Soldering Technique Research Articles

The development and formation of soldering technique on the bronze ritual vessel casting of the Shang and Zhou Dynasties

Abstract This paper concerns the development of soldering in early China. Soldering requires the use of an additional heating of metal to join two or more existing metal items together. The paper defines the different soft and hard soldering materials. It also describes the evolution from joining two pieces, an animal head and a vessel with additional pour of bronze as an extension of the casting process. The next step was the use of hard solder, using bronze or copper related materials. There were two ways to join the existing bronze sections: the most common was “tenon soldering”. Less common but equally significant was “injection soldering”. In the late Spring-and-Autumn Period, soft soldering with tin and lead was developed. This step allowed much more extravagant decoration of bronzes, leading to new bronze vessel styles and also to much greater sub-division of labor in the production process.

Robot-assisted laser tissue soldering system.

Fast and reliable incision closure is critical in any surgical intervention. Common solutions are sutures and clips or adhesives, but they all present difficulties. These difficulties are especially pronounced in classical and robot-assisted minimally-invasive interventions. Laser soldering methods present a promising alternative, but their reproducibility is limited. We present a system that combines a previously reported laser soldering system with a robotic system, and demonstrate its feasibility on the incision-closure of ex-vivo mice skins. In this demonstration, we measured tearing forces of ~2.5N, 73% of the tearing force of a mouse skin without an incision. This robot-assisted laser soldering technique has the potential to make laser tissue soldering more reproducible and revolutionize surgical tissue bonding.

Evaluation of Soldered Joints of Two Base Metal Ceramic Alloys: Supercast and Minalux

Background: Different soldering techniques have a variety of applications in dentistry. One of the most important uses of soldering is to join multiple-unit fixed partial dentures together. In this Study, two base metal alloys (Supercast and Minalux) were soldered and their tensile, compressive and flexural strengths were measured and compared to each other. Materials and methods: In this in-vitro study, an aluminum pattern was made by a milling machine according to ASTM (American Society for Testing Material). Eighteen acrylic resin Patterns were duplicated by flasking using putty indices according to the original aluminum pattern. Acrylic resin patterns were divided into two groups of nine and each group was cast with two different alloys named Supercast and Minalux. All eighteen metal rods were separated by 0.008-inch disc and soldered with Vera-solder by means of gas-oxygen torch. Three patterns of each alloy were selected for each of the compression, tensile and flexural tests. Tensile strength was measured by Instron a universal machine and flexural and compression strengths were measured by Dartec machine. Statistical analysis was done by Mann - Whitney test. Results: The mean tensile, flexural and compressive strengths for supercast alloy was 347.6, 44.01 and 1014.8MPa respectively and the mean for tensile, flexural and compressive strengths for Minalux alloy was 350.03, 51.70 and 938.17 MPa respectively. Statistical analysis showed no significant differences between the two alloys in all the three mentioned tests. (p>0.05) Conclusion: Tensile, flexural and compressive strengths of the two soldered alloys, Minalux and supercast, showed no significant differences. Minalux is an alloy manufactured in Iran with the advantage of not including Beryllium, a cariogenic element, as one of the ingredients of the alloy; therefore, it is suggested that Minalux be used instead of supercast in soldering procedures in fixed prosthodontics.

Shock Wave Effect on Micromechanics Properties of Sn-Ag-Cu solder (SAC 387) via Nanoindentation

A variety of Sn-Ag-Cu solder alloys have been proposed and recommended for use in industrial organizations for example Sn-95.5Ag3.8Cu-0.7 (SAC 387) by the European Consortium Brite-Euram in the European Union. In this study an effect of shock wave on micromechanics properties of SAC 387 solder was investigated via nanoindentation approach. Solder joint of SAC 387 on copper substrate was prepared by hand soldering techniques. Then soldered samples were exposed to shock wave at different distance of 1 m, 2 m and 3 m. The shock wave test was conducted using 500 g of trinitrotoluene (TNT). Hardness value of SAC 387 decreased from 300 MPa to 130 MPa as well as reduced modulus drop from 115 GPa to 43 GPa after exposure. However the hardness and reduced modulus increased with increasing distance of the shock wave. The phenomenon revealed that shock wave deteriorated the micromechanics properties of soldered samples.

