M. SLAMANI Mohamed

Precision machining of turbine blade cooling channels presents significant challenges in aerospace manufacturing, where micron-level accuracy directly impacts engine performance. This research develops an intelligent fixture optimization system integrating genetic algorithms (GA) with Plücker coordinate mathematics to achieve optimal locator configurations. The methodology maximizes the determinant of the Plückerian location matrix, establishing a stability-optimized reference frame at the blade root while maintaining compatibility with industrial machining processes.
Experimental validation on complex turbine airfoil geometries demonstrates a 32 % improvement in positional accuracy (reducing errors from 0.25 mm to 0.17 mm) compared to conventional fixturing methods, verified through coordinate measuring machine (CMM) inspection and destructive cross-section analysis. The optimized design addresses critical production requirements including: (1) enhanced operator visibility for contact verification, (2) improved gauge shim compatibility, and (3) maintained thermal stability during electrochemical drilling operations.
This work provides manufacturers with a computationally efficient framework that significantly reduces fixture development time while achieving aerospace-grade precision. The demonstrated success on turbine blade geometries suggests immediate applicability for aeroengine components and adaptability to other complex machining applications in the energy sector.

Drilling composite materials is a critical stage in assembly, especially for structures that rely on mechanical fasteners. This research investigates the drilling of a hybrid composite made of an epoxy matrix reinforced with natural jute and Alfa fibers, focusing on three key cutting parameters: feed rate, spindle speed, and drill point angle. The study aims to assess how these factors affect thrust force, delamination, and the quality of the hole’s exit. Findings indicate that using a low feed rate, moderate spindle speed, and a smaller drill point angle helps reduce delamination and enhances hole surface finish. On the other hand, higher feed rates increase thrust force, raising the likelihood of damage and defects. The optimal conditions for minimizing thrust force and delamination while maintaining good hole quality involve a drill with a 110° point angle, a spindle speed of 1000 rpm, and low feed rates. Under these settings, thrust force remains low—ranging from 32.38 N at 50 mm/min to 26.07 N at 150 mm/min—while the delamination factor stays minimal, peaking at 1.052 even at higher feed rates. These findings emphasize the significance of carefully choosing cutting parameters to maintain composite integrity and enhance drilling efficiency. The study highlights the need to balance productivity with precision, optimizing cutting conditions to reduce damage and ensure the structural reliability of hybrid composites.

Optimizing drilling parameters for composite materials is challenging due to their anisotropic and heterogeneous properties, which often cause defects like delamination and poor surface finish. This study employs the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) to optimize drilling parameters, balancing cutting force, temperature, surface roughness, and delamination. Experimental data from 48 drilling trials, using three drill types (solid carbide, HSS, and composite-specific) with varied spindle speeds and feed rates, were analyzed. TOPSIS ranked parameter combinations, identifying Drill 2 (solid carbide) at 1000 rpm and 50 mm/min as optimal, achieving minimal delamination and superior surface finish.
This approach enhances manufacturing precision, reduces material waste, and promotes sustainable machining. The findings offer practical insights for industries like aerospace and automotive, improving product quality and process efficiency.
Keywords: TOPSIS, Composite Drilling Optimization, Sustainable Machining, Multi-Criteria Decision-Making, Process Efficiency

Although CNC machines offer numerous advantages, machining hybrid composites presents unique challenges, particularly in the proper positioning and securing of tensile specimens during the process. These materials, often comprising layers of different types, can behave unpredictably under cutting forces, complicating the task of achieving precise, standard-compliant shapes. This study introduces a specialized machining fixture developed to securely hold and manipulate tensile specimens for composite testing, meeting the stringent requirements of academic research where dimensional precision is paramount. The fixture's design features robust clamping mechanisms that stabilize various specimen geometries, ensuring minimal distortion and precise alignment during CNC machining. The fabrication process included careful material selection and the application of advanced machining techniques to achieve exceptional dimensional accuracy. Performance evaluation through machining trials assessed factors such as clamping force, stability, and usability. Results demonstrate that the proposed fixture significantly enhances machining efficiency and accuracy, thereby improving the reliability of composite material testing.
Keywords: CNC precision machining; tensile specimen preparation; hybrid composite materials; International standards (ISO, ASTM).

