Self-Powered Triboelectric Vibration Sensor for Non-Destructive Density Evaluation of Metal 3D-Printed Parts

Self-Powered Triboelectric Vibration Sensor for Non-Destructive Density Evaluation of Metal 3D-Printed Parts | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Self-Powered Triboelectric Vibration Sensor for Non-Destructive Density Evaluation of Metal 3D-Printed Parts Young Won Kim, Jiyong Park This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7521617/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 5 You are reading this latest preprint version Abstract In this study, a self-powered triboelectric vibration sensor (TVS) was designed and fabricated to enable non-destructive evaluation of the density of metal 3D-printed specimens. The developed TVS employed a rigid glass substrate combined with an aluminum friction electrode and an electrospun PVDF-TrFE nanofiber layer, which together established a contact-separation-based triboelectric conversion mechanism. The nanofiber layer, characterized by its high porosity and flexibility, was engineered to increase the effective contact area and enhance the sensing sensitivity, while also functioning as a structural cushion to improve mechanical durability. Using this sensor, the vibration attenuation characteristics of metal 3D-printed specimens with different densities (10%, 60%, and 100%) were measured. Under test conditions of 200 Hz frequency and 50 µm amplitude, the results demonstrated a clear linear correlation between the specimen density and the degree of vibration attenuation. The relationship between the TVS output voltage and specimen density was quantified with a coefficient of determination (R²) of 0.984, confirming the feasibility of accurate density estimation. These findings indicate that the triboelectric sensor can be extended beyond conventional energy harvesting applications into a practical sensing platform capable of industrial use in structural health monitoring and quality assessment of 3D-printed components. Furthermore, this study provides a concrete example of how TENG technology can contribute to broader commercialization and adoption by demonstrating low-cost, battery-free, and lightweight advantages that enable deployment across diverse industrial settings. Triboelectric Vibration Sensor (TVS) Laser Powder Bed Fusion Specimens Non-Destructive Evaluation Self-Powered Sensor Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 1. Introduction The accelerating pace of industrialization and technological advancement worldwide has precipitated an unprecedented surge in energy consumption, thereby intensifying concerns over the depletion of conventional fossil fuel resources 1 – 3 . This global energy challenge has galvanized extensive research into alternative technologies capable of supporting sustainable and resilient energy infrastructures 4 – 6 . In this context, environmentally benign, self-powered nanogenerators have emerged as promising candidates for next-generation energy harvesting and sensing applications 7 – 9 . By converting ubiquitous ambient stimuli—including low-frequency mechanical vibrations, human motion, acoustic waves, and airflow—into usable electrical energy, nanogenerators are being actively explored for integration into wearable electronics, Internet of Things (IoT) devices, and structural health monitoring (SHM) systems 10 – 12 . Among these emerging technologies, triboelectric nanogenerators (TENGs) have gained particular prominence due to their inherently simple architecture, broad material compatibility, and ability to efficiently transduce mechanical energy without relying on external power supplies 13 – 15 . TENGs operate on the fundamental principle of the triboelectric effect, wherein repetitive contact and separation between two dissimilar materials induce charge transfer at their interfaces, thereby generating measurable electrical signals. Owing to their high open-circuit voltage, lightweight form factors, and ease of customization, TENGs have demonstrated considerable potential as both energy harvesters and self-sustaining sensors across diverse application domains 16 – 18 . Recent advances in this field have underscored the pivotal role of material engineering and structural design in achieving high-output and high-sensitivity TENG devices. In particular, the adoption of electrospun nanofiber layers as friction surfaces has been shown to significantly enhance triboelectric performance by increasing the effective contact area and promoting charge generation 19 – 21 . Nanofibrous architectures exhibit exceptionally high surface-area-to-volume ratios and porosity, facilitating efficient interfacial interactions during contact-separation cycles. Notably, polymeric materials such as PVDF-TrFE have been extensively utilized as negative friction layers due to their strong electron affinity, mechanical robustness, and inherent flexibility 20 , 22 . Parallel to the evolution of materials and device configurations, substantial efforts have been devoted to leveraging the triboelectric mechanism for advanced sensing applications. TENG-based sensors have progressed well beyond their origins as pure energy transducers and are now being actively investigated for a wide range of functionalities, including environmental monitoring, biosignal detection, and the precise characterization of dynamic mechanical stimuli 23 , 24 . Their intrinsic self-powered nature—requiring no external energy input—renders TENG sensors highly attractive for the development of compact, sustainable, and maintenance-free sensing platforms. Consequently, a broad spectrum of sensor modalities exploiting sliding, contact-separation, and freestanding operational modes has been reported 25 . Amid these developments, vibration sensing has emerged as a particularly relevant yet technically demanding target for TENG-based devices. Vibration phenomena are pervasive across industrial machinery, civil infrastructures, and biological systems, and the accurate quantification of vibration parameters—such as amplitude, frequency, and damping characteristics—is critical for predictive maintenance, process optimization, and operational safety. However, conventional vibration sensors frequently entail high costs, complex installation, and dependence on external power sources, thereby motivating the exploration of self-powered triboelectric vibration sensors as a compelling alternative 26 , 27 . Concurrently, metal additive manufacturing (AM) has rapidly matured into a transformative fabrication technology that offers the ability to produce geometrically complex, high-precision metal components with unprecedented design freedom. As the adoption of metal 3D printing accelerates across high-value sectors such as aerospace, biomedical devices, and defense applications, the need for reliable methods to assess internal density and detect hidden defects has become increasingly pronounced 28 , 29 . The density of additively manufactured parts directly influences their mechanical strength, thermal performance, and long-term durability, yet it remains highly sensitive to process parameters such as powder deposition uniformity, laser energy input, and melt pool dynamics 30 . At present, the assessment of density in metal AM components predominantly relies on techniques such as computed tomography (CT), Archimedes’ principle, or destructive cross-sectional analysis 30 , 31 . While effective in certain scenarios, these methods are often labor-intensive, costly, and inherently limited in their applicability to small, intricate, or lattice-structured parts 32 . Such limitations underscore the critical need for simple, rapid, and non-destructive sensing techniques capable of delivering repeatable density evaluations with minimal operational overhead 28 , 33 . Against this backdrop, the present study introduces a self-powered triboelectric vibration sensor (TVS) specifically designed to estimate the density of metal 3D-printed specimens by analyzing their vibration attenuation characteristics under controlled excitation. The proposed device integrates a rigid glass substrate to provide mechanical stability, an aluminum friction electrode for effective charge conduction, and an electrospun PVDF-TrFE nanofiber layer configured in a contact-separation mode to maximize triboelectric output. With its compact, lightweight construction and capacity for fully autonomous operation without external power input, the TVS was systematically validated through a series of controlled vibration experiments in conjunction with high-precision laser displacement measurements. The results of this investigation revealed a clear, linear correlation between the TVS output voltage and the density of specimens with differing porosities, enabling the development of a quantitative model for non-destructive density estimation. By demonstrating the feasibility of deploying TENG-based sensors as practical diagnostic tools in metal additive manufacturing workflows, this work highlights their broader potential to contribute to sustainable, energy-autonomous sensing technologies across industrial applications. Moreover, the proposed approach represents an important step toward translating TENG research beyond laboratory-scale prototypes and into real-world implementations capable of improving manufacturing quality, reducing operational costs, and advancing the adoption of green, self-powered sensing solutions. 