Contact Soldering Research Articles

Development of the Regimes of Semiautomatic Contact Soldering

The influence of the soldering rod length on the contact soldering temperature has been studied. The results of investigations were taken as a basis for incorporating a high-speed semiautomatic regime of soldering integrated circuits with planar leads to multilayer printed circuit boards. It has been established that to ensure an optimum soldering temperature it is necessary to take account of the temperature of the soldering rod before soldering, its length and diameter, and the soldering time when the rod is short.

Thermophysical Characteristics of the Protective Coating of the Soldering Rod

An analytical dependence of the change in the soldering temperature on the material, thickness of the soldering rod protective coating, and the time of soldering is obtained. The relation derived allows one to ensure the needed temperature of contact soldering of electronic and electrical-engineering components and, consequently, their high quality.

The Results of Thermal Investigations in the Region of the Contact Soldering of Electronic Devices

It is shown that one of the most important parameters of soldering, which affects the quality of soldered joints, is its temperature. The temperature control of the soldering stations employed at the present time before soldering does not guarantee that the required temperature will be attained. The use of the relations proposed enables this drawback to be eliminated.

Femtosecond Micromachining of Ceramic Fibers for Electric Contact Soldering

In this report we demonstrate that using femtosecond laser pulses it is possible to create micronotches and micro-wells in conductive titanium dioxide (Magneli phase) ceramic. Fabricated microcavities were later used as support points for wire soldering in order to integrate ceramic fiber into electronic measuring circuit as a mechanical wear sensor. We show that with optimal cutting parameters laser-processed areas retain good conduction properties and have no impact on electric contact quality. Using galvanometric scanners together with high repetition rate femtosecond laser pulses it is possible to form such microcavities in times suitable for industrial needs.

Optimization of the required temperature of contact soldering of electronic devices

Experience in production of electronic devices shows that the quality of their manufacture depends primarily on the quality of the soldering operation. Among the factors infl uencing the quality of soldered joints (soldering time, quality of joined surfaces, size of the gap between them, used fl ux, solder composition), the soldering temperature is deciding [1]. From experience it follows that the required soldering temperature does not coincide, as a rule, with the temperature set on the equipment (heater, soldering rod) and the ambient temperature. The nonstationary temperature fi eld arises during soldering due to the nonequilibrium processes of heat conduction, heat emission, and convective heat exchange with the environment [2]. Therefore, the soldering temperature depends primarily on the geometrical and temporal conditions of the heat transfer processes. The required quality of soldered joints can be attained by optimal variation of these conditions. However, the large number of parameters infl uencing the processes under consideration makes the optimization problem diffi cult to solve [3, 4]. Moreover, printed circuit boards should be soldered, where possible, under unifi ed technological conditions, which follows from the condition of carrying out group soldering, as well as from the necessity of controlling the

Improvement of international standards for contact soldering in electronics

Proposals are made to improve international standards which can be used for correcting the currently valid and for developing new national standards.

The development of the physical fundamentals of contact soldering as a factor for reducing the number of defects in electronic devices

Automated control systems employ electronic components that are connected with a printed circuit board (PCB) by soldered joints. At elevated temperatures and with high vibration levels, soldering defects may occur that are characterized by the deterioration or complete loss of contact with the PCB, which can lead to the failure of the system. In this work, an approach is proposed to considerably improve the reliability of soldered joints.

Detection of Degradation Effects in Field-Aged c-Si Solar Cells through IR Thermography and Digital Image Processing

Due to the vast expansion of photovoltaic (PV) module production nowadays, a great interest is shown in factors affecting PV performance and efficiency under real conditions. Particular attention is being given to degradation effects of PV cells and modules, which during the last decade are seen to be responsible for significant power losses observed in PV systems. This paper presents and analyses degradation effects observed in severely EVA discoloured PV cells from field-aged modules operating already for 18–22 years. Temperature degradation effects are identified through IR thermography in bus bars, contact solder bonds, blisters, hot spots, and hot areas.I-Vcurve analysis results showed an agreement between the source of electrical performance degradation and the degradation effects in the defected cell identified by the IR thermography. Finally, an algorithm was developed to automatically detect EVA discoloration in PV cells through processing of the digital image alone in a way closely imitating human perception of color. This nondestructive and noncostly solution could be applied in the detection of EVA discoloration in existing PV installations and the automatic monitoring and remote inspection of PV systems.