In this study, the evaluation of 75 holes drilled in a hybrid bio-composite jute/palm/polyester plate and controlled by a coordinate measuring machine (CMM) is essential to ensure the quality, dimensional precision, and geometric conformity of the plate. This rigorous process is necessary to meet industrial standards for circularity and cylindricity, which are essential criteria for high-performance applications. Additionally, the integration of artificial neural network (ANN) techniques has revolutionized this approach by enabling precise predictions of key parameters such as delamination, circularity, and cylindricity. In this study, the ANN was trained with 52 samples (70%), while 8 samples (10%) were used for validation and 15 others (20%) for testing at different stages. The results show the influence of feed rate on the delamination factor (Fd) (R2 = 0.98), circularity error (R2 = 0.99), and cylindricity error (R2 = 0.98). This predictive approach significantly improves the reliability and efficiency of the evaluation process

This review paper explores the latest advancements and optimization strategies in fixture layout design and machining processes, particularly within the framework of Industry 4.0. It begins with a detailed analysis of fixture layout design and its impact on machining precision and efficiency. The paper reviews various optimization methods for fixture layouts, including traditional approaches and emerging techniques enabled by advanced technologies. It further examines the evolution of machining processes and the integration of automation and robotics in modern manufacturing environments. The review highlights the significance of intelligent fixtures and robot-based systems in enhancing flexibility, precision, and overall performance. By synthesizing current research and practical applications, this paper provides insights into future trends and developments in fixture and machining process optimization.
Keywords Fixture layout optimization · Industry 4.0 · Robot-based fixtures · Machining process efficiency · Intelligent manufacturing systems

L’ingénierie inverse est essentielle pour analyser et valider les tolérances géométriques des formes complexes. Cette étude met en œuvre un processus de rétro-conception avec Geomagic Design X, un logiciel spécialisé dans la conversion de scans 3D en modèles numériques précis via la technologie laser. Une pièce complexe a été scannée en 3D, générant un modèle maillé, ensuite converti en modèle solide pour une fabrication de haute précision. Les écarts entre le maillage, le modèle solide et les tolérances spécifiées ont été rigoureusement analysés. Les résultats montrent que l’intégration de la modélisation de surface et de la conception solide, grâce aux outils d’ingénierie inverse, optimise la gestion des tolérances des formes complexes, assurant une précision accrue. Cette approche démontre l’efficacité de la rétro-conception pour répondre aux exigences de fabrication modernes.
Mots clés : L'ingénierie inverse, tolérances géométriques, rétro-conception, scan 3D, l'émission du laser, formes complexes.

Hybrid composites reinforced with palm and jute fibers are increasingly valued in modern manufacturing due to their exceptional strength-to-weight ratio and eco-friendly properties. This study examines the drilling process of these hybrid composites, with a focus on circularity and cylindricity errors as key indicators of hole quality. The composite material was composed of 15 % palm fibers and 15 % jute fibers by weight. A distinguishing feature of this research is the innovative use of bootstrap analysis to quantify uncertainty in predicting circularity and cylindricity errors. The investigation explored the effects of spindle speed and feed rate on machining outcomes, uncovering intricate interdependencies between these parameters. Results show that lower spindle speeds yield more precise and consistent hole quality, while higher speeds increase variability. Two regression models were developed to predict circularity and cylindricity errors, demonstrating strong predictive accuracy with R-squared values of 0.91 and 0.95, respectively. The application of bootstrap analysis further validated the robustness of these models by providing detailed uncertainty estimates across a range of cutting conditions. Machining conditions associated with minimal errors were determined at a spindle speed of 1592 rpm and a feed rate ranging from 0.08 mm/rev to 0.12 mm/rev, yielding circularity errors as low as 44 µm and cylindricity errors of 59 µm.