2. Materials and methods 2.1 Fabrication of the Triboelectric Vibration Sensor Among the various substrate materials evaluated as the structural foundation for the triboelectric vibration sensor (TVS), a rigid glass substrate was ultimately selected. The primary objective of this study was to develop a sensor capable of maintaining structural integrity under sustained and variable vibrational loads while delivering consistent electrical output 22 . Compared to alternative substrate materials, glass exhibits excellent hardness and mechanical stability, ensuring that transmitted vibrations are conveyed to the active layers with minimal energy loss. Furthermore, glass functions as an effective electrical insulator under ambient conditions, facilitating efficient and unobstructed transfer of induced charges from the active layers directly to the electrodes without leakage or interference 34 , 35 . Based on these considerations, glass was deemed an appropriate substrate material for the contact–separation operational mode adopted in this sensor design. The TVS was configured to operate under conditions in which externally applied vibrations would drive the active layers into periodic contact and separation cycles, thereby generating triboelectric charge transfer. The overall material selection and structural configuration of the device are presented schematically in Fig. 1 (a). The lower portion of the device incorporates the positive layer, which serves the dual function of the positive friction material and the electrode. Aluminum was selected for this role due to its widespread use as an effective positive triboelectric material as well as its high electrical conductivity, ensuring efficient transport of harvested charges to the external circuit. To prevent interfacial discontinuities and avoid impediments to charge flow between dissimilar materials, the aluminum film was integrated to function simultaneously as both the friction layer and the electrode 36 – 38 . In contrast, the negative layer, located on the upper side of the device, was fabricated using a PVDF-based material known for its strong electron affinity and effective triboelectric performance when paired with aluminum. In particular, PVDF-TrFE in nanofiber matrix form has been widely reported to significantly enhance triboelectric output owing to its high porosity and extensive surface area 39 . The porous nanofiber structure compresses readily upon contact, increasing the effective interfacial area and maximizing charge generation. This property directly contributes to the improved sensitivity of the triboelectric sensor 39 , 40 . Furthermore, the deformable nanofiber mat acts as a cushioning layer between the rigid glass substrate and the positive electrode, effectively mitigating mechanical impact and enhancing the device’s durability under cyclic loading 22 . In light of these advantages, PVDF-TrFE nanofibers were adopted as the negative layer to provide both charge transfer functionality and structural protection 41 . The nanofiber matrix was prepared via electrospinning, which is widely recognized for producing uniform, defect-minimized nanofiber films with controllable morphology. For this process, PVDF-TrFE powder (70/30 molar ratio, Piezotech, France) was dissolved in a mixed solvent of dimethylformamide (DMF) and acetone in a 4:6 volume ratio to form a 14% (w/v) solution. The prepared solution was electrospun using a 25-gauge metallic needle (inner diameter: 0.26 mm) under an applied voltage of 21 kV for 30 minutes. The distance between the needle tip and the collector was maintained at 150 mm, and the polymer solution was delivered at a flow rate of 60 µL/min. Once fabricated, the nanofiber negative layer was arranged to contact the aluminum positive layer, facilitating electron transfer during the contact–separation process. When separation occurs, the depleted electrons are replenished through the aluminum electrode, which was also selected as the electrode material for the negative layer due to its reliable conductivity and material compatibility. Figure 1 (b) shows the assembled TVS device. The active layers, each measuring 20 mm × 20 mm, were affixed to the inner surfaces of two glass substrates facing each other. To enable controlled contact–separation motion during vertical vibration, elastic porous adhesive materials were attached to both ends of the assembly as spacers. The initial gap distance between the positive and negative layers was set to 1.5 mm, a separation known to optimize electron transfer and output performance during triboelectric operation. The operational mechanism of the TVS is illustrated in Fig. 1 (c). When external vibrational energy compresses the device, the two active layers are brought into contact, inducing the accumulation of positive and negative charges on their respective surfaces due to their differing triboelectric polarities. Upon release, electrons migrate from the positively charged aluminum layer to the negative layer to re-establish electrical equilibrium, generating the first electrical signal. Once complete separation is achieved, the system remains electrostatically balanced until the next compression cycle. When the active layers are again driven into proximity by subsequent vibrations, the potential difference induces the reverse migration of excess electrons from the negative layer back to the positive layer, producing a second electrical signal of opposite polarity. This process reflects the canonical contact–separation triboelectric mechanism, which in this study is harnessed to transduce vibration energy into electrical output 42 . A three-dimensional representation of the assembled TVS is presented in Fig. 1 (d). 2.2 Specimen Preparation and Experimental Setup The primary objective of this study was to evaluate the feasibility of using the triboelectric vibration sensor (TVS) for non-destructive density assessment of metal 3D-printed specimens. To this end, cubic specimens measuring 40 mm on each side were designed and fabricated with three different target densities of 100%, 60%, and 10%, enabling systematic comparison across a representative range of porosities. Figure 2 (a) illustrates the reference models: a fully dense solid cube (100% density), and two geometrically optimized lightweight models designed to achieve 60% and 10% of the baseline mass, respectively. These models incorporated internal lattice structures generated via Design for Additive Manufacturing (DfAM) principles, capitalizing on the capabilities of metal 3D printing to realize complex porous geometries that are not attainable by conventional manufacturing methods, while Fig. 2 (b) shows the actual printed reference specimens fabricated according to these designs. The specimens were fabricated using a ProX 300 system (3D Systems, USA) with 17-4PH stainless steel (commonly referred to as SUS 630) powder as the feedstock material. The process parameters were configured based on manufacturer-recommended values known to yield high build reliability and structural integrity. Specifically, the laser power was set to 135 W, the scanning speed to 1200 mm/s, the hatch spacing to 50 µm, and the layer thickness to 40 µm. Based on these settings, the volumetric energy density was calculated to be 56.250 J/mm³, which falls within the recommended process window for producing defect-minimized parts in SUS 630 alloys. The experimental setup devised to measure the vibration response of the fabricated specimens using the TVS is depicted in Fig. 3 (a). An arbitrary function generator supplied the input excitation signal, which was amplified and transmitted to an electrodynamic shaker. The shaker imparted controlled vibrations to the mounted specimen according to predefined amplitude and frequency parameters. Each 3D-printed specimen was rigidly fixed to the shaker platform, and the TVS was subsequently attached to the top surface of the specimen to record the vibration-induced triboelectric output. During operation, the applied vibration propagated through the specimen, which, depending on its density and internal damping characteristics, exhibited attenuated displacement amplitudes relative to the input signal. The core objective of this experimental system was to accurately quantify this attenuation behavior as a function of specimen density. To this end, the TVS was positioned to detect dynamic motion at the specimen surface and convert the mechanical stimulus into electrical signals via the triboelectric effect. The resulting voltage outputs were captured and analyzed using an oscilloscope. Additionally, a laser displacement sensor was aligned with the top surface of each specimen to provide independent, high-precision reference measurements of vibrational amplitude. This allowed for cross-validation of the TVS signals and ensured that the observed output characteristics were directly attributable to variations in specimen density and vibration attenuation behavior. 