Assembly Reliability Research Articles

Sustainable Silk Fibroin Ionic Touch Screens for Flexible Biodegradable Electronics with Integrated AI and IoT Functionality.

The increasing prevalence of electronic devices has led to a significant rise in electronic waste (e-waste), necessitating the development of sustainable materials for flexible electronics. In this study, silk fibroin ionic touch screen (SFITS) is introduced, a new platform integrating natural silk fibroin (SF) with ionic conductors to create highly elastic, environmentally stable, and multifunctional touch interfaces. Through a humidity-induced crystallization strategy, the molecular structure of SF is precisely controlled to achieve a balanced combination of mechanical strength, electrical conductivity, and biodegradability. The assembly and operational reliability of SFITS are demonstrated under various environmental conditions, along with their reusability through green recycling methods. Additionally, the intelligent design and application of SFITS are explored by incorporating Internet of Things (IoT) and artificial intelligence (AI) technologies. This integration enables real-time touch sensing, handwriting recognition, and advanced human-computer interactions. The versatility of SFITS is further exemplified through applications in remote control systems, molecular model generation, and virtual reality interfaces. The findings highlight the potential of sustainable ionic conductors in next-generation flexible electronics, offering a path toward greener and more intelligent device designs.

Large mitochondrial genomes in tenthredinid sawflies (Hymenoptera, Tenthredinidae)

We sequenced and assembled mitochondrial genomes of three tenthredinid sawflies (Euura poecilonota, E. striata, and Dolerus timidus) using Oxford Nanopore Technologies’ MinION. The Canu assembler produced circular assemblies (23,000–40,000 bp). Still, errors were found in the highly repetitive non-coding control region because of the fragmented DNA which led to no reads spanning the complete control region, preventing its reliable assembly. Based on the non-repetitive coding region’s sequencing coverage, we estimate the lengths of mitochondrial genomes of E. poecilonota, D. timidus, and E. striata to be about 30,000 bp, 31,000 bp, and 37,000 bp and control region to be 15,000 bp, 16,000 bp, and 22,000 bp respectively. All standard bilaterian mitochondrial genes are in the same order and orientation, except trnQ, which is on the minus strand in Euura and the plus strand in Dolerus. Using published tenthredinid genome data, we show that control region lengths are often underestimated.

Robot skill acquisition for precision assembly of flexible flat cable with force control

Abstract The flexible flat cable (FFC) assembly task is a prime challenge in electronic manufacturing. Its characteristics of being prone to deformation under external force, tiny assembly tolerance, and fragility impede the application of robotic assembly in this field. To achieve reliable and stable robotic automation assembly of FFC, an efficient assembly skill acquisition strategy is presented by combining a parallel robot skill learning algorithm with adaptive impedance control. The parallel robot skill learning algorithm is proposed to enhance the efficiency of FFC assembly skill acquisition, which reduces the risk of damaging FFC and tackles the uncertain influence resulting from deformation during the assembly process. Moreover, FFC assembly is also a complex contact-rich manipulation task. An adaptive impedance controller is designed to implement force tracking during the assembly process without precise environment information, and the stability is also analyzed based on the Lyapunov function. Experiments of FFC assembly are conducted to illustrate the efficiency of the proposed method. The experimental results demonstrate that the proposed method is robust and efficient.

Design and vibration test of first mirror mount assembly for ITER divertor VUV spectrometer

The divertor vacuum ultraviolet (VUV) spectrometer is a diagnostic system in the ITER tokamak, monitoring impurity content and behavior in the divertor region. The first mirror of the spectrometer, made of silicon carbide (SiC), is exposed to harsh environmental conditions, including high temperatures and significant inertial loads from electromagnetic disruption events. To ensure its reliable performance, we have designed and tested a robust mirror holder assembly. This paper introduces a novel design of the first mirror holder assembly for the ITER divertor VUV spectrometer and presents the results from comprehensive vibration tests conducted on a full-scale mock-up. The design features a double-holder structure with spring plate assemblies to accommodate thermal expansion and resist vibrational loads. The mock-up underwent a series of resonance search, sine dwell, and random vibration tests, replicating the expected loads during vertical displacement events in ITER. The mirror holder assembly and the dummy mirror successfully withstood the vibration tests without damage, validating the design for the ITER environment. The results demonstrate the robustness and reliability of the mirror holder assembly, ensuring the accurate and reliable operation of the divertor VUV spectrometer in ITER.