The purpose of this study is to explore drilling defects in hybrid jute/palm fiber composites and propose practical solutions for enhancing machining outcomes. This work is novel in its detailed analysis of delamination, fiber pull-out, and surface fluffing using HSS drills. The results reveal significant differences in delamination factors between the entrance (jute fibers) and exit (palm fibers) under varying machining conditions. Quantitative analysis reveals that optimal conditions for minimizing delamination occur at a spindle speed of 2388 rpm and feed rate of 0.04 mm/rev, achieving delamination factors of 1.121 (entrance) and 1.069 (exit). These findings emphasize the critical role of machining parameters in controlling drilling defects and improving the integrity of hybrid composite materials. Using Response Surface Methodology, predictive models identified feed rate as the dominant factor. Optimizing resin application improved structural integrity and reduced defects, offering experimental evidence for industrial applications in sustainable hybrid composite manufacturing.
Keywords: Hybrid composites, drilling defects, delamination, entrance defects, exit defects,, Response Surface Methodology (RSM)

This study investigates the impact of cutting parameters on the accuracy of robotic trimming of Carbon Fibre Reinforced Polymers (CFRPs). The research focuses on analyzing cutting forces and their influence on part quality during the trimming process. Experiments were conducted using a six-axis industrial robot equipped with a high-speed spindle, with cutting forces measured in the x, y, and z directions. Results indicate that higher cutting speeds and feed lead to increased cutting forces, which in turn leads to elevated inaccuracies in the parts being machined. The study emphasizes the importance of understanding cutting force behavior for optimizing machining parameters and improving part quality. Findings suggest the need for advanced control strategies to mitigate dynamic errors and enhance machining accuracy in CFRP trimming applications.

In the manufacturing of composite materials, achieving high precision in drilling processes is crucial to ensure product quality and performance. This study investigates the influence of drilling parameters on key performance metrics delamination, circularity, and cylindricity using the Taguchi method. An L25 orthogonal array was employed to systematically explore the effects of spindle speed, feed, and drill type on the quality of drilled holes. The analysis of variance (ANOVA) revealed that feed significantly influences the outcomes across all drill materials, with cutting speed playing a secondary role. The study further applied desirability function analysis (DFA) to optimize these multi-responses, identifying the optimal parameter settings for each drill type. The results highlight the critical role of feed in minimizing delamination, circularity, and cylindricity with the optimal settings offering significant improvements in drilling performance.

Dans l'industrie manufacturière, il existe plusieurs types de pièces de formes complexes possédant diverses fonctions. Les aubes de turbine sont l'un des composants les plus importants des turbines à gaz. Cependant, ces aubes ont des formes complexes et une courbure de surface irrégulière qui les rendent difficiles à usiner. La production de ce type de pièces est si compliquée et nécessite un contrôle élevé du processus d'usinage, une programmation CNC avancée, des outils innovants et des montages spéciaux permettant de maintenir exactement et de manière rigide dans une position unique de la pièce pendant l'usinage. Comme les besoins de précision de plus en plus augmentent dans l'industrie, de nouvelles configurations et procédés de fabrication des ailettes de turbines à gaz, doivent être développés pour satisfaire les exigences de la production moderne.
La présente invention concerne le domaine de fabrication industrielle tel que, l’aéronautique, l’énergie, et la défense, précisément, dans le domaine de fabrication des pièces à haute précision telles que les aubes de turbines à gaz.
Donc l’objectif de cette invention est de donner une contribution dans le domaine de la fabrication et l’usinage des ailettes de turbines sur des machines-outils à commande numérique par le développement d’un dispositif d’usinage permettant de maintenir les pièces dans une position unique d’une manière répétitive et rigide pendant l’usinage.
Ce dispositif contribue, de manière significative, à l’amélioration de la productivité des ailettes de turbines, en matière de qualité et de temps d’exécution réduit.