A modified dissipated energy fatigue criterion to consider the thermo-oxidative ageing of electrically conductive silicone adhesive joints

The increasing use of adhesive joints as an assembly technique in various technical fields at the expense of the classical soldering and welding technique brings up the critical questions of their reliability and their lifetime prediction. Fatigue testing of adhesive joints has therefore gained importance in the last few decades, in order to validate the choice of adhesives in structural applications. The influence of environment and ageing on the fatigue life has also gained attention as adhesives are used in wet, or oxidative, or high temperature atmospheres. This paper presents an experimental fatigue study led on a commercial conductive silicone adhesive following the classical stress-life approach. The bonded assemblies were fatigue tested either at virgin state or after thermo-oxidative ageing. Based on results of the fatigue tests, a law relying on two mechanical predictors including the dissipated energy is proposed that considers the influence of a thermo-oxidative ageing of the adhesive joint.

Development of Superconducting Soldered Joints Between Bi-2212/Ag Wires

Bi-2212/Ag superconducting wires are being considered as key conductor candidates for the development of high-field magnets (up to 25 T), but it is recognized that a reliable joining process between these wires is a critical challenge for most high-field applications. This work focuses on the design and testing of jointing processes between multifilamentary Bi-2212 wires to make persistent mode joints using soldering techniques. The ability of several different superconducting solder alloys from the PbBi and SnInBi systems to remove and replace the Ag matrix in fully reacted Bi-2212 wires has been explored. The SnInBi lead-free solder was found to be relatively effective at removing the Ag matrix, but does not make good contact with the Bi-2212 filaments. PbBi solder wets the Bi-2212 filaments more effectively, but is slower at removing the Ag matrix. Therefore, a two-stage process has been developed using molten Sn to first remove the Ag matrix followed by PbBi to replace the nonsuperconducting Sn. Joints made using this two-stage process have higher critical currents (133 A in self-field at 4 K) than joints made using PbBi alone (120 A in self-field at 4 K).

STUDI EKSPERIMEN FINISHING PERHIASAN KUNINGAN DENGAN PERPADUAN ELEKTROPLATING DAN PATINASI

Finishing Research The combination of Patina and electroplating has been carried out according to the research target, which has been able to identify metal materials, especially brass and copper. Bronze and copper Patenting techniques with various jewelry forms. The form of jewelry created amongst other things: bracelets, pendants, jewelry earrings are made with solder technique, tatah, and saws. Before the author experiment and apply patina and electroplating as the main finishing on jewelry on the work of creation. The author first conducted patina and electroplating tests to brass and copper plates with size 2 x 3 cm. The process and results of this research experiment is the answer and the first step which has successfully conducted various scientific experiments with found patina finishing formula with the ideal chemical mixing composition. Research on patina and electroplating experiments can be a contribution to the progress of finishing. Patina finishing research is preferred in brass and copper.Finishing is the finishing touch of a product with a better purpose, such as increasing the quality of the ingredients, increasing the decorative value, increasing the aesthetic value of a product, following the latest design trends, and can increase the selling value of a product. This research is a new research that has not been there before with the method of merging patina and electroplating techniques will be a trend finishing and as a pioneer finishing on jewelry with brass and copper. Keywords: jewelry finishing experiment, patination finishing, finishing electroplating

Study on the estimation of the LED‐package life using a statistical approach

AbstractSince the LED has been popularly used in the lighting field, many of the standards for LED lights such as those regarding LED modules, LED luminaries, and LED lamps have been renewed or newly published. In the development of the relevant standards, many other standards for LED appurtenances have also been developed to measure the LED packages and to produce the luminous flux, color chromaticity, color rendering index, and luminous‐intensity distribution. Although many standards has been developed for different purposes, a standard for the projection of the lumen maintenance of the LED packages and luminaires is nonexistent. LED products are widely known for their long lifetimes, but the formation of accurate definitions of their life periods and the lumen maintenance regarding the LED products are not possible due to the LED‐package components such as the phosper material and the soldering techniques. The method in the IES LM‐80‐08 had been mainly used as an alternative for the projection of the lumen maintenance, but an active discussion of the Border Function and Temperature Acceleration methods in terms of their use as current international standards has occurred. In this study, a new equation for the lumen‐maintenance projection is proposed for the accurate measurement of the lumen maintenance for which a set of 12 LED packages is used. By using the equation, the real value of the LED‐product life can be easily estimated, and it can be compared with the manufacturer claim regarding the value of the LED‐product life.