АНАЛІЗ ВПЛИВУ ІНДИВІДУАЛЬНИХ ХАРАКТЕРИСТИК КОМІРОК LiFePO4 НА ПАРАМЕТРИ РОБОТИ АКУМУЛЯТОРНИХ ЗБІРОК

The article analyzes the influence of the individual characteristics of lithium-iron-phosphate (LiFePO4) cells on the overall efficiency, stability and duration of operation of battery assemblies. The influence of such parameters as internal resistance, polarization resistance and capacity on the operation of battery assemblies under different load regimes and changes in temperature conditions was studied. It was found that these parameters can vary significantly between cells within the same assembly, which leads to an imbalance during the operation of the battery system. Such an imbalance causes an uneven distribution of charge between the cells, which reduces the overall performance of the system, accelerates the degradation of the cells and shortens their service life. To overcome these problems, the use of active balancing methods based on Unscented Kalman Filter (UKF) algorithms was proposed. The application of UKF allows for dynamic evaluation of the state of charge (SOC) of each cell and adjustment of system parameters in real time, which provides more accurate management of battery assemblies in conditions of variable external factors such as temperature and current loads. Special attention is paid to online identification of battery parameters, such as polarization resistance and capacity, which change over time due to cell aging. The conducted studies confirmed that constant monitoring of temperature regimes is critically important for maintaining stable operation of battery cells, preventing overheating and ensuring uniform load distribution. The performed simulation confirmed the effectiveness of the application of adaptive methods of balancing and temperature control, which allows to increase the reliability and overall performance of battery assemblies.

The Influence of the Assembly Line Configuration and Reliability Parameter Symmetry on the Key Performance Indicators

In the context of the demand for mass customization of products, a trade-off between highly efficient automated systems and flexible manual operators is sought. The linear arrangement of workstations made it possible to divide the process into many simple operations, which increases production efficiency, but also results in an increase in the number of workstations and a significant extension of the line. A human operator is usually treated as a quasi-mechanical object, and a human error is considered, similarly, as a failure of a technical component. However, human behavior is more complex and difficult to predict. A mathematical model of a new production organization is presented, including dividing the traditional production line into shorter sections or replacing the serial assembly line with a U-line with cells. Moreover, the reliability of operator and technical means are distinguished. Work-in-progress inventories are located between line sections to improve system stability. The stability of the assembly line is examined based on the system configuration and probabilistic estimates of human failure. The influence of the symmetry of reliability parameters of people on key performance indicators (KPI (headcount), KPI (surface) and KPI (Overall Equipment Effectiveness) is examined. KPI (solution robustness) and KPI (quality robustness) are also presented in order to evaluate the impact of a disruption on the assembly line performance. New rules for assigning tasks to stations are proposed, taking into account the risk of disruptions in the execution of tasks. For comparison of assembly problems, heuristic methods with newly developed criteria are used. The results show the impact of symmetry/asymmetry on assembly line performance and an asymmetric distribution of manual assembly times that is significantly skewed to the right due to human errors. On the assembly line, the effects of these errors are cumulative and lead to longer assembly times and lower KPIs.

Damage Mechanism Analysis of the Connecting Screw of Turbine Disk-Drum Assembly

The turbine disk-drum is one of the key components of an aero-engine and its assembly is connected with high-strength refined screws. But due to the uncoordinated rotation and deformation, the screws have abnormal wear damage. Through detailed contact stress analysis of screw body and component level using the finite element method, combined with experimental observation, the mechanism of wear damage of screw surface in screws is determined. It mainly includes the following: Firstly, the finite element method is used to calculate the deformation and stress distribution of the connecting screw of the turbine disk-drum assembly. Then, after the overspeed test, the morphology of the screws disassembled from the disk-drum assembly is evaluated. It was found that the wear degree in the circumferential direction and axial direction of the screw was quite different, that is, the screw wear experiment was consistent with the finite element analysis results. Finally, the influence of different rotation states and screw tightening states on screw wear was compared and analyzed. Conclusions obtained in this paper will be helpful to improve the assembly reliability of turbine drum.