The industry is increasingly drawn to biocomposites, largely due to the growing interest in natural fiber-reinforced composites (NFRCs). These materials offer significant advantages, including cost efficiency, biodegradability, environmental sustainability, and desirable mechanical properties. Consequently, the manufacturing of natural fiber-reinforced polymer (NFRP) composites has gained attention from both industry professionals and researchers. The adoption of these eco-friendly materials in sectors such as automotive and aerospace has further fueled interest in understanding their production methods. However, machining NFRP composites presents considerable challenges due to the intricate structure of natural fibers, requiring in-depth studies to address these complexities. This study provides a detailed investigation into surface roughness during the milling of Alfa/epoxy biocomposites. A total of 100 experimental trials were conducted to evaluate surface roughness, and analysis of variance (ANOVA) was employed to examine the influence of cutting parameters and chemical treatment on surface quality.

This study presents a method for modelling, predicting, and evaluating the impact of drill materials on the drilling process of hybrid palm/jute polyester composites, with the aim of enhancing hole quality regarding delamination, circularity, and cylindricity. Three drill materials, including High-Speed Steel (HSS), 5 % Cobalt-coated High-Speed Steel (HSS-Co5), and Solid Carbide drills were tested, and their impacts on drilling performance were assessed. Through thorough experimentation and statistical analysis, significant differences in results were observed between HSS drills and both HSS-Co5 and Solid Carbide drills. However, the variation in results between HSS-Co5 and Solid Carbide drill results was minimal. Additionally, the findings highlight notable disparities among drill types concerning uncertainty. The results also indicate that feed rate, drill material, and their interaction play crucial roles in determining drilling efficiency. Specifically, HSS drills consistently outperformed HSS-Co5 and Solid carbide drills, demonstrating superior performance in minimizing delamination, improving circularity, and enhancing cylindricity along with lower uncertainty.

This study presents a detailed analysis of the milling behavior of untreated and NaOH-treated composite samples at different fiber orientations (0° and 90°) using up milling and down milling techniques. A cubic regression model was employed to analyze the experimental data, demonstrating a good fit with high correlation coefficients of 0.90 and 0.91 for up milling at 0° and down milling at 90°, respectively, in untreated samples. This strong performance was also observed in NaOH-treated samples. Although other machining modes and orientations showed slightly lower correlation coefficients, the models remained statistically valid, as confirmed by the Fisher statistic exceeding the theoretical threshold at a 5% significance level. The results indicate that feed rate is the dominant factor, exerting a significant influence on normal and axial cutting forces, whereas the effect of cutting speed appears nearly negligible. Conversely, cutting speed has a more pronounced effect on feed force than feed rate, with the interaction between cutting speed and feed rate showing the highest statistical significance.

This study introduces a novel fixture designed to meet the challenges of machining complex
geometry parts, specifically gas turbine blades with irregular surface curvatures. The fixture's design
leverages the Plückerian matrix approach to strategically place locators, ensuring the workpiece is held in
a stable and repeatable position throughout the machining process. This method addresses the critical
requirement for high accuracy in the machining of turbine blades, which directly impacts the performance
of gas turbines. The fixture was fabricated and tested using the small displacement torsor (SDT) concept
to assess its effectiveness in maintaining the precise location of the workpiece under operational
conditions. The evaluation revealed that the fixture provides superior localization repeatability, reducing
the risk of deviations and enhancing the overall quality of the finished parts. The successful
implementation of this fixture design offers a significant contribution to the field of high-precision
machining, with potential applications in sectors where the production of complex-shaped components is
essential.

In modern engineering, achieving precise tolerance levels in complex assemblies is vital for
ensuring both product quality and functionality. This study presents a comprehensive framework for
tolerance analysis that integrates the unified Jacobian–Torsor model with a simulation-based approach for
quantifying uncertainty. The unified Jacobian–Torsor model is effective in representing and propagating
geometric variations, while the simulation method strengthens the analysis by estimating variability
within specified tolerances. Through a detailed case study, the framework is shown to automatically
generate tolerance specifications while considering functional interactions and manufacturing constraints.
The results validate the accuracy and reliability of this approach, making it a powerful tool for precision
engineering in the design and assembly of intricate mechanical systems.