Joining of thermoelectric material with metallic electrode using Spark Plasma Sintering (SPS) technique

One of the most important challenges faced while producing elements of a thermoelectric module (TEM) is the development of an appropriate joining technology affecting the performance of the whole thermoelectric generator. The produced joints must be characterized not only by high electrical conductivity, high heat conductivity and good adhesion, but also proper mechanical strength and, due to the working conditions, good chemical and temperature stability.This work presents lead-free junctions between a skutterudite material (CoSb3) and a metallic electrode for middle-temperature range applications. The production process and the properties of the obtained junctions are described. The materials were joined by the resistance soldering technique using the Spark Plasma Sintering (SPS) apparatus. The properties of the samples, including their electrical conductivity and Seebeck coefficient were determined and presented. Scanning electron microscopy (SEM) was used to investigate the microstructure, whereas electron dispersive spectroscopy (EDS) was employed to analyze the distribution of the elements. The research was aimed at examining the progress of diffusion between the bounded surfaces. The obtained junction was characterized by a very low resistivity. This work summarizes the properties of the produced junctions and the possibility of their application.

Solderjet bumping packaging technique optimization for the miniaturization of laser devices

BackgroundLow-stress soldering techniques can guarantee a minimized input of thermal energy allowing for the design and later assembly of more robust and miniaturized optical devices. However, in order to build miniaturized optical devices, these small-induced stresses produced by soldering techniques have to be investigated to guarantee that the stress-induced birefringence effects do not alter the device optical properties and requirements.MethodsAn analytical method that relates the stress-induced birefringence of laser components with their corresponding lasing capabilities has been compared to the real induced-stress results created in components packaged using solderjet technology. The main goal was to optimize the optical component packaging by using this low induced-stress soldering technique. The optimization was carried out by assessing components miniaturization while still assuring high robustness of the bond strength without creating a beam depolarization ratio of more than 1%.ResultsThe outcome of the study showed the possibility of assembling laser optical components down to sizes of around 300 μm, creating a bond strength of 5 N and higher, and a depolarization ratio much lower than the proposed target of 1%.ConclusionsOur results in terms of induced stress agreed with the finite element method result, which would imply correct post-processing laser simulations. This suggested that the solderjet bumping technique could robustly join components down to the laser emission beam size without strongly affecting the optical properties.

Universal Soldering of Lithium and Sodium Alloys on Various Substrates for Batteries

AbstractThe high theoretical specific capacity of lithium (Li) metal and the nonflammability of solid‐state electrolytes (SSEs) make the solid‐state Li metal battery a promising option to develop safe batteries with high energy density. To make the switch from liquid to solid‐state electrolyte, the high interfacial resistance resulting from the poor solid–solid contacts between Li metal and SSEs needs to be addressed. Herein, a one‐step soldering technique to quickly coat molten Li onto different substrates including metals, ceramics, and polymers is presented. It is deduced that the surface energy and viscosity of the molten Li can be tuned by adding alloy elements, which improves the wettability against various substrates. When soldered onto the surface of garnet‐based SSEs, the Li alloys exhibit significantly improved contact, which leads to an interface resistance as low as ≈7 Ω cm2. While cycling under high loads, the newly plated Li still maintains tight contact with the garnet surface and demonstrates excellent electrochemical stability. Several Li binary alloys as well as sodium (Na) binary alloys are successfully tested on various substrates to demonstrate the versatility of this soldering technique for potential battery applications.