Revealing patterns of change in the tribological efficiency of composite materials for machine parts based on phenylone and polyamide reinforced with arimide-t and fullerene

The object of the study is the process of changing tribological efficiency according to tribotechnical characteristics (wear intensity, friction coefficient, temperature in the contact zone) of composites based on phenylone C-1 and polyamide PA-6 with arimide-T filler and fullerene C-60. The study solved the problem of obtaining composites with high wear resistance. Based on the results of research, it was found that varying the content of arimide-T makes it possible to obtain composites with different patterns of changes in tribotechnical characteristics under conditions of dry friction, lubrication with water and I-50 oil. Composites with the composition: phenylone C-1+15 wt. have the maximum tribological efficiency. % arimide-T+3 wt. % fullerene C-60 and polyamide PA-6+30 wt. % arimide-T+3 wt. % fullerene C-60. Phenylone C-1 has destructive properties when working in the environment of water and temperature in the friction zone. Its reinforcement with arimide-T and fullerene C60 gave positive results of a complex of tribotechnical characteristics under these conditions. It was found that the wear of composites based on phenylone C-1 in I-50 oil is two orders of magnitude lower than in water. Research of samples from the obtained composites based on phenylone C-1 and polyamide PA-6, reinforced with the optimal content of arimide-T and fullerene C60, showed that their wear resistance when lubricated with oil is 3.5...4.0 times greater than the wear resistance of bronze. An applied aspect of the reported results is the introduction of manufacturing technologies and restoration of machine parts from the proposed composites. It has been proven that their optimal composition contributes to high tribological efficiency and could provide the required level of wear resistance and reliability of resource-determining nodes, systems, and machine assemblies. The results could be used by machine-building and repair-technological enterprises

Computational and experimental substantiation of the operability of seals of localizing safety system elements of power units with VVER

The relevance of this work is determined by the need to predict the operation of sealing assemblies for elements of localizing safety systems (LSSs) of power units with VVER, which include (penetrations, hatches, locks, doors and other elements of hermetic fencing (GF) in operational modes. Operational modes are understood as modes of normal operation, modes of violation of normal operation, as well as emergency situations. During the manufacture and operation of LSS elements, the problem arises of uneven protrusion of a double-row rubber seal from the grooves in the web of the LSS element, which leads to the need to clarify the integral compression force of the seal as a whole for this element. The problem is caused by the imperfection of the manufacturing technology of large canvases for LSS elements (doors, hatches, locks: the perimeter of the seals can reach 10-20 m, the diameter of the canvas 2-6 m) and the need to withstand stringent technological requirements for flatness, parallelism and marginal deviations in linear and angular dimensions. The manufacture of overall structures is complicated by the presence of welded joints, heat treatment, and the complexity of metalworking. Compression force of the PNAE rubber gasket-7-002-86 it is not regulated, therefore, for the reliable design of gasket compression mechanisms, the magnitude of this force was determined. Based on the obtained results of tests of rubber seals for tightness and cyclic loading [7], an assessment of the tightness of the applied rubber seals is performed, calculations of deformations of rubber seals are performed using the FEM software package. Recommendations have been developed to increase the reliability of seal assemblies for elements of localizing safety systems (LSSs) of VVER power units in operational modes and to select the compression value to determine the necessary force to ensure tightness at the beginning of operation and after 5000 opening-closing cycles.

An Innovative, Cost-Effective, and Flexible Traction Alternative for Shoulder Arthroscopy in Lateral Decubitus Position

During shoulder arthroscopic surgery in the lateral decubitus position, effective and stable continuous traction is a basic requirement for the smooth progression of the surgery. Herein, we describe a safe, reliable, and cost-effective lateral decubitus traction assembly.

