива

New diode laser devices use the modular character of diode lasers to form beam shapes that are adapted to the processing task. In this paper cutting and welding applications of these tools are presented. A linear laser line is applied for the cutting-to-length of coil material. Diode laser modules that form an annular laser spot are utilized for optical flame cutting of steel material and simultaneous welding of annular seams. Furthermore, cutting of thin materials with a diode laser cutting plotter device is demonstrated. Moreover, new results of welding experiments with commercial diode lasers are presented

Общие вопросы развития электроприводов современных металлорежущих станков

Besides their high efficiency and compact dimensions high power diode laser systems feature the modularity to from different beam shapes adapted to the respective application. So apart from the development of diode laser systems concerning the increase of output power and beam quality, another approach is the special assembling of individual diode laser bars to build up modular systems for new direct diode applications. Despite the limited but often sufficient beam quality of this modular approach it offers many advantages in applications like simultaneous polymer welding, laser cutting, laser welding and hardening of metals

Об определении оптимальных расстояний между разведочными выработками в связи с различными размерами участков и анизотропностью тел полезных ископаемых

The main challenge to address single emitters in a high-power diode-laser-bar is the thermal and electrical management to avoid crosstalking. Especially p-side up assembly leads to increasing thermal influence of neighboring emitters due to the low thermal conductivity of GaAs. Electro-magnetic fields inside and outside the laser-bar, for example caused by high frequency modulation (10 MHz) at a high current (up to 1 A), induce voltages into neighboring electrical circuits, hence the output power of neighboring emitters can be affected

Бесконтактный односекционный микродвигатель постоянного тока

Ultrafast lasers have found widespread applications in science and industry. In order to increase the throughput in micromachining and to reduce the measurement time in scientific applications, the average power of these laser sources needs to be increased. Ultrafast laser sources of high average power at moderate cost, high reliability and flexible repetition rate are essential for the transfer of femtosecond technology to industry

Роль дизъюнктивных нарушений в распределении, формировании и разрушении залежей газа на Малохетском валу (северо-восток Западно-Сибирской низменности)

High reliable diode laser pump modules are essential for free-space optical telecommunications. Besides the reliability, low mass and small dimensions, radiation-hardness and low power-consumption are requirements to be met for space applications. A diode laser module suited for pumping Nd:YAG lasers for optical intersatellite links has been developed. The module consists of two diode laser bars overlaid by a polarization beam splitter to increase the system's reliability. Each diode laser bar consists of six emitters. If the integrated photodiode detects the failure of one bar, the second, substitute bar is switched on and can fully sustain all module functions. To equalize the beam quality of the diode laser bar, a pair of micro step mirrors is used for each bar. The laser beam is focussed on the entrance of a d=200 µm, NA=0.22 fiber. Both the coupling efficiency and the accuracy of the mounting of the diode laser components have been analyzed by raytracing. Passive cooling has been chosen because liquid chilling systems are unsuitable for space applications. To evaluate the effects of different heat sink materials and to predict the temperature drop over the module, a 3D finite element analysis for the steady-state temperature distribution of the module has been performed. The optical output power of the module described above amounts to 2,8 W with one bar operating derated to 0.5x maximum current, and the whole unit fits in a housing of 78 x 50 x 24 mm. Further developments will lead to a more compact design and a smaller fiber diameter