Strength and reliability of low temperature transient liquid phase bonded Cu[sbnd]Sn[sbnd]Cu interconnects

As power electronic devices have tendencies to operate at higher temperatures and current densities, the demand for reliable and efficient packaging technologies are ever increasing. This paper reports the studies on application of transient liquid phase (TLP) bonding of CuSnCu systems as a potential technology that could enable the realization of stacks with better thermal performance and reliability than those can be achieved using conventional soldering techniques. Low temperature TLP bonded CuSnCu samples are fabricated, and the strength of the achieved bonds is measured by shear testing. Micro-sectioning and optical microscopy studies of the samples reveal that the TLP bonds show good homogeneity with a small number of voids at the interface. Energy dispersive X-ray analysis is applied to examine at what rates Sn is converted into CuSn intermetallics since a full conversion is critical for achieving a strong and high temperature resistant bond. Finally, initial results from a thermal cycling test are presented and it is concluded that the achieved TLP bonding is a promising candidate for the fabrication of reliable interconnects in power electronics.

Method to simulate and analyse induced stresses for laser crystal packaging technologies.

A method to simulate induced stresses for a laser crystal packaging technique and the consequent study of birefringent effects inside the laser cavities has been developed. The method has been implemented by thermo-mechanical simulations implemented with ANSYS 17.0. ANSYS results were later imported in VirtualLab Fusion software where input/output beams in terms of wavelengths and polarization were analysed. The study has been built in the context of a low-stress soldering technique implemented for glass or crystal optics packaging's called the solderjet bumping technique. The outcome of the analysis showed almost no difference between the input and output laser beams for the laser cavity constructed with an yttrium aluminum garnet active laser crystal, a second harmonic generator beta-barium borate, and the output laser mirror made of fused silica assembled by the low-stress solderjet bumping technique.

High cycle fatigue testing of thermosonic ball bonds

During operation, miniaturized thermosonic Cu ball bond interconnects on Al pads occurring in microelectronic devices experience thermomechanical cyclic stresses, which lead to a degradation and subsequent fatigue fracture at the bond interface. Standard static tests, however, ignore the performance of such bonds under cyclic loads.Therefore, a new mechanical fatigue testing method tailored for such interconnects has been introduced, allowing to study their high cycle fatigue behavior in reasonable time. By means of a vibrating system and a special specimen setup cyclic stresses are mechanically induced at the bond interface causing fatigue lift off, where the bond is separated at its weakest site.For this purpose, two distinct specimen preparation methods basing on industrially applicable soldering techniques are suggested and can be used equally, depending on the focus of the investigation and the availability of the required testing structures.The first method - “single bond testing” - allows to test each bond individually regardless of the chip layout. In contrast, the second test method - “multiple bond testing” - allows to test several bonds simultaneously. To interpret and analyze the stresses occurring at the bond interface during these tests, finite element analyses were conducted.In the present study both methods are applied to CuAl ball bonds of the same quality and chip layout. It is shown that the aluminum is responsible for the fatigue crack initiation and propagation processes as confirmed by fractographic analyses of the fatigued bond interfaces.It can be concluded that the proposed fatigue test method is a powerful alternative screening method for such miniaturized bond interfaces, which allows to reveal their mechanical fatigue behavior in reasonable time and to identify the weakest link of the tested bond interface.

Evolution of microstructure and mechanical properties of Cu/SAC305/Cu solder joints under the influence of low ultrasonic power

Abstract Cu/SAC305/Cu solder joints were fabricated by a modified ultrasonic-assisted reflow soldering technique under ambient atmosphere. Ultrasonic vibration (USV) with low ultrasonic power ranging from 10 to 30 W was used while the evolution of microstructure and mechanical properties of the solder joints under the influence of such USV were investigated in this study. Results showed that ultrasonic power promoted the formation of eutectic phase and the coarsening of β-Sn phase in the solder matrix of the solder joints. When the samples were treated with longer USV time, the β-Sn phase changed from dendritic structure (10 W of USV) to globular structure (20 and 30 W of USV). The observed morphological change of β-Sn and eutectic phases in the solder matrix led to the variation in the solder matrix hardness and the formation of interfacial intermetallic compounds (IMCs) in the samples treated with USV at increasing ultrasonic power and time. Overall, the shear strength of the ultrasonic-treated samples increased with increasing ultrasonic power, regardless of the USV time.