This paper rigorously examines drilling operations in a jute/palm fiber reinforced polyester composite (15 % palm fibers, 15 % jute fibers, 70 % polyester resin, 9 mm thickness), emphasizing factors affecting hole quality. The hole quality was characterized by assessing circularity, cylindricity, and delamination. The key findings include the identification of optimal cutting conditions, where a feed rate of 0.08 mm/rev and a spindle speed of 1592 rpm maximize circularity and cylindricity. Furthermore, a lower feed rate (0.04 mm/rev) to be optimal for minimizing delamination, circularity and cylindricity, underscoring the significance of precise adjustments. The influence of drill types is highlighted, with the High-Speed Steel twist drill emerging as the superior choice, demonstrating enhanced performance. The study also reveals the sensitivity of delamination to feed rate variations, emphasizing its primary role in material damage. Cyclical trends in circularity and cylindricity are observed, with feed rate standing out as the predominant factor affecting precision.

Uncertainty analysis is essential for estimating variability within specified tolerances, particularly in three-dimensional (3D) assembly tolerance analysis. This study introduces a novel analytical approach for assessing assembly deviations, integrating the Jacobian–Torsor model with the bootstrap technique. The Jacobian–Torsor model combines the efficiency of representing tolerances with the adaptability of the Jacobian matrix for their propagation. This computerized method, based on the unified Jacobian–Torsor approach, focuses on cam-clamping devices, specifically the fastening flange component. The novelty of this study lies in the application of the bootstrap technique, a Monte Carlo Simulation approach, for uncertainty analysis to estimate variability within specified tolerances. A comprehensive comparison of statistical methods—bootstrap, stratified sampling, Bayesian statistics, and analytical methods—demonstrates the advantages of the Bootstrap approach. The results emphasize its user-friendliness and precision, even with complex shapes. The primary aim is to highlight the utility of the unified Jacobian–Torsor method for tolerance analysis. An experiment involving the fastening flange assembly illustrates the practical application of this approach. The findings confirm the effectiveness of the proposed method, demonstrating its accuracy and reliability for cam-clamping devices in real-world assembly scenarios with intricate geometries.

Studying the drilling of a hybrid jute/palm composite material offers significant contributions to sustainable material development. Incorporating renewable jute and palm fibers represents an innovative, eco-friendly approach compared to synthetic composites. This research aims to optimize drilling parameters to reduce defects and evaluate the performance of different drilling tools, crucial for industrial applications. Drilling is performed via three different types of drills bit: High-Speed Steel, HSS-Co5 coated high-speed steel with 5% cobalt, and carbide. The drilling process involves adjusting the feed and rotational speed. Response Surface Methodology (RSM) was used to select drilling settings by validating experimentally obtained data and predicting the behavior of the structure based on cutting circumstances. The findings indicated that the most effective cutting parameters for minimizing delamination are achieved using the HSS drill bit, namely at lower feed and rotational speeds. Delamination remains below the threshold of 1.106 when the feed is 0.04 mm/rev and the rotational speed is 1592 rpm. The analysis of the results obtained using the response surface methodology indicates that the R2 coefficient for cylindricity is 0.96%. In contrast, the rate of delamination is 0.79% and the rate of circularity is 0.89%.

Flax/epoxy composites are recognized as an eco-friendly alternative to synthetic fibers in engineering. Understanding how fiber orientation affects cutting forces and surface characteristics is essential for machining these materials. This study investigates the relationship between fiber orientation and cutting forces (feed, normal, passive) as well as surface roughness in flax/epoxy composites. Results show that fiber orientation significantly impacts cutting forces. Cutting parallel to fibers (0° and 90° orientations) generally requires less force, with 0° needing higher normal force. At 0° orientation, feed force is 46.47 N, normal force is 58.86 N, and passive force is 54.44 N. At 90° orientation, feed force is 56.66 N, normal force is 44.68 N, and passive force is 50.95 N. Oblique orientations (45° and −45°) require higher forces, especially 45°, with the highest normal force of 77.95 N. Surface roughness analysis shows 90° orientation results in the lowest average roughness (Ra) of 10.97 µm but the highest surface roughness (Sa) of 34.25 µm. Conversely, 45° orientation has the highest Ra of 14.2 µm but lower Sa of 22.6 µm. Ra and Sa values for 0° orientation are 13.72 µm and 24.6 µm, and for −45° orientation, they are 12.3 µm and 21.8 µm. Correlation analysis reveals significant relationships between cutting parameters and surface quality, with higher feed rates correlating with smoother surfaces (lower Sa and Ra values). Fiber orientation also significantly influences fluffing defects, with 0° orientation minimizing these defects, while 45° and −45° orientations result in varied patterns.