A novel fuzzy algorithm for assembly precision management

The assembly precision of a specified product is subject to epistemic uncertainty due to manufacturing and measurement errors. The efficient and accurate assembly precision management is essential for realizing smart production lines, which rely on the robust assembly precision analysis model and calculation method. Parametric models are extensively used for assembly precision analysis in industrial products, typically integrating worst-case and statistical methods for calculations. Nevertheless, the combined application of these methods presents inherent limitations. Therefore, a novel fuzzy algorithm for assembly precision management is proposed in this paper by using fuzzy sets to quantify epistemic uncertainty in assembly precision, which integrates the proposed fuzzy-based assembly precision analysis model and fuzzy-based calculation method. The proposed fuzzy small displacement torsor model is a fuzzy-based model for deviation representation and tolerance classification using decomposed fuzzy numbers, where an assembly reliability index is always established for the hierarchical evaluation and management of assembly precision. Subsequently, a comprehensive assembly precision analysis model is developed for precision prediction and contribution quantification by integrating the Jacobian model for deviation propagation. A new constrained transformation method is proposed as a fuzzy-based calculation method, offering efficient and highly accurate assembly precision computation. It accounts for torsor parameter constraints to ensure greater prediction accuracy than the worst-case method and improves computational efficiency compared to statistical methods. An assembly case of the centering pin mechanism is applied to verify the superiority of the proposed novel fuzzy algorithm compared with the Jacobian-Torsor model with worst-case or statistical methods.

92‐5: Late‐News Paper: Development of a Full‐Color MicroLED Display Utilizing Novel Simultaneous Transfer and Bonding (SITRAB) Process and SITRAB Film Technology

In this study, we introduce the world's first development of a full‐color micro‐LED display utilizing a Simultaneous Transfer and Bonding (SITRAB) process and a novel SITRAB film. Developed micro‐LED display involves R/G/B micro‐LED chips measuring 35 × 20 µm 2, arranged into a display resolution of 32 × 32, with a pixel pitch of 324 µm and a subpixel pitch of 50 µm. The micro‐LED display utilizes a glass substrate and aluminum wiring. A key innovation in our process is the use of indium solder for low‐temperature bonding, significantly enhancing the assembly process's efficiency and reliability. The SITRAB film, a specially developed material by ourselves, removes the surface oxide of indium solders, facilitating effective bonding between the micro‐LEDs and the display electrodes. Post‐curing of this SITRAB film further enhances the shear strength of the micro‐LEDs. An average shear strength of approximately 5.45 gf (about 32 MPa), significantly surpassing the tensile strength of indium. These advancements not only demonstrate the feasibility of the SITRAB process and the new film material in creating high‐quality micro‐LED displays but also significantly boost the reliability of these displays.

Investigating the impact of different solder alloy materials during laser soldering process

PurposeThis study aims to investigate the influence of different solder alloy materials on passive devices during laser soldering process. Solder alloy material has been found to significantly influence the solder joint’s quality, such as void formation that can lead to cracks, filling time that affects productivity and fillet shape that determines the solder joint’s reliability.Design/methodology/approachFinite volume method (FVM)-based simulation that was validated using real laser soldering experiment is used to evaluate the effect of various solder alloy materials, including SAC305, SAC387, SAC396 and SAC405 in laser soldering. These solders are commonly used to assemble the pin-through hole (PTH) capacitor onto the printed circuit board.FindingsThe simulation results show how the void ratio, filling time and flow characteristics of different solder alloy materials affect the quality of the solder joint. The optimal solder alloy is SAC396 due to its low void ratio of 1.95%, fastest filling time (1.3 s) to fill a 98% PTH barrel and excellent flow characteristics. The results give the ideal setting for the parameters that can increase the effectiveness of the laser soldering process, which include reducing filling time from 2.2 s to less than 1.5 s while maintaining a high-quality solder joint with a void ratio of less than 2%. Industries that emphasize reliable soldering and effective joint formation gain the advantage of minimal occurrence of void formation, quick filling time and exceptional flowability offered by this solution.Practical implicationsThis research is expected not only to improve solder joint reliability but also to drive advancements in laser soldering technology, supporting the development of efficient and reliable microelectronics assembly processes for future electronic devices. The optimized laser soldering material will enable the production of superior passive devices, meeting the growing demands of the electronics market for smaller, high-performance electronic products.Originality/valueThe comparison of different solder alloy materials for PTH capacitor assembly during the laser soldering process has not been reported to date. Additionally, volume of fluid numerical analysis of the quality and reliability of different solder alloy joints has never been conducted on real PTH capacitor assemblies.