Bottom-up nanoarchitectures of semiconductor nano-building blocks obtained via a controllable in situ SEM-FIB thermal soldering method

Nanoscale semiconductor building blocks can be controllably soldered together via a novel in situ SEM-FIB thermal soldering technique.

Assembly processes comparison for a miniaturized laser used for the Exomars European Space Agency mission

A miniaturized diode-pumped solid-state laser (DPSSL) designed as part of the Raman laser spectrometer (RLS) instrument for the European Space Agency (ESA) Exomars mission 2020 is assembled and tested for the mission purpose and requirements. Two different processes were tried for the laser assembling: one based on adhesives, following traditional laser manufacturing processes; another based on a low-stress and organic-free soldering technique called solderjet bumping technology. The manufactured devices were tested for the processes validation by passing mechanical, thermal cycles, radiation, and optical functional tests. The comparison analysis showed a device improvement in terms of reliability of the optical performances from the soldered to the assembled by adhesive-based means.

High-precision optomechanical lens system for space applications assembled by a local soldering technique

Soldering using metallic solder alloys is an alternative to adhesive bonding. Laser-based soldering processes are especially well suited for the joining of optical components made of fragile and brittle materials such as glass, ceramics, and optical crystals. This is due to a localized and minimized input of thermal energy. Solderjet bumping technology has been used to assemble a lens mount breadboard using specifications and requirements found for the optical beam expander for the European Space Agency EarthCare Mission. The silica lens and a titanium barrel have been designed and assembled with this technology in order to withstand the stringent mission demands of handling high mechanical and thermal loads without losing the optical performance. Finally, a high-precision optomechanical lens mount has been assembled with minimal localized stress (<1 MPa) showing outstanding performance in terms of wave-front error and beam depolarization ratio before and after environmental tests.

마이크로솔더링을 이용한 정전류다이오드 회로 자외선 LED 광원모듈 제작

The improvement of irradiation intensity and irradiation uniformity is essential for large area and high power UVA light source application. In this study, large number of chips bonded by micro soldering technique were driven by low current, and current limiting diodes were configured to supply constant current to parallel circuits consisting of large number of series strings. The dimension of light source module circuit board was 350 × 90 mm 2 and 16,650 numbers of 385 nm flip chip LEDs were used with a configuration of 90 parallel and 185 series strings. The space between LEDs in parallel and series strings were maintained at 1.9 mm and 1.0 mm distance, respectively. The size of the flip chip was 750 × 750 µm 2 were used with contact pads of 260 × 669 µm 2 size, and SAC (96.5 Sn/3.0 Ag/0.5 Cu) solder was used for flip chip bonding. The fabricated light source module with 7.5 m A supply current showed temperature rise of 66℃, whereas irradiation was measured to be 300 mW/cm 2 . Inaddition, 0.23% variation of the constant current in each series string was demonstrated.

Early Medieval silver pearl from Lumbe's garden cemetery at Prague Castle: Composition, manufacture, deterioration, and conservation

As part of our grant-funded research into the metallic artefacts excavated in Lumbe's garden cemetery at Prague Castle (a site where the members of the nobility were buried during the early Medieval period), a silver pearl (grave 100, object 27) dating from the ninth century and found in a grave of one of the wealthiest individuals was investigated. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, metallographic examination, and the manufacture of a replica enabled us to identify the process of the pearl's manufacture, the material which was used for its fabrication, and the extent of the pearl's deterioration. The pearl is a masterpiece of filigree and granulation work. Analyses have shown the nature of the soldering technique and the types of materials used by early Medieval craftsmen to manufacture it. The analyses also highlighted the nature of the pearl's deterioration, involving intergranular corrosion resulting in the embrittlement of the silver, as well as indications of an aggressive restoration treatment which had been performed on the pearl.