This project focuses on the examination and design of a medically relevant component, specifically a dental prosthesis, using the method of reverse engineering. Reverse engineering involves a thorough analysis of an existing piece to understand its functioning and specifications, with the aim of creating an improved or adapted version. In the medical context, this approach is employed to develop a specific component with medical significance. This study explores the steps of this process, emphasizing detailed understanding, design, and
implementation of this dental prosthesis, with a particular focus on its utility and importance in the medical field

The continuous evolution of composite materials has sparked increasing interest in more precise and reproducible testing methods. The use of Computer Numerical Control (CNC) to create molds for composite material tensile specimens represents a significant advancement in this field. This innovative approach ensures enhanced precision, uniformity in sample fabrication, and efficient adaptation to the specific requirements of composite materials. This article focuses on the CNC mold creation process for composite material tensile specimens, highlighting its advantages and advancements in the field of material testing.

Purpose – This research paper aims to optimize the calibration process for an ABB IRB 120 robot, specifically for robotic orbital milling applications,
by introducing and validating the use of the observability index and telescopic ballbar for accuracy enhancement.
Design/methodology/approach – The study uses the telescopic ballbar and an observability index for the calibration of an ABB IRB 120 robot,
focusing on robotic orbital milling. Comparative simulation analysis selects the O3 index. Experimental tests, both static and dynamic, evaluate the
proposed calibration approach within the robot’s workspace.
Findings – The proposed calibration approach significantly reduces circularity errors, particularly in robotic orbital milling, showcasing effectiveness
in both static and dynamic modes at various tool center point speeds.
Research limitations/implications – The study focuses on a specific robot model and application (robotic orbital milling), limiting generalizability.
Further research could explore diverse robot models and applications.
Practical implications – The findings offer practical benefits by enhancing the accuracy of robotic systems, particularly in precision tasks like orbital
milling, providing a valuable calibration method.
Social implications – While primarily technological, improved robotic precision can have social implications, potentially influencing fields where
robotic applications are crucial, such as manufacturing and automation.
Originality/value – This study’s distinctiveness lies in advancing the accuracy and precision of industrial robots during circular motions, specifically
tailored for orbital milling applications. The innovative approach synergistically uses the observability index and telescopic ballbar to achieve these
objectives.

This paper demonstrates how the vertical straightness error and pitch and roll
deviations are coupled together for straightness error measurements. The effects of the Bryan
and angular errors on the vertical straightness error are investigated. An effective approach is
proposed in this research paper, to identify both straightness and angular errors of a prismatic
mobility of a machine tool using a dial comparator. The study includes the development of a
mathematical model that describes the relationship between straightness and angular errors,
and the construction of a matrix identification system that is capable of calculating the vertical
straightness error at the ball screw level, as well as roll, pitch, and yaw errors of a prismatic
axis. The pseudo-inverse method is used to solve the system. The advantages of this method
compared to optical measurements lie in its simplicity, its speed of measurement and
identification and its lower cost.

The field of automation in tool path generation for a 3-axis CNC machine is experiencing significant growth in the computer-aided manufacturing sector. Current research efforts are focused on improving the efficiency and precision of this process. To achieve this, new technologies are being explored to enable a more advanced and automated generation of tool paths. In this article, we will examine the current state of research concerning automated tool path generation on a 3-axis CNC machine using Matlab programming tools. As an example, we will consider a complex butterfly shape derived from a mathematical function that allows drawing the 2D geometric form. At the end of the process, a G-code is automatically generated for future use in the CNC machine. The obtained results are highly encouraging, which provides further motivation for continuing research in this direction.

