Intelligent Characterization of the SACE Process Using Time Series Classification
The International Journal of Advanced Manufacturing |
A Multitasking Environment for Real-Time Monitoring of Discharging Activity During SACE
IEE International Conference (INDUSCON) |
Applications, Materials, and Fabrication of Micro Glass Parts and Devices
Materials Today |
Lab Publications
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Seyedi Sahebari, Seyed Mahmoud, et al. "Intelligent characterization of spark-assisted chemical engraving (SACE) process using time series classification." The International Journal of Advanced Manufacturing Technology 130.1 (2024): 945-960.
Spark-Assisted Chemical Engraving (SACE) requires precise control over key factors to overcome gas film instability and achieve reproducible optimal resolution and machining speed. This paper presents a substantial advancement in the SACE micromanufacturing technique by introducing a composite algorithm. This algorithm leverages deep learning and time series classification for sequence-to-sequence intelligent classification. Two distinct architectures, the Temporal Convolutional Network (TCN) and Long Short-Term Memory (LSTM), were subjected to evaluation. They were trained and optimized using Bayesian optimization, resulting in impressive accuracies of 97.18% for TCN and 96.44% for LSTM. The algorithm relies on TCN due to its superior performance for classifying current data points and subsequently computing derived parameters like gas film formation time, lifetime, mean discharge current and energy. Its versatility is demonstrated across various experimental conditions, showcasing its potential for rapid and accurate systematic studies. By highlighting the algorithm’s applicability in real-time process control for SACE, this study establishes a foundation for future advancements in the field of glass micromanufacturing. Eldiasty, Marwan S. Investigation of signal shape effects on the gas film in spark-assisted chemical engraving. Diss. 2023. Spark-Assisted Chemical Engraving (SACE) is a promising method for machining glass micro-parts and devices. However, intricate control requirements linked to the gas film surrounding the tool present a significant challenge in SACE. While several studies have explored the influence of SACE parameters on the gas film, there exists a literature gap regarding the impact of voltage signal shapes on this film. The thesis fills this void by investigating diverse voltage signal shapes designed to enhance the gas film stability. A robust methodology was established linking gas film properties to investigate the effects of signal shapes on the gas film. The research applied these findings to machining applications, establishing correlations between signal shapes and machining outcomes. Key contributions include a refined methodology for gas film evaluation, advancements in understanding signal shapes’ impact on the process, identification of optimal parameters, and potential improvements in machining through a custom signal shape design. Bassyouni, Zahraa Hassan. The design and development of a Spark Assisted Chemical Engraving system with force feedback control. Diss. 2023. Spark Assisted Chemical Engraving is a hybrid micromachining method capable of machining micro-holes and micro-channels on non-conductive substrates. This thesis centers around the design of a mechatronics system for precision manufacturing using SACE technology. The setup consists of a machining head and a processing cell. The electronics of the system are implemented on printed circuit boards and embodied in a well-ventilated box that connects the different components of the system. A current probe adapter that enables the reading of the current signal is designed. The system is modeled and controlled, and a force sensor that can detect machining forces is developed. A force-feedback drilling technique is implemented, where the machining continues with minimal contact forces (less than 200 mN). A preliminary study on characterizing the surface quality of machined holes was conducted, and a model that can characterize the surface texture of machined holes is developed. Hamed, Hazem Fawzi. Electroforming of personalized miniature metal parts using additively manufactured molds. Diss. 2023. In response to evolving manufacturing trends favoring personalized, small-batch production, this thesis centers on the development of additively manufactured molds to facilitate the electroforming of personalized metal parts. The methodology encompasses standardized mold design, experimental procedures for mold development and electroforming, and a simulation model for visualizing and predicting the deposition process. The study provides critical design considerations and guidelines for electroforming within additively manufactured molds, successfully demonstrating the production of composite metal components in 2.5D and 3D configurations. Emphasizing cost efficiency and improved part quality, especially for limited-thickness metal components, the developed technique presents advantages over available metal additive manufacturing processes. Electroforming emerges as a versatile and robust metal additive manufacturing technique, expanding its application beyond traditional limitations of thin-walled hollow structures, 2D components and applications at the nanoscale. Sahebari, Seyed Mahmoud Seyedi, Ahmad Barari, and Jana D. Abou Ziki. "A Multitasking Environment for Real-Time Monitoring of Discharging Activity During SACE Process Using LSTM." 2023 15th IEEE International Conference on Industry Applications (INDUSCON). IEEE, 2023. Real-time control of SACE gas film stability is crucial, as it significantly impacts micromachining repeatability and quality in this technology. Gas film stability and discharging activity are interconnected, and monitoring real-time parameters like mean discharge current and energy, which serve as indicators of gas film stability, is the first step in this effort. An intelligent algorithm deployed on a dSPACE platform uses LSTM for online discharge activity monitoring, identifying discharges and calculating indicators. Maintaining a short enough sampling time for prompt discharge detection presents overrun errors. Therefore, a real-time multitasking environment with a 1.6e-5 seconds sample time is executed. A more complex LSTM enhances detection accuracy but ex-tends execution time, potentially resulting in more unprocessed data loss. The research examines the real-time model with various algorithm feed batch sizes and LSTM complexities, particularly the number of hidden units. An example of a 2-hidden-unit LSTM demonstrates promising 90.45% accuracy, processing data every 264 milliseconds with a 131-millisecond batch (approximately 0.5 processing ratio), indicating superior performance. In the future, exploring LSTM hyperparameter optimization and real-time model parameter tuning is recommended to enhance accuracy and processing ratio. Hamed, Hazem, et al. "Applications, materials, and fabrication of micro glass parts and devices: An overview." Materials Today (2023). Material selection is a critical factor that affects the performance of devices and parts on a microscale. Glass is a candidate material for micro applications as it possesses notable characteristics like biocompatibility, optical transparency, mechanical rigidity, and thermal stability, to name a few. Glass-based micro parts and devices have been developed to accommodate various applications in various fields. The fields mentioned in this review article include medical, optics, metrology, microelectronics, micro-mechanisms, and microfluidics. The most significant parts and devices in each field are investigated in terms of their application, function, fabrication process and glass significance. In addition, an overview of glass materials and fabrication techniques on a micro-scale is further discussed. The review aims to shed light on the capabilities of glass as a material that has substantial potential to enhance the performance of micro parts/devices and clarify the associated challenges. Further advancements in micro-machining technologies could address one of the primary issues facing micro-glass applications in the future. Bassyouni, Zahraa, Anis Allagui, and Jana D. Abou Ziki. "Microsized electrochemical energy storage devices and their fabrication techniques for portable applications." Advanced Materials Technologies 8.1 (2023): 2200459. Over the last decade, Lab-on-chip (LOC) technology has been thriving to support the ever-increasing demand of high-throughput, fast, accurate, and reliable analysis in an extensive variety of miniaturized systems for medical, chemical, and biological applications. Furthermore, portable electronics and consumer devices such as cell phones, tablets, smart watches, point-of-care devices, wireless sensor nodes, radio frequency identification, and other gadgets have witnessed a tremendous demand worldwide. These fast-paced technologies have an intimate correlation with the booming research activity in micro-supercapacitors (MSCs) and microbatteries (MBs); two energy storage devices which have claimed the lion's share in powering LOC components and other portable devices. In this review, MSCs and MBs are presented with highlights on their main components, structure, and types, as well as their state-of-the-art performance capabilities. The recent efforts in fabrication strategies, mainly those compatible with device fabrication techniques, stating the advantages and limitations of each are also reviewed. The paper also emphasizes the need for a benchmarking standard upon which performance is compared, as scholarly work shows a discrepancy in the use of different performance metrics to describe the electrochemical performance of such devices. Trendov, Veronica, et al. "A mechanism to detect lateral forces during Spark assisted chemical engraving microcutting." (2022). Spark Assisted Chemical Engraving (SACE) is a non-traditional micro-machining technology, with one of its unique characteristics being the physical distance relationship between the tool and workpiece during machining. Previous papers have illustrated that maintaining space between the tool and workpiece during machining is beneficial for high quality results; in this paper, for the first time, methods of detecting very small lateral forces experienced on the workpiece from the tool head will be examined on the design level. Using compliant mechanisms to ensure stability of the workpiece during machining while being capable of transferring affected forces to sensors via amplification mechanisms is the proposed approach of this paper to facilitate machining with minimal tool-workpiece contact. Four workpiece holding flexure designs with three compliant hinge variants were analyzed for their maximum deflection under lateral load, with one design being developed further with the modification to account for axial force loads during machining. This further developed design was tested in simulations with the amplification mechanism attached in order to determine the efficiency of force magnification. The goal was to detect a small amount of lateral force and have the flexure mechanism deflect minimally; the developed flexure experienced a typically small lateral force, which caused a minimal deflection in the fixture and a sizable deflection in the amplification mechanism. From these simulation results, is it determined that the design developed has achieved the set out criteria for allowing less than 5 microns of deflection with a 20 mN lateral load. Sahebari, Seyed Mahmoud Seyedi, Ahmad Barari, and Jana D. Abou Ziki. "Neural network signal processing in spark assisted chemical engraving (SACE) micromachining." 2021 14th IEEE International conference on industry applications (INDUSCON). IEEE, 2021. Spark Assisted Chemical Engraving (SACE) is an emerging micromanufacturing technology of mainly non-conductive materials like glass and ceramic. The micromachining happens due to high temperature etching in electrolytic solution by electrochemical discharges which are generated through a tool-electrode across a gas film surrounding it. The gas film shall be present so that discharges, which are the heat source, can be generated hence causing local machining of the substrate. Studies have shown that the gas film breaks and reforms every few milliseconds depending on several factors, some of which are not known or are unclearly understood. Investigation of the gas film formation, its characteristics and the factors that affect its stability could lead to enhancing the SACE machining performance. In this work an algorithm based on Artificial Neural Networks (ANN) is developed to accurately estimate the gas film formation time. The method shown is a comprehensive one that can be applied to various machining conditions of the SACE process. To our best knowledge, few attempts have been done in the field of SACE signal processing and this work is the first study where ANN is used for gas film parameters calculation. Bassyouni, Zahraa, and Jana D. Abou Ziki. "The capabilities of spark-assisted chemical engraving: a review." Journal of Manufacturing and Materials Processing 4.4 (2020): 99. Brittle non-conductive materials, like glass and ceramics, are becoming ever more significant with the rising demand for fabricating micro-devices with special micro-features. Spark-Assisted Chemical Engraving (SACE), a novel micromachining technology, has offered good machining capabilities for glass and ceramic materials in basic machining operations like drilling, milling, cutting, die sinking, and others. This paper presents a review about SACE technology. It highlights the process fundamentals of operation and the key machining parameters that control it which are mainly related to the electrolyte, tool-electrode, and machining voltage. It provides information about the gas film that forms around the tool during the process and the parameters that enhance its stability, which play a key role in enhancing the machining outcome. This work also presents the capabilities and limitations of SACE through comparing it with other existing micro-drilling and micromachining technologies. Information was collected regarding micro-channel machining capabilities for SACE and other techniques that fall under four major glass micromachining categories—mainly thermal, chemical, mechanical, and hybrid. Based on this, a figure that presents the capabilities of such technologies from the perspective of the machining speed (lateral) and resulting micro-channel geometry (aspect ratio) was plotted. For both drilling and micro-channel machining, SACE showed to be a promising technique compared to others as it requires relatively cheap set-up, results in high aspect ratio structures (above 10), and takes a relatively short machining time. This technique shows its suitability for rapid prototyping of glass micro-parts and devices. The paper also addresses the topic of surface functionalization, specifically the surface texturing done during SACE and other glass micromachining technologies. Through tuning machining parameters, like the electrolyte viscosity, tool–substrate gap, tool travel speed, and machining voltage, SACE shows a promising and unique potential in controlling the surface properties and surface texture while machining. |
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