Enhancing Structural Vibration Damping in Marine Machinery: A Comprehensive Numerical Investigation with Modal and Harmonic Analysis

This article presents a comprehensive study on the damping of vibrations in a motor-pump assembly using viscoelastic and constrained layer damping treatments. The assembly's structural model, designed using SolidWorks software, is subjected to modal and harmonic analyses in ANSYS. The primary goal is to mitigate vibration amplitudes originating from the motor and pump to enhance the assembly's operational performance. Three damping treatments are investigated: Free Layer Damping (FLD), Sandwich Constrained Layer Damping (CLD), and a novel Multilayer CLD approach. The viscoelastic material is modeled using the Prony series method, and its properties are incorporated into the finite element analysis Results demonstrate that the application of damping treatments significantly reduces vibration amplitudes compared to the untreated structure. Among the treatments, the Multilayer CLD approach exhibits the highest damping efficiency, reducing the maximum amplitude by approximately 52% compared to the base structure. The study showcases the advantages of utilizing viscoelastic and constrained layer damping techniques for enhancing vibration control and operational stability in industrial assemblies. The research findings contribute to the field of structural dynamics and vibration control, offering valuable insights into the design and optimization of mechanical systems subjected to dynamic loads. This study opens avenues for further research and practical applications aimed at improving the performance and reliability of motor-pump assemblies and similar industrial equipment.

Research on the influence of vehicle durability vibration on gap flush of exterior trim parts

Maintaining the newness of a vehicle is currently significant concern for users and vehicle companies. The gap difference between interior and exterior trims plays a crucial role in the overall appearance of vehicles. Over time, the gap and flush parameters of these trims may change due to the movement of components, putting forward higher requirements for the assembly accuracy and reliability design of automotive products. This article presents a study where a test car is subjected to endurance vibration on a wheel-coupled vibration bench. Through measuring the changes in gaps and flushes between the exterior trim parts at different endurance mileage intervals, the variation patterns are obtained. Using dimensional engineering technology, the effects of durable vibration on the gaps and flushes of the vehicle's exterior trim parts were determined. This study provides a foundation for the design of new interior and exterior decoration parts in automobiles. It also offers valuable insights for product design, development, and quality improvement. Problems can be predicted in advance in the early stage of design, and closely coordinate various aspects of production and manufacturing to obtain products with higher standards, requirements, and quality.

ВЛИЯНИЕ НАДЕЖНОСТИ АВТОМОБИЛЕЙ НА ЗАТРАТЫ НА ПРИОБРЕТЕНИЕ ЗАПАСНЫХ ЧАСТЕЙ

The operation of road transport is associated with maintaining the serviceability of vehicles. Companies that operate vehicles have different approaches to ensuring their serviceability. Small ones, as a rule, carry out maintenance and repair of vehicles at service stations, while large and medium-sized companies provide conditions for carrying out technical service at their own base. In this case, they are faced with the need to stock with spare parts. It was found that the costs of spare parts account for up to 45 % of all operating costs, their reduction is possible with the correct approach to planning and organization of spare parts supply. This confirms the relevance of the research. As the main factor affecting the cost of spare parts purchasing, the authors proposed to consider the reliability of car units and assemblies. A regularity was established: the reliability of a vehicle decreases with the increase of its service life, while the need for spare parts and, consequently, the purchasing cost of spare parts increases. Spare parts stocks are planned in two groups – for maintenance and repairs. It is possible to plan the consumption of spare parts for maintenance based on the vehicle fleet and on the recommendations of the manufacturer, which regulates the frequency of replacement and the list of spare parts. It is advisable to plan the nomenclature of spare parts for current repairs based on vehicles reliability. Forecasting of spare parts stock based on reliability will allow to manage spare parts stock effectively, to minimize their shelf life and to avoid the purchase of unclaimed spare parts.

Conceptual demonstration of a Lego-like modular fabrication method for an engineering model of a small monopropellant PCB thrusters

We present an innovative modular fabrication method for a green monopropellant thruster, employing printed circuit boards (PCB) as fundamental building blocks for rapid and efficient performance optimization. This PCB-based approach offers superior thermal and structural characteristics to conventional MEMS-based microthrusters. Furthermore, it streamlines mass production and facilitates the swift and reliable assembly of thrusters using well-established PCB surface mount technology. In this study, we present a conceptual demonstration of this pioneering materials and fabrication technique, exemplified by the development of a 200 mN thrust monopropellant thruster utilizing 90 wt% hydrogen peroxide. Subsequently, we conduct propulsion experiments and consistently observe identical patterns in pulse mode firing tests, demonstrating the repeatability of the system. The experimental results, including thrust and C* efficiencies, provide substantial evidence for the validity and feasibility of our proposed approach. The modular fabrication method presented in this study exhibits high potential for mass production of small satellite thrusters, effectively addressing the expanding thruster market.

Sensitizing Explosives Through Molecular Doping.

Cocrystallization assembles multicomponent crystals in defined ratios that are held together by intermolecular interactions. While cocrystals have seen extensive use in the pharmaceutical industry for solving issues with stability and solubility, extension to the field of energetic materials for improved properties has proven difficult. Predicting successful coformers remains a challenge for systems lacking well-understood synthons that promote reliable intermolecular assembly. Herein, an alternative method is investigated for altering energetic properties that operates in the absence of well-defined interactions by molecular doping. An impact sensitive primary explosive, cyanuric triazide (CTA), was selected as the dopant to test if less impact sensitive secondary explosives could gain increased sensitization to impact when CTA is inserted into their crystal lattices. Molecular doping was successful in sensitizing three melt-castable energetics: 2,4,6-trinitrotoluene (TNT), 2,4-dinitroanisole (DNAN), and 1,3,3-trinitroazetidine (TNAZ). CTA could also be incorporated as a stabilized inclusion to sensitize DNAN further. These results demonstrate how the judicious choice of dopant can lead to specific property improvements, providing a method for creating energetic materials with new properties to access metal-free primary explosives and physical hot spot models for explosive ignition.

Evaluation of reliability indicators of shock absorbers struts of M1 category cars in conditions of violation of established market relations between end users of spare parts and suppliers

Introduction. Over the past two years, there has been a violation of established market relations between end users of spare parts and suppliers. This led, on the one hand, to a significant increase in the cost of automotive components, and, on the other, to a reorientation of the market to new alternative manufacturers and suppliers. The main purpose of the work was a statistical assessment of the reliability indicators of the most expensive suspension element – the McPherson suspension strut, in the conditions of replacing the original struts with analogues available on the market.Methods. The study of the operational reliability of systems, components and assemblies of M1 cars was conducted in a dealership during 2022-2023. The study mainly involved cars with a sedan body and a McPherson front suspension. At the same time, the reason for contacting the service, the mileage of the car, as well as the types of work performed were recorded in each work order. The experimental data were processed using MSExcel and MatLab software from MathWorks.Resultsand conclusions. The conducted research allowed us to conclude that the appeals on the suspension of the car are almost twice as high as other appeals. The most expensive elements – the front shock struts, account for up to a third of all suspension failures. To assess the reliability indicators of alternative racks, the failure distribution law (normal), the probability of failure and uptime are determined, and the parameters of the distribution law are determined: mathematical expectation, standard deviation and coefficient of variation. It was found that the resource of the rear shock absorbers is at least 30% more, and there are significantly fewer calls at the service station. Thus, the operation of a car with racks from alternative manufacturers is quite reasonable, despite the fact that the resource of racks from alternative manufacturers is usually lower than that of the original brands.

Interconnect Stress Testing as a Tool for Assessment of Reliability of Modern PCBs

The of miniaturization can be seen in electronics for some time already. The pinout of active components grows enabling them to have additional functions. The trend in usage of System in a Package (SiP) solutions is also evident thus routing of the active and passive elements became also challenging. To overcome this challenge boards with High Density Interconnection (HDI) where not only through hole, but also different kinds of microvias e.g. blind, buried, stacked, staggered via are used. The standard procedure to test reliability of boards and assemblies is very resource-hungry especially in time and money, as the tests have to be carried out in climatic chambers which lasts for weeks, followed by additional destructive testing like cross-sections. On the other hand IST (Interconnect Stress Testing) is a quick test, that enables to have assessment of the used technology especially the quality of the through holes of all types. Although the coupons are destroyed during the test, it is not necessary to test the manufactured circuits. This saves both materials and time. The technology optimizations and the key findings will be presented within the paper.