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Traditional methods for closing gastrointestinal (GI) surgery incisions, like suturing and stapling, present significant challenges, including potentially life-threatening leaks. These techniques, especially in robot-assisted minimally invasive surgery (RAMIS), require advanced manual skills. While their repetitive and time-consuming nature makes them suitable candidates for automation, the automation process is complicated by the need for extensive contact with the tissue. Addressing this, we demonstrate a semi-autonomous contactless surgical procedure using our novel Robot-assisted Laser Tissue Soldering (RLTS) system on a live porcine bowel. Towards this in-vivo demonstration, we optimized soldering protocols and system parameters in ex-vivo experiments on porcine bowels and a porcine cadaver. To assess the RLTS system performance, we compared the pressure at which the anastomosis leaked between our robotic soldering and manual suturing. With the best setup, we advanced to an in-vivo Heineke Mikulicz closure on small bowel incision in live pigs and evaluated their healing for two weeks. The five pigs that successfully completed the procedure, survived without leaks and histology indicated mucosal regeneration and fibrous tissue adhesion. This marks the first in-vivo semi-automated contactless incision closure, paving the way for automating GI surgery incision closure which has the potential to become an alternative to traditional methods.

PurposeIn the production processes of electronic devices, production activities are interrupted due to the problems caused by soldering defects during the assembly of surface-mounted elements on printed circuit boards (PCBs), and this leads to an increase in production costs. In solder paste applications, defects that may occur in electronic cards are usually noticed at the last stage of the production process. This situation reduces the efficiency of production and causes delays in the delivery schedule of critical systems. This study aims to overcome these problems, optimization based deep learning model has been proposed by using 2D signal processing methods.Design/methodology/approachAn optimization-based deep learning model is proposed by using image-processing techniques to detect solder paste defects on PCBs with high performance at an early stage. Convolutional neural network, one of the deep learning methods, is trained using the data set obtained for this study, and pad regions on PCB are classified.FindingsA total of six types of classes used in the study consist of uncorrectable soldering, missing soldering, excess soldering, short circuit, undefined object and correct soldering, which are frequently used in the literature. The validity of the model has been tested on the data set consisting of 648 test data.Originality/valueThe effect of image processing and optimization methods on model performance is examined. With the help of the proposed model, defective solder paste areas on PCBs are detected, and these regions are visualized by taking them into a frame.

Fluxes have a negative impact on the environment; as a result, fluxless soldering has become a promising method in electronic packaging. However, detailed studies on fluxless soldering are very rare, especially those involving the use of electroless nickel immersion gold (ENIG) substrate under formic acid (FA) atmosphere that can effectively reduce the majority of solders. In this work, the characteristic parameters of FA reflow soldering performed by combining Sn–3.5Ag–0.5Cu (SAC305) solder and ENIG substrate are compared with the soldering conducted using liquid rosin mildly activated (RMA) flux. It is found that the wettability of FA-exposed solder is greater than that of RMA-containing solder because the former spreads across the interfacial layer of intermetallic compounds (IMCs) produced before the melting of SAC305. Additionally, the interfacial reactions of FA-exposed solder resemble those of RMA solder before and after the thermal aging at 150 °C. Therefore, the impact strengths of these two solders are almost the same due to the similarity of their microstructures and close growth rates of (Cu,Ni)6Sn5 IMC layers during thermal aging. The findings of this study suggest that FA reflow soldering is a promising environmentally friendly technique for electronic packaging.

This paper aims to develop a thermal fluid–structure interaction (FSI) methodology to study the effect of different Cu pillar bump diameters on thermal and mechanical performance during the reflow soldering process. The desktop reflow oven is modeled in ANSYS FLUENT, while the ball grid array (BGA) package assembly is modeled in ANSYS STATIC STRUCTURAL. The accuracy of the simulated reflow temperature profile has been verified by comparing it with the experimental temperature data, according to JEDEC standards. The temperature distributions of solder and Cu pillar bumps are compared. A parametric study has been conducted to analyze the effect of different Cu pillar diameters on the reflow soldering process. By coupling the thermal loads with the structural analysis using thermal FSI, Cu pillar bumps with a diameter of 0.20 mm are found to exhibit the lowest reflow temperature, minimum temperature difference, and minimum deformation and thermal stress, making them the most suitable interconnection joints for flip chip technology. The study also examines the effect of soldering materials on the Cu pillar bump. The findings of this research provide valuable insights into the effects of varying Cu pillar diameters on the reflow soldering process, which can help in the development of more reliable electronic assemblies.

The main purpose of the software application is to simulate the temperature field in the process of induction pack of elements of machine-building structures of the fuel profile, which will further improve the quality of connections. The program simulates the flange heating process during the induction brazing process. The purpose of the developed module is to provide experimental studies of the induction soldering process. The program provides graphic information during the technological process, provides the ability to adjust the technological parameters, and allows the development of the technological process.

This paper investigates the effect of soldering temperature on solder joint voids and reliability of flip-chip LED chips during reflow soldering. Lead-free solder SAC305 was used as solder paste. The void ratio of the flip-chip LED solder joint at 250°C, 260°C, 270°C, 280°C, and 290°C reflow soldering temperatures was detected by x-ray detector. Shear tests were conducted to evaluate the influence of interfacial reactions on the mechanical reliability of solder joints. The distribution of voids in the shear section was observed by scanning electron microscope (SEM). Next, the photoelectric and thermal properties of FC-LED filament were tested and analyzed. Finally, a high-temperature and high-humidity aging experiment was carried out to test the reliability of the LED filament. The results show that the void ratio of the LED filament soldering joint is the lowest when the soldering temperature is 270°C. The small void ratio of the solder joints results in lower steady-state voltage and junction temperature of the flip-chip LED filament. As the void density in the solder joint decreases, the shear strength of the solder joint increases. At this time, the shear resistance and mechanical reliability are the highest.

In this paper, the factors affecting the reliability of small-size PBGA with low thermal expansion coefficient are determined by theoretical and simulation analysis. The simulation results are verified by reliability test, dye penetration, metallographic section, and electron microscope scanning analysis, revealing that the height and diameter of solder joints are reliable with low CTE small size PBGA. The high-reliability welding process method of this kind of device is obtained, which is of great significance for the quality assurance of aviation and aerospace electronic products.

With the continuous downsizing of solder joints, the influence of the grain characteristics of the under bump metallization (UBMs) on the interfacial reaction is exposed. In this paper, the effect of grain characteristics of Cu UBM on the growth of interfacial intermetallic compounds and the formation of Kirkendall voids in Cu/Sn/Cu micro solder joints during isothermal aging at 150 °C was investigated. Electroplated polycrystalline Cu (EP-Cu), (111) single crystal Cu ((111) Cu), and (111) nano-twinned Cu ((111) nt-Cu) were selected as UBMs. After reflow soldering, the Cu 6 Sn 5 grains formed on (111) nt-Cu were near to the orientation (2 1 - 1 - 3) , while those were randomly formed on both EP-Cu and (111) Cu. During isothermal aging, the Cu 6 Sn 5 grains exhibited the highest growth rate on (111) nt-Cu UBM, and the slowest growth rate on (111) Cu UBM, due to the differing number of diffusion routes among the three Cu UBMs with distinct grain characteristics. Furthermore, no Kirkendall voids were detected on the (111) Cu UBM, however, a significant number of Kirkendall voids were identified on the (111) nt-Cu UBM, which can be attributed to the diffusion path and impurities present in the three Cu UBMs. The results will offer theoretical and practical recommendations for the selection of Cu UBMs for micro solder joints in 3D packaging interconnection technology.

Advances in membrane technologies are significant for mitigating global climate change because of their low cost and easy operation. Although mixed-matrix membranes (MMMs) obtained via the combination of metal-organic frameworks (MOFs) and a polymer matrix are promising for energy-efficient gas separation, the achievement of a desirable match between polymers and MOFs for the development of advanced MMMs is challenging, especially when emerging highly permeable materials such as polymers of intrinsic microporosity (PIMs) are deployed. Here, we report a molecular soldering strategy featuring multifunctional polyphenols in tailored polymer chains, well-designed hollow MOF structures, and defect-free interfaces. The exceptional adhesion nature of polyphenols results in dense packing and visible stiffness of PIM-1 chains with strengthened selectivity. The architecture of the hollow MOFs leads to free mass transfer and substantially improves permeability. These structural advantages act synergistically to break the permeability-selectivity trade-off limit in MMMs and surpass the conventional upper bound. This polyphenol molecular soldering method has been validated for various polymers, providing a universal pathway to prepare advanced MMMs with desirable performance for diverse applications beyond carbon capture. The development of mixed-matrix membranes is especially challenging when highly permeable materials are used. Here the authors present a molecular soldering strategy featuring multifunctional polyphenols in tailored polymer chains, well-designed hollow MOF structures, and defect-free interfaces to break the permeability-selectivity trade-off limit.

This study investigates the potential application of Zn5Al1.5Mg1.5Ti active solder in ultrasonic soldering of Al2O3 ceramics and Cu substrates. The research explores the microstructural characteristics, phase composition, and mechanical properties of the solder and the resulting joints. Particular attention is given to the formation mechanisms of the solder–substrate bond and the role of ultrasound activation in enhancing wettability and bond strength. The study aimed to provide a deeper understanding of active soldering processes and their suitability for high-temperature applications. The findings contribute to advancing lead-free soldering technologies for electronic and structural applications.