3. Results and discussion 3.1 Validation of TVS Functionality and Frequency Response Using Laser Displacement Measurements Prior to evaluating the capacity of the triboelectric vibration sensor (TVS) to differentiate the damping characteristics of metal 3D-printed specimens with varying densities, it was essential to first establish that the device could reliably transduce mechanical excitation into consistent and interpretable electrical output. This foundational step was particularly important in confirming that the sensor performance remained stable across a representative spectrum of vibration frequencies and amplitudes relevant to structural monitoring applications 43 . To accomplish this, the TVS was initially mounted directly onto the shaker platform without any intervening specimen. This configuration provided a controlled environment in which the inherent sensitivity, baseline noise characteristics, and linearity of the sensor could be rigorously evaluated. The arbitrary waveform generator was programmed to execute a two-part test sequence composed of a frequency sweep and a decibel step-response protocol. The frequency sweep aimed to determine the operational bandwidth of the sensor, while the decibel test was designed to confirm its amplitude resolution and linearity 44 . During the frequency sweep, the amplifier gain was fixed at 50 dB to ensure uniform excitation magnitude. Vibration initiation began from a stationary state, with incremental increases of 100 Hz every 5 seconds. The resulting output, as shown in Fig. 4 (a), revealed that at frequencies below 100 Hz, the sensor exhibited only minor fluctuations largely attributable to environmental electrical noise and the absence of preamplification or filtering circuitry. However, once the frequency surpassed 100 Hz, the output voltage displayed a marked and repeatable increase in amplitude with each frequency increment. This trend was sustained up to approximately 500 Hz, beyond which the output amplitude plateaued and ultimately stabilized near 0.4 V peak-to-peak as frequencies exceeded 1000 Hz. This response curve clearly demonstrates that the TVS possesses a dynamic sensitivity profile, with a well-defined linear operational range extending from approximately 100 Hz to 500 Hz. Within this window, incremental changes in frequency produced proportionate increases in output signal magnitude, underscoring the sensor’s potential for quantitative displacement estimation. This property is of practical significance, as the linearity of the frequency response facilitates calibration of the sensor output to known mechanical displacements, thereby enabling its deployment as a viable substitute for more costly displacement transducers. In addition to frequency response evaluation, a decibel step-response protocol was conducted to assess the sensor’s ability to resolve discrete amplitude changes. Operating under a fixed excitation frequency of 1000 Hz, the shaker alternated between 5-second intervals of 50 dB excitation and quiescent phases, repeated three times to confirm consistency. Following this, the amplitude was increased by 10 dB increments every 5 seconds until reaching 100 dB. The output voltage traces in Fig. 4 (b) exhibit a highly predictable and linear relationship between excitation amplitude and sensor response, with no evidence of compression or nonlinearity throughout the tested range. Importantly, this phase of the experiment revealed that the TVS maintained consistent signal fidelity across multiple excitation cycles and amplitude levels, reinforcing its suitability for applications where stable and repeatable measurements are critical 45 . The sensor’s performance in this context suggests that it is not only sensitive to subtle variations in mechanical excitation but also robust against transient perturbations that might otherwise compromise measurement accuracy 46 45 . Furthermore, the reproducibility of the response under repeated load cycles indicates a high degree of mechanical durability in the sensor assembly, a characteristic essential for practical deployment in industrial monitoring environments where sustained vibration exposure is expected. 3.2 Density-Dependent Vibration Attenuation Characterization Following confirmation of the sensor’s baseline performance, the study advanced to the characterization of vibration attenuation as a function of specimen density. For this purpose, three cubic specimens measuring 40 mm per side were fabricated using metal additive manufacturing, with nominal target densities of 10%, 60%, and 100%. The controlled variation of density was achieved by introducing internal lattice geometries of differing volume fractions while maintaining identical external dimensions, thus isolating the effect of density on mechanical damping behavior. During experimentation, each specimen was rigidly mounted to the shaker platform, and a series of excitation frequencies were applied to identify regimes in which density-dependent attenuation became prominent. Laser displacement measurements were conducted in parallel to TVS readings, providing an independent validation dataset against which the sensor’s performance could be benchmarked. Figure 5 (a) through 5(f) present representative displacement time series collected from the shaker and the fully dense specimen across excitation frequencies ranging from 10 Hz to 1000 Hz. In the lower frequency bands (10–50 Hz), minimal divergence was observed between the shaker’s output and the specimen’s transmitted vibration, indicating that inertial mass and internal damping effects were insufficient to produce measurable attenuation at these frequencies. However, at 100 Hz (Fig. 5 (d)), the displacement amplitude of the 100% density specimen decreased markedly compared to the shaker reference. This pronounced attenuation is attributed to the increased mass and internal frictional dissipation within the fully dense lattice, which act synergistically to reduce the transmitted vibrational energy. The identification of this attenuation threshold was a critical outcome of the study, as it established an empirical basis for selecting excitation parameters likely to produce quantifiable differences among specimens of varying densities 47 . Prior studies have demonstrated similar attenuation phenomena in metal lattice structures subjected to harmonic excitation, suggesting that the results obtained here are consistent with established mechanical behavior. Building upon this observation, a more focused investigation was conducted to quantify the degree of attenuation under excitation frequencies of 100 Hz and 200 Hz, combined with displacement amplitudes of 25 µm and 50 µm. The displacement data consolidated in Fig. 6 reveal that while all configurations exhibited some degree of attenuation relative to the shaker baseline, the 200 Hz, 50 µm condition provided the most pronounced differentiation among the specimens. Under this regime, the shaker maintained a stable displacement amplitude of 50 µm, while the 10% density specimen displayed an attenuated amplitude of 30 µm, the 60% specimen 26 µm, and the 100% specimen further reduced to 17 µm. This clear inverse relationship between specimen density and transmitted displacement amplitude demonstrates the feasibility of using vibration-based measurements as a non-destructive method for estimating internal density in additively manufactured metal components. The attenuation is understood to arise from a combination of increased stiffness, higher effective mass, and enhanced internal friction within the denser structures, all of which contribute to greater energy dissipation during dynamic loading. Moreover, the strong consistency of the measured attenuation across repeated trials highlights the reliability of the test protocol and the reproducibility of the results. This robustness is critical if the method is to be adopted for routine quality control in industrial manufacturing environments. 3.3 Validation of TVS-Based Density Estimation The final phase of the study involved assessing whether the TVS could replicate the discrimination capability of the laser displacement sensor under identical excitation conditions. The sensor was mounted atop each specimen in turn, and its output voltage was recorded during controlled vibration at the same frequencies and amplitudes previously used for displacement measurements. Figure 7 (a) displays representative voltage waveforms obtained from the TVS across all specimens. Consistent with the displacement data, the triboelectric output amplitude decreased proportionally as specimen density increased, indicating that the sensor successfully transduced the density-dependent attenuation into electrical signals. This observation is particularly significant, as it demonstrates that the TVS is sensitive not only to gross vibration magnitude but also to subtle variations induced by changes in specimen mass and stiffness. The comparative analysis presented in Fig. 7 (b) plots the peak-to-peak TVS output voltage against the corresponding displacement amplitudes measured by the laser sensor. Regression analysis yielded a coefficient of determination (R²) of 0.88979, confirming that the TVS output exhibits a strong linear correlation with actual mechanical displacement. This high degree of correlation validates the sensor’s capability to function as a surrogate measurement device for estimating specimen density in a non-destructive manner. Although the absolute displacement resolution of the TVS is lower than that of the laser displacement sensor, its substantial advantages in terms of cost-effectiveness, mechanical simplicity, and self-powered operation render it an attractive option for practical deployment. The device’s reliance on triboelectric charge generation obviates the need for external power supplies or signal conditioning circuitry, reducing system complexity and maintenance requirements 48 . Furthermore, the fabrication methodology, based primarily on electrospinning and thin-film deposition, is readily scalable and adaptable to a variety of substrate materials and geometries. This manufacturing flexibility enhances the potential for widespread adoption of the TVS in diverse industrial sectors 49 , 50 . Importantly, the sensor’s performance in these experiments suggests that triboelectric mechanisms can be harnessed not only for energy harvesting but also for advanced sensing applications that traditionally rely on more complex transducers 51 . This dual functionality aligns with the emerging paradigm of multifunctional nanogenerator systems capable of serving both as power sources and as self-powered sensor platforms. Future work will focus on further refining the sensitivity and resolution of the TVS through optimization of material composition, surface microstructure, and electrode configuration. Additionally, efforts will be directed toward integrating the sensor into automated inspection workflows for real-time monitoring of additive manufacturing processes. The potential to combine triboelectric sensing with machine learning algorithms for predictive quality assessment represents a particularly promising avenue of research. Collectively, these findings demonstrate that the triboelectric vibration sensor developed in this study offers a viable and innovative approach to non-destructive density estimation of metal 3D-printed components, with broader implications for sustainable manufacturing practices and the evolution of smart, self-powered sensing technologies. 4. Conclusion In this study, a self-powered triboelectric vibration sensor (TVS) based on the contact–separation mechanism was developed and demonstrated as a novel approach for non-destructive density estimation of metal 3D-printed specimens. The device architecture employed a glass substrate supporting aluminum and electrospun PVDF-TrFE nanofiber layers, enabling effective triboelectric charge generation without any external power supply. Through systematic experiments involving vibration excitation across specimens with distinct densities (10%, 60%, and 100%), the TVS was shown to produce output voltages exhibiting a strong linear correlation with specimen density. Under the 200 Hz, 50 µm excitation condition, the sensor output demonstrated clear separation among the three densities, achieving a coefficient of determination (R²) of 0.984, thereby validating its capacity for quantitative estimation. These results highlight the potential of triboelectric sensors to evolve beyond their traditional role as energy harvesters or simple motion detectors, demonstrating feasibility as material property estimation tools capable of providing meaningful feedback about internal structural characteristics. Importantly, the TVS developed here embodies several attributes—simplicity, lightweight construction, low production cost, and complete energy autonomy—that position it as a promising alternative or complementary technology to existing non-destructive evaluation systems, which are often costly and complex. This versatility suggests strong potential for integration not only in additive manufacturing quality assurance but also in broader applications such as structural health monitoring, industrial machinery maintenance, and distributed sensing networks. Most critically, the advancement of triboelectric nanogenerator (TENG) technology toward widespread commercialization and real-world adoption requires compelling examples of practical, value-adding applications. The TVS presented in this work serves as a representative case demonstrating that triboelectric mechanisms can be harnessed to create viable sensor platforms, bridging the gap between laboratory research and industry-ready solutions. By contributing to improved manufacturing efficiency, cost reduction, and enhanced confidence in sensor reliability, this approach offers a tangible pathway for TENG-based devices to achieve broader deployment and to become embedded in daily life as practical, sustainable technologies. Declarations a. Funding This research was supported by the Ministry of Trade, Industry and Energy of Korea through the project “Development of 3D Printing Digital Transformation Platform Technology Based on Process Metadata” (KM250130), and by the Korea Institute of Industrial Technology (KITECH) through its in-house research project “AI-Based Real-Time Digital Transformation and Process Optimization of AM Operations” (UR250009). b. Conflicts of interest/Competing interests Not applicable c. Authors' contributions Young Won Kim contributed by proposing the original idea of the study and leading the overall experimental process, from designing and conducting the tests to analyzing the data, while also taking primary responsibility for drafting and structuring the manuscript to ensure that the research objectives were clearly conveyed. Jiyong Park contributed by refining the logical flow of the manuscript and planning the experimental approach based on prior references, actively engaging in the experimental validation, and focusing on reviewing and revising the paper to guarantee both scientific accuracy and overall coherence. References Dresselhaus, M. S. & Thomas, I. Alternative energy technologies. Nature 414 , 332–337 (2001). Awogbemi, O., Kallon, D., Owoputi, A. & Mansaray, K. Sustainable Energy Consumption in the Industry 4.0 era. Nowotny, J. et al. 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Journal of sound and vibration 11 , 3–IN1 (1970). Lee, H. B., Kim, Y. W., Yoon, J., Lee, N. K. & Park, S.-H. 3D customized and flexible tactile sensor using a piezoelectric nanofiber mat and sandwich-molded elastomer sheets. Smart Materials and Structures 26 , 045032 (2017). Garcia, Y. R., Corres, J. M. & Goicoechea, J. Vibration detection using optical fiber sensors. Journal of Sensors 2010 , 936487 (2010). Jati, M. P. et al. A Deep Learning Framework for Enhancing High-Frequency Optical Fiber Vibration Sensing from Low-Sampling-Rate FBG Interrogators. Sensors 25 , 4047 (2025). Furuya, O. & Kurabayashi, H. in ASME Pressure Vessels and Piping Conference. 171–176. Mallineni, S. S. K., Dong, Y., Behlow, H., Rao, A. M. & Podila, R. A wireless triboelectric nanogenerator. Advanced Energy Materials 8 , 1702736 (2018). Yang, P. K. et al. A flexible, stretchable and shape‐adaptive approach for versatile energy conversion and self‐powered biomedical monitoring. Advanced Materials 27 , 3817–3824 (2015). Wang, H. et al. Ultralight, scalable, and high-temperature–resilient ceramic nanofiber sponges. Science advances 3 , e1603170 (2017). Zhu, J. et al. Progress in TENG technology—A journey from energy harvesting to nanoenergy and nanosystem. EcoMat 2 , e12058 (2020). Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Major Revisions Needed 16 Nov, 2025 Reviewers agreed at journal 21 Sep, 2025 Reviewers invited by journal 20 Sep, 2025 Editor assigned by journal 11 Sep, 2025 First submitted to journal 07 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7521617","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":518086182,"identity":"08439a63-05e4-4759-a318-35c7bc761a34","order_by":0,"name":"Young Won 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1","display":"","copyAsset":false,"role":"figure","size":345610,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Schematic diagram of the triboelectric vibration sensor (TVS) showing the rigid glass substrates, aluminum positive layer serving as both friction material and electrode, and the PVDF-TrFE nanofiber negative layer fabricated by electrospinning. (b) Photograph of the assembled TVS device with elastic spacers to enable controlled contact–separation cycles. (c) Illustration of the operational mechanism in which external vibration induces periodic charge transfer between the active layers. (d) Three-dimensional representation of the fully assembled TVS.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7521617/v1/8eee64a80540e0a14f3dc5ac.png"},{"id":92572293,"identity":"06a9fa49-ee30-4730-b8ea-3710fd81ce5b","added_by":"auto","created_at":"2025-10-01 07:57:24","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":278301,"visible":true,"origin":"","legend":"\u003cp\u003e(a) CAD models of 3D-printed metal specimens with target densities of 100%, 60%, and 10%, incorporating lattice structures designed via Design for Additive Manufacturing (DfAM). (b) Photograph of the fabricated stainless steel specimens produced using selective laser melting.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7521617/v1/78f42092b01fffa0564b500f.png"},{"id":92572295,"identity":"8b01ca3c-6c65-4b16-9109-1f33d802b10e","added_by":"auto","created_at":"2025-10-01 07:57:24","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":748064,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic of the experimental setup for vibration testing. An electrodynamic shaker driven by an arbitrary waveform generator applies controlled vibrations to the mounted specimen, while the TVS mounted on the specimen surface transduces dynamic motion into electrical output. A laser displacement sensor is aligned to acquire reference measurements of displacement amplitude.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7521617/v1/3910caafcd3da23cf0b7726d.png"},{"id":92572294,"identity":"ef737561-7933-47c6-989a-7da767aa1c78","added_by":"auto","created_at":"2025-10-01 07:57:24","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":95212,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Frequency response of the TVS mounted directly on the shaker platform during a frequency sweep from 10 Hz to 1000 Hz at constant excitation amplitude. The output demonstrates linear sensitivity between 100 Hz and 500 Hz. (b) Decibel step-response of the TVS under fixed 1000 Hz excitation, illustrating the linear relationship between excitation amplitude and output voltage.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7521617/v1/c8c88097016f3fcb2b4b5d62.png"},{"id":92572792,"identity":"3f08ef13-558d-424a-9621-ac282fdaa733","added_by":"auto","created_at":"2025-10-01 08:05:24","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":789209,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative displacement waveforms measured by the laser displacement sensor across excitation frequencies from 10 Hz to 1000 Hz.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-7521617/v1/62268cc1d75a71af59242dd7.png"},{"id":92572796,"identity":"0adccf3a-98f2-4834-bd24-d54e8e530874","added_by":"auto","created_at":"2025-10-01 08:05:24","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":692409,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of displacement attenuation across specimens with different densities under controlled excitation conditions (100 Hz and 200 Hz; 25 μm and 50 μm amplitudes).\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-7521617/v1/931d7981319e5659fd736847.png"},{"id":92575462,"identity":"e601a8a8-a819-4a13-b699-e57cf8a0980e","added_by":"auto","created_at":"2025-10-01 08:21:24","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":189119,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Representative TVS output voltage waveforms acquired during vibration tests of specimens with different densities. (b) Correlation plot comparing peak-to-peak TVS output voltage and displacement amplitudes measured by the laser displacement sensor.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-7521617/v1/dafef3149e2ad44873a31be7.png"},{"id":92600401,"identity":"6a1be9e0-6187-4e9a-a871-33c6c4491667","added_by":"auto","created_at":"2025-10-01 14:22:15","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3729198,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7521617/v1/961a0304-ae38-4fdc-a0fe-3b4a81a41222.pdf"}],"financialInterests":"","formattedTitle":"Self-Powered Triboelectric Vibration Sensor for Non-Destructive Density Evaluation of Metal 3D-Printed Parts","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe accelerating pace of industrialization and technological advancement worldwide has precipitated an unprecedented surge in energy consumption, thereby intensifying concerns over the depletion of conventional fossil fuel resources \u003csup\u003e\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. This global energy challenge has galvanized extensive research into alternative technologies capable of supporting sustainable and resilient energy infrastructures \u003csup\u003e\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. In this context, environmentally benign, self-powered nanogenerators have emerged as promising candidates for next-generation energy harvesting and sensing applications \u003csup\u003e\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. By converting ubiquitous ambient stimuli\u0026mdash;including low-frequency mechanical vibrations, human motion, acoustic waves, and airflow\u0026mdash;into usable electrical energy, nanogenerators are being actively explored for integration into wearable electronics, Internet of Things (IoT) devices, and structural health monitoring (SHM) systems \u003csup\u003e\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eAmong these emerging technologies, triboelectric nanogenerators (TENGs) have gained particular prominence due to their inherently simple architecture, broad material compatibility, and ability to efficiently transduce mechanical energy without relying on external power supplies \u003csup\u003e\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. TENGs operate on the fundamental principle of the triboelectric effect, wherein repetitive contact and separation between two dissimilar materials induce charge transfer at their interfaces, thereby generating measurable electrical signals. Owing to their high open-circuit voltage, lightweight form factors, and ease of customization, TENGs have demonstrated considerable potential as both energy harvesters and self-sustaining sensors across diverse application domains\u003csup\u003e\u003cspan additionalcitationids=\"CR17\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eRecent advances in this field have underscored the pivotal role of material engineering and structural design in achieving high-output and high-sensitivity TENG devices. In particular, the adoption of electrospun nanofiber layers as friction surfaces has been shown to significantly enhance triboelectric performance by increasing the effective contact area and promoting charge generation \u003csup\u003e\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. Nanofibrous architectures exhibit exceptionally high surface-area-to-volume ratios and porosity, facilitating efficient interfacial interactions during contact-separation cycles. Notably, polymeric materials such as PVDF-TrFE have been extensively utilized as negative friction layers due to their strong electron affinity, mechanical robustness, and inherent flexibility \u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e,\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eParallel to the evolution of materials and device configurations, substantial efforts have been devoted to leveraging the triboelectric mechanism for advanced sensing applications. TENG-based sensors have progressed well beyond their origins as pure energy transducers and are now being actively investigated for a wide range of functionalities, including environmental monitoring, biosignal detection, and the precise characterization of dynamic mechanical stimuli \u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e,\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e. Their intrinsic self-powered nature\u0026mdash;requiring no external energy input\u0026mdash;renders TENG sensors highly attractive for the development of compact, sustainable, and maintenance-free sensing platforms. Consequently, a broad spectrum of sensor modalities exploiting sliding, contact-separation, and freestanding operational modes has been reported \u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eAmid these developments, vibration sensing has emerged as a particularly relevant yet technically demanding target for TENG-based devices. Vibration phenomena are pervasive across industrial machinery, civil infrastructures, and biological systems, and the accurate quantification of vibration parameters\u0026mdash;such as amplitude, frequency, and damping characteristics\u0026mdash;is critical for predictive maintenance, process optimization, and operational safety. However, conventional vibration sensors frequently entail high costs, complex installation, and dependence on external power sources, thereby motivating the exploration of self-powered triboelectric vibration sensors as a compelling alternative \u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e,\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eConcurrently, metal additive manufacturing (AM) has rapidly matured into a transformative fabrication technology that offers the ability to produce geometrically complex, high-precision metal components with unprecedented design freedom. As the adoption of metal 3D printing accelerates across high-value sectors such as aerospace, biomedical devices, and defense applications, the need for reliable methods to assess internal density and detect hidden defects has become increasingly pronounced\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. The density of additively manufactured parts directly influences their mechanical strength, thermal performance, and long-term durability, yet it remains highly sensitive to process parameters such as powder deposition uniformity, laser energy input, and melt pool dynamics \u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eAt present, the assessment of density in metal AM components predominantly relies on techniques such as computed tomography (CT), Archimedes\u0026rsquo; principle, or destructive cross-sectional analysis \u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e,\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e. While effective in certain scenarios, these methods are often labor-intensive, costly, and inherently limited in their applicability to small, intricate, or lattice-structured parts\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. Such limitations underscore the critical need for simple, rapid, and non-destructive sensing techniques capable of delivering repeatable density evaluations with minimal operational overhead \u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eAgainst this backdrop, the present study introduces a self-powered triboelectric vibration sensor (TVS) specifically designed to estimate the density of metal 3D-printed specimens by analyzing their vibration attenuation characteristics under controlled excitation. The proposed device integrates a rigid glass substrate to provide mechanical stability, an aluminum friction electrode for effective charge conduction, and an electrospun PVDF-TrFE nanofiber layer configured in a contact-separation mode to maximize triboelectric output. With its compact, lightweight construction and capacity for fully autonomous operation without external power input, the TVS was systematically validated through a series of controlled vibration experiments in conjunction with high-precision laser displacement measurements.\u003c/p\u003e\u003cp\u003eThe results of this investigation revealed a clear, linear correlation between the TVS output voltage and the density of specimens with differing porosities, enabling the development of a quantitative model for non-destructive density estimation. By demonstrating the feasibility of deploying TENG-based sensors as practical diagnostic tools in metal additive manufacturing workflows, this work highlights their broader potential to contribute to sustainable, energy-autonomous sensing technologies across industrial applications. Moreover, the proposed approach represents an important step toward translating TENG research beyond laboratory-scale prototypes and into real-world implementations capable of improving manufacturing quality, reducing operational costs, and advancing the adoption of green, self-powered sensing solutions.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Fabrication of the Triboelectric Vibration Sensor\u003c/h2\u003e\u003cp\u003eAmong the various substrate materials evaluated as the structural foundation for the triboelectric vibration sensor (TVS), a rigid glass substrate was ultimately selected. The primary objective of this study was to develop a sensor capable of maintaining structural integrity under sustained and variable vibrational loads while delivering consistent electrical output \u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. Compared to alternative substrate materials, glass exhibits excellent hardness and mechanical stability, ensuring that transmitted vibrations are conveyed to the active layers with minimal energy loss. Furthermore, glass functions as an effective electrical insulator under ambient conditions, facilitating efficient and unobstructed transfer of induced charges from the active layers directly to the electrodes without leakage or interference \u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e,\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e. Based on these considerations, glass was deemed an appropriate substrate material for the contact\u0026ndash;separation operational mode adopted in this sensor design.\u003c/p\u003e\u003cp\u003eThe TVS was configured to operate under conditions in which externally applied vibrations would drive the active layers into periodic contact and separation cycles, thereby generating triboelectric charge transfer. The overall material selection and structural configuration of the device are presented schematically in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(a).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe lower portion of the device incorporates the positive layer, which serves the dual function of the positive friction material and the electrode. Aluminum was selected for this role due to its widespread use as an effective positive triboelectric material as well as its high electrical conductivity, ensuring efficient transport of harvested charges to the external circuit. To prevent interfacial discontinuities and avoid impediments to charge flow between dissimilar materials, the aluminum film was integrated to function simultaneously as both the friction layer and the electrode \u003csup\u003e\u003cspan additionalcitationids=\"CR37\" citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eIn contrast, the negative layer, located on the upper side of the device, was fabricated using a PVDF-based material known for its strong electron affinity and effective triboelectric performance when paired with aluminum. In particular, PVDF-TrFE in nanofiber matrix form has been widely reported to significantly enhance triboelectric output owing to its high porosity and extensive surface area \u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e. The porous nanofiber structure compresses readily upon contact, increasing the effective interfacial area and maximizing charge generation. This property directly contributes to the improved sensitivity of the triboelectric sensor \u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e,\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e. Furthermore, the deformable nanofiber mat acts as a cushioning layer between the rigid glass substrate and the positive electrode, effectively mitigating mechanical impact and enhancing the device\u0026rsquo;s durability under cyclic loading\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eIn light of these advantages, PVDF-TrFE nanofibers were adopted as the negative layer to provide both charge transfer functionality and structural protection\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e. The nanofiber matrix was prepared via electrospinning, which is widely recognized for producing uniform, defect-minimized nanofiber films with controllable morphology. For this process, PVDF-TrFE powder (70/30 molar ratio, Piezotech, France) was dissolved in a mixed solvent of dimethylformamide (DMF) and acetone in a 4:6 volume ratio to form a 14% (w/v) solution. The prepared solution was electrospun using a 25-gauge metallic needle (inner diameter: 0.26 mm) under an applied voltage of 21 kV for 30 minutes. The distance between the needle tip and the collector was maintained at 150 mm, and the polymer solution was delivered at a flow rate of 60 \u0026micro;L/min.\u003c/p\u003e\u003cp\u003eOnce fabricated, the nanofiber negative layer was arranged to contact the aluminum positive layer, facilitating electron transfer during the contact\u0026ndash;separation process. When separation occurs, the depleted electrons are replenished through the aluminum electrode, which was also selected as the electrode material for the negative layer due to its reliable conductivity and material compatibility.\u003c/p\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(b) shows the assembled TVS device. The active layers, each measuring 20 mm \u0026times; 20 mm, were affixed to the inner surfaces of two glass substrates facing each other. To enable controlled contact\u0026ndash;separation motion during vertical vibration, elastic porous adhesive materials were attached to both ends of the assembly as spacers. The initial gap distance between the positive and negative layers was set to 1.5 mm, a separation known to optimize electron transfer and output performance during triboelectric operation.\u003c/p\u003e\u003cp\u003eThe operational mechanism of the TVS is illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(c). When external vibrational energy compresses the device, the two active layers are brought into contact, inducing the accumulation of positive and negative charges on their respective surfaces due to their differing triboelectric polarities. Upon release, electrons migrate from the positively charged aluminum layer to the negative layer to re-establish electrical equilibrium, generating the first electrical signal. Once complete separation is achieved, the system remains electrostatically balanced until the next compression cycle. When the active layers are again driven into proximity by subsequent vibrations, the potential difference induces the reverse migration of excess electrons from the negative layer back to the positive layer, producing a second electrical signal of opposite polarity. This process reflects the canonical contact\u0026ndash;separation triboelectric mechanism, which in this study is harnessed to transduce vibration energy into electrical output \u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e. A three-dimensional representation of the assembled TVS is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(d).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Specimen Preparation and Experimental Setup\u003c/h2\u003e\u003cp\u003eThe primary objective of this study was to evaluate the feasibility of using the triboelectric vibration sensor (TVS) for non-destructive density assessment of metal 3D-printed specimens. To this end, cubic specimens measuring 40 mm on each side were designed and fabricated with three different target densities of 100%, 60%, and 10%, enabling systematic comparison across a representative range of porosities. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(a) illustrates the reference models: a fully dense solid cube (100% density), and two geometrically optimized lightweight models designed to achieve 60% and 10% of the baseline mass, respectively. These models incorporated internal lattice structures generated via Design for Additive Manufacturing (DfAM) principles, capitalizing on the capabilities of metal 3D printing to realize complex porous geometries that are not attainable by conventional manufacturing methods, while Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(b) shows the actual printed reference specimens fabricated according to these designs.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe specimens were fabricated using a ProX 300 system (3D Systems, USA) with 17-4PH stainless steel (commonly referred to as SUS 630) powder as the feedstock material. The process parameters were configured based on manufacturer-recommended values known to yield high build reliability and structural integrity. Specifically, the laser power was set to 135 W, the scanning speed to 1200 mm/s, the hatch spacing to 50 \u0026micro;m, and the layer thickness to 40 \u0026micro;m. Based on these settings, the volumetric energy density was calculated to be 56.250 J/mm\u0026sup3;, which falls within the recommended process window for producing defect-minimized parts in SUS 630 alloys.\u003c/p\u003e\u003cp\u003eThe experimental setup devised to measure the vibration response of the fabricated specimens using the TVS is depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(a). An arbitrary function generator supplied the input excitation signal, which was amplified and transmitted to an electrodynamic shaker. The shaker imparted controlled vibrations to the mounted specimen according to predefined amplitude and frequency parameters. Each 3D-printed specimen was rigidly fixed to the shaker platform, and the TVS was subsequently attached to the top surface of the specimen to record the vibration-induced triboelectric output.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eDuring operation, the applied vibration propagated through the specimen, which, depending on its density and internal damping characteristics, exhibited attenuated displacement amplitudes relative to the input signal. The core objective of this experimental system was to accurately quantify this attenuation behavior as a function of specimen density. To this end, the TVS was positioned to detect dynamic motion at the specimen surface and convert the mechanical stimulus into electrical signals via the triboelectric effect. The resulting voltage outputs were captured and analyzed using an oscilloscope.\u003c/p\u003e\u003cp\u003eAdditionally, a laser displacement sensor was aligned with the top surface of each specimen to provide independent, high-precision reference measurements of vibrational amplitude. This allowed for cross-validation of the TVS signals and ensured that the observed output characteristics were directly attributable to variations in specimen density and vibration attenuation behavior.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Validation of TVS Functionality and Frequency Response Using Laser Displacement Measurements\u003c/h2\u003e\u003cp\u003ePrior to evaluating the capacity of the triboelectric vibration sensor (TVS) to differentiate the damping characteristics of metal 3D-printed specimens with varying densities, it was essential to first establish that the device could reliably transduce mechanical excitation into consistent and interpretable electrical output. This foundational step was particularly important in confirming that the sensor performance remained stable across a representative spectrum of vibration frequencies and amplitudes relevant to structural monitoring applications \u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eTo accomplish this, the TVS was initially mounted directly onto the shaker platform without any intervening specimen. This configuration provided a controlled environment in which the inherent sensitivity, baseline noise characteristics, and linearity of the sensor could be rigorously evaluated. The arbitrary waveform generator was programmed to execute a two-part test sequence composed of a frequency sweep and a decibel step-response protocol. The frequency sweep aimed to determine the operational bandwidth of the sensor, while the decibel test was designed to confirm its amplitude resolution and linearity \u003csup\u003e\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eDuring the frequency sweep, the amplifier gain was fixed at 50 dB to ensure uniform excitation magnitude. Vibration initiation began from a stationary state, with incremental increases of 100 Hz every 5 seconds. The resulting output, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a), revealed that at frequencies below 100 Hz, the sensor exhibited only minor fluctuations largely attributable to environmental electrical noise and the absence of preamplification or filtering circuitry. However, once the frequency surpassed 100 Hz, the output voltage displayed a marked and repeatable increase in amplitude with each frequency increment. This trend was sustained up to approximately 500 Hz, beyond which the output amplitude plateaued and ultimately stabilized near 0.4 V peak-to-peak as frequencies exceeded 1000 Hz.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThis response curve clearly demonstrates that the TVS possesses a dynamic sensitivity profile, with a well-defined linear operational range extending from approximately 100 Hz to 500 Hz. Within this window, incremental changes in frequency produced proportionate increases in output signal magnitude, underscoring the sensor\u0026rsquo;s potential for quantitative displacement estimation. This property is of practical significance, as the linearity of the frequency response facilitates calibration of the sensor output to known mechanical displacements, thereby enabling its deployment as a viable substitute for more costly displacement transducers.\u003c/p\u003e\u003cp\u003eIn addition to frequency response evaluation, a decibel step-response protocol was conducted to assess the sensor\u0026rsquo;s ability to resolve discrete amplitude changes. Operating under a fixed excitation frequency of 1000 Hz, the shaker alternated between 5-second intervals of 50 dB excitation and quiescent phases, repeated three times to confirm consistency. Following this, the amplitude was increased by 10 dB increments every 5 seconds until reaching 100 dB. The output voltage traces in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(b) exhibit a highly predictable and linear relationship between excitation amplitude and sensor response, with no evidence of compression or nonlinearity throughout the tested range.\u003c/p\u003e\u003cp\u003eImportantly, this phase of the experiment revealed that the TVS maintained consistent signal fidelity across multiple excitation cycles and amplitude levels, reinforcing its suitability for applications where stable and repeatable measurements are critical \u003csup\u003e\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e. The sensor\u0026rsquo;s performance in this context suggests that it is not only sensitive to subtle variations in mechanical excitation but also robust against transient perturbations that might otherwise compromise measurement accuracy \u003csup\u003e46 45\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eFurthermore, the reproducibility of the response under repeated load cycles indicates a high degree of mechanical durability in the sensor assembly, a characteristic essential for practical deployment in industrial monitoring environments where sustained vibration exposure is expected.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Density-Dependent Vibration Attenuation Characterization\u003c/h2\u003e\u003cp\u003eFollowing confirmation of the sensor\u0026rsquo;s baseline performance, the study advanced to the characterization of vibration attenuation as a function of specimen density. For this purpose, three cubic specimens measuring 40 mm per side were fabricated using metal additive manufacturing, with nominal target densities of 10%, 60%, and 100%. The controlled variation of density was achieved by introducing internal lattice geometries of differing volume fractions while maintaining identical external dimensions, thus isolating the effect of density on mechanical damping behavior.\u003c/p\u003e\u003cp\u003eDuring experimentation, each specimen was rigidly mounted to the shaker platform, and a series of excitation frequencies were applied to identify regimes in which density-dependent attenuation became prominent. Laser displacement measurements were conducted in parallel to TVS readings, providing an independent validation dataset against which the sensor\u0026rsquo;s performance could be benchmarked.\u003c/p\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(a) through 5(f) present representative displacement time series collected from the shaker and the fully dense specimen across excitation frequencies ranging from 10 Hz to 1000 Hz. In the lower frequency bands (10\u0026ndash;50 Hz), minimal divergence was observed between the shaker\u0026rsquo;s output and the specimen\u0026rsquo;s transmitted vibration, indicating that inertial mass and internal damping effects were insufficient to produce measurable attenuation at these frequencies. However, at 100 Hz (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(d)), the displacement amplitude of the 100% density specimen decreased markedly compared to the shaker reference. This pronounced attenuation is attributed to the increased mass and internal frictional dissipation within the fully dense lattice, which act synergistically to reduce the transmitted vibrational energy.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe identification of this attenuation threshold was a critical outcome of the study, as it established an empirical basis for selecting excitation parameters likely to produce quantifiable differences among specimens of varying densities \u003csup\u003e\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e. Prior studies have demonstrated similar attenuation phenomena in metal lattice structures subjected to harmonic excitation, suggesting that the results obtained here are consistent with established mechanical behavior.\u003c/p\u003e\u003cp\u003eBuilding upon this observation, a more focused investigation was conducted to quantify the degree of attenuation under excitation frequencies of 100 Hz and 200 Hz, combined with displacement amplitudes of 25 \u0026micro;m and 50 \u0026micro;m. The displacement data consolidated in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e reveal that while all configurations exhibited some degree of attenuation relative to the shaker baseline, the 200 Hz, 50 \u0026micro;m condition provided the most pronounced differentiation among the specimens. Under this regime, the shaker maintained a stable displacement amplitude of 50 \u0026micro;m, while the 10% density specimen displayed an attenuated amplitude of 30 \u0026micro;m, the 60% specimen 26 \u0026micro;m, and the 100% specimen further reduced to 17 \u0026micro;m.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThis clear inverse relationship between specimen density and transmitted displacement amplitude demonstrates the feasibility of using vibration-based measurements as a non-destructive method for estimating internal density in additively manufactured metal components. The attenuation is understood to arise from a combination of increased stiffness, higher effective mass, and enhanced internal friction within the denser structures, all of which contribute to greater energy dissipation during dynamic loading.\u003c/p\u003e\u003cp\u003eMoreover, the strong consistency of the measured attenuation across repeated trials highlights the reliability of the test protocol and the reproducibility of the results. This robustness is critical if the method is to be adopted for routine quality control in industrial manufacturing environments.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Validation of TVS-Based Density Estimation\u003c/h2\u003e\u003cp\u003eThe final phase of the study involved assessing whether the TVS could replicate the discrimination capability of the laser displacement sensor under identical excitation conditions. The sensor was mounted atop each specimen in turn, and its output voltage was recorded during controlled vibration at the same frequencies and amplitudes previously used for displacement measurements.\u003c/p\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(a) displays representative voltage waveforms obtained from the TVS across all specimens. Consistent with the displacement data, the triboelectric output amplitude decreased proportionally as specimen density increased, indicating that the sensor successfully transduced the density-dependent attenuation into electrical signals. This observation is particularly significant, as it demonstrates that the TVS is sensitive not only to gross vibration magnitude but also to subtle variations induced by changes in specimen mass and stiffness.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe comparative analysis presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(b) plots the peak-to-peak TVS output voltage against the corresponding displacement amplitudes measured by the laser sensor. Regression analysis yielded a coefficient of determination (R\u0026sup2;) of 0.88979, confirming that the TVS output exhibits a strong linear correlation with actual mechanical displacement. This high degree of correlation validates the sensor\u0026rsquo;s capability to function as a surrogate measurement device for estimating specimen density in a non-destructive manner.\u003c/p\u003e\u003cp\u003eAlthough the absolute displacement resolution of the TVS is lower than that of the laser displacement sensor, its substantial advantages in terms of cost-effectiveness, mechanical simplicity, and self-powered operation render it an attractive option for practical deployment. The device\u0026rsquo;s reliance on triboelectric charge generation obviates the need for external power supplies or signal conditioning circuitry, reducing system complexity and maintenance requirements \u003csup\u003e\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eFurthermore, the fabrication methodology, based primarily on electrospinning and thin-film deposition, is readily scalable and adaptable to a variety of substrate materials and geometries. This manufacturing flexibility enhances the potential for widespread adoption of the TVS in diverse industrial sectors \u003csup\u003e\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e,\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eImportantly, the sensor\u0026rsquo;s performance in these experiments suggests that triboelectric mechanisms can be harnessed not only for energy harvesting but also for advanced sensing applications that traditionally rely on more complex transducers \u003csup\u003e\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u003c/sup\u003e. This dual functionality aligns with the emerging paradigm of multifunctional nanogenerator systems capable of serving both as power sources and as self-powered sensor platforms.\u003c/p\u003e\u003cp\u003eFuture work will focus on further refining the sensitivity and resolution of the TVS through optimization of material composition, surface microstructure, and electrode configuration. Additionally, efforts will be directed toward integrating the sensor into automated inspection workflows for real-time monitoring of additive manufacturing processes. The potential to combine triboelectric sensing with machine learning algorithms for predictive quality assessment represents a particularly promising avenue of research.\u003c/p\u003e\u003cp\u003eCollectively, these findings demonstrate that the triboelectric vibration sensor developed in this study offers a viable and innovative approach to non-destructive density estimation of metal 3D-printed components, with broader implications for sustainable manufacturing practices and the evolution of smart, self-powered sensing technologies.\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eIn this study, a self-powered triboelectric vibration sensor (TVS) based on the contact\u0026ndash;separation mechanism was developed and demonstrated as a novel approach for non-destructive density estimation of metal 3D-printed specimens. The device architecture employed a glass substrate supporting aluminum and electrospun PVDF-TrFE nanofiber layers, enabling effective triboelectric charge generation without any external power supply.\u003c/p\u003e\u003cp\u003eThrough systematic experiments involving vibration excitation across specimens with distinct densities (10%, 60%, and 100%), the TVS was shown to produce output voltages exhibiting a strong linear correlation with specimen density. Under the 200 Hz, 50 \u0026micro;m excitation condition, the sensor output demonstrated clear separation among the three densities, achieving a coefficient of determination (R\u0026sup2;) of 0.984, thereby validating its capacity for quantitative estimation.\u003c/p\u003e\u003cp\u003eThese results highlight the potential of triboelectric sensors to evolve beyond their traditional role as energy harvesters or simple motion detectors, demonstrating feasibility as material property estimation tools capable of providing meaningful feedback about internal structural characteristics.\u003c/p\u003e\u003cp\u003eImportantly, the TVS developed here embodies several attributes\u0026mdash;simplicity, lightweight construction, low production cost, and complete energy autonomy\u0026mdash;that position it as a promising alternative or complementary technology to existing non-destructive evaluation systems, which are often costly and complex. This versatility suggests strong potential for integration not only in additive manufacturing quality assurance but also in broader applications such as structural health monitoring, industrial machinery maintenance, and distributed sensing networks.\u003c/p\u003e\u003cp\u003eMost critically, the advancement of triboelectric nanogenerator (TENG) technology toward widespread commercialization and real-world adoption requires compelling examples of practical, value-adding applications. The TVS presented in this work serves as a representative case demonstrating that triboelectric mechanisms can be harnessed to create viable sensor platforms, bridging the gap between laboratory research and industry-ready solutions.\u003c/p\u003e\u003cp\u003eBy contributing to improved manufacturing efficiency, cost reduction, and enhanced confidence in sensor reliability, this approach offers a tangible pathway for TENG-based devices to achieve broader deployment and to become embedded in daily life as practical, sustainable technologies.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003ea. Funding\u003c/p\u003e\n\u003cp\u003eThis research was supported by the Ministry of Trade, Industry and Energy of Korea through the project “Development of 3D Printing Digital Transformation Platform Technology Based on Process Metadata” (KM250130), and by the Korea Institute of Industrial Technology (KITECH) through its in-house research project “AI-Based Real-Time Digital Transformation and Process Optimization of AM Operations” (UR250009).\u003c/p\u003e\n\u003cp\u003eb. Conflicts of interest/Competing interests\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003ec. Authors' contributions\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eYoung Won Kim\u003c/strong\u003e contributed by proposing the original idea of the study and leading the overall experimental process, from designing and conducting the tests to analyzing the data, while also taking primary responsibility for drafting and structuring the manuscript to ensure that the research objectives were clearly conveyed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eJiyong Park\u003c/strong\u003e contributed by refining the logical flow of the manuscript and planning the experimental approach based on prior references, actively engaging in the experimental validation, and focusing on reviewing and revising the paper to guarantee both scientific accuracy and overall coherence.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eDresselhaus, M. S. \u0026amp; Thomas, I. 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The developed TVS employed a rigid glass substrate combined with an aluminum friction electrode and an electrospun PVDF-TrFE nanofiber layer, which together established a contact-separation-based triboelectric conversion mechanism. The nanofiber layer, characterized by its high porosity and flexibility, was engineered to increase the effective contact area and enhance the sensing sensitivity, while also functioning as a structural cushion to improve mechanical durability.\u003c/p\u003e\u003cp\u003eUsing this sensor, the vibration attenuation characteristics of metal 3D-printed specimens with different densities (10%, 60%, and 100%) were measured. Under test conditions of 200 Hz frequency and 50 \u0026micro;m amplitude, the results demonstrated a clear linear correlation between the specimen density and the degree of vibration attenuation. The relationship between the TVS output voltage and specimen density was quantified with a coefficient of determination (R\u0026sup2;) of 0.984, confirming the feasibility of accurate density estimation.\u003c/p\u003e\u003cp\u003eThese findings indicate that the triboelectric sensor can be extended beyond conventional energy harvesting applications into a practical sensing platform capable of industrial use in structural health monitoring and quality assessment of 3D-printed components. Furthermore, this study provides a concrete example of how TENG technology can contribute to broader commercialization and adoption by demonstrating low-cost, battery-free, and lightweight advantages that enable deployment across diverse industrial settings.\u003c/p\u003e","manuscriptTitle":"Self-Powered Triboelectric Vibration Sensor for Non-Destructive Density Evaluation of Metal 3D-Printed Parts","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-01 07:57:19","doi":"10.21203/rs.3.rs-7521617/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major Revisions Needed","date":"2025-11-16T09:17:13+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2025-09-22T01:43:33+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-20T16:32:16+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-11T05:54:44+00:00","index":"","fulltext":""},{"type":"submitted","content":"The International Journal of Advanced Manufacturing Technology","date":"2025-09-08T01:48:02+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"the-international-journal-of-advanced-manufacturing-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jamt","sideBox":"Learn more about [The International Journal of Advanced Manufacturing Technology](https://www.springer.com/journal/170)","snPcode":"170","submissionUrl":"https://submission.nature.com/new-submission/170/3","title":"The International Journal of Advanced Manufacturing Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"a8af7415-b042-467e-944f-4abdd973872f","owner":[],"postedDate":"October 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2025-11-16T14:17:38+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-01 07:57:19","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7521617","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7521617","identity":"rs-7521617","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}