The environmental effects on the response of Date Palm Fiber (DPF) composites are explored through an in-depth analysis of water absorption behavior. This study comprehensively investigates the influence of fiber content, immersion time, and water type on mass gain. Rigorous experimentation and advanced statistical analyses quantify the percent contribution of each factor, emphasizing the dominant role of fiber content at 96.61%. While immersion time and water type contribute relatively smaller percentages (2.11% and 1.28%, respectively), their insights are invaluable for tailored composite design. The study extends to interaction effects, showcasing the combined influence of factors. Regression models, progressing from linear and reciprocal formulations to comprehensive global models, are developed. Meticulous examination of prediction accuracy, using diverse statistical metrics, highlights the superior performance of the global reciprocal model across different water types. This work provides essential insights for optimizing DPF composite design, fabrication, and application, empowering engineers and researchers to make informed decisions in industries demanding tailored water absorption behavior.

This study investigates drilling-induced damage in hybrid composites, specifically examining the interplay between cutting parameters and hole delamination. Three drill types—high-speed steel (HSS), 5% cobalt-coated high-speed steel (HSS-Co5), and solid carbide—are analyzed for their distinct impacts. The research underscores the substantial influence of feed rate and rotational speed on delamination, noting that increased feed rates exacerbate the issue. Notably, HSS drills exhibit superior performance in mitigating delamination compared to other types. The study unequivocally demonstrates that operating the HSS drill at lower feed rates and rotational speeds significantly minimizes delamination, achieving remarkable results at a feed rate of 0.04 m/rev and 1592.35 rpm. While rotational speed’s consistent significance is limited, with the rotation speed 2388.53 rpm, the delamination factor of the HSS drill recorded the smallest values with all the cutting conditions of the tests carried out. These insights emphasize the critical need for optimized cutting parameters when drilling hybrid composites, providing valuable guidance for engineering applications and materials science.

Currently, there is a notable attraction within the industry towards biocomposites, driven by the increasing fascination with natural fiber-reinforced composites (NFRCs). These NFRCs offer remarkable benefits, including cost-effectiveness, biodegradability, eco-friendliness, and favorable mechanical properties. As a result, the manufacturing processes of natural fiber reinforced polymer (NFRP) composites have garnered attention from both industrial professionals and scientists. The emergence of these eco-friendly materials in the automotive and aerospace industries has sparked interest in understanding their production techniques. However, the machining processes of NFRP composites pose significant challenges due to the complex structure of natural fibers, necessitating thorough studies to address these issues effectively. This research paper presents a comprehensive investigation on surface roughness during the milling process of Alfa/epoxy biocomposites. A set of 100 experimental trials was conducted to test the surface roughness, and analysis of variance (ANOVA) was used to assess the impact of cutting parameters and chemical treatment on surface quality.

To develop a predictive model for surface roughness, a hybrid approach called ANN-GA (artificial neural networks-genetic algorithms) is proposed in this research. This approach combines ANN and GA to determine an optimal neural network architecture. The performance of the ANN-GA model is compared to the Levenberg–Marquardt backpropagation (LM) algorithm.

ANOVA results show that the feed per revolution have a significant influence on surface roughness, followed by the chemical treatment of fibers, while machining direction has a smaller effect. The ANN-GA model demonstrates good accuracy in surface roughness prediction compared to the LM algorithm.

Flax fiber-reinforced polymer composites are an interesting alternative to synthetic fiber-reinforced polymer composites
for many engineering applications. When machining flax fiber-reinforced composite materials that are by definition
heterogeneous, the matrix and the fibers react differently and hence many sorts of damage may occur such as poor surface roughness, delamination, and fluffing. The novelty of the current work lies in identifying the major factors that affect
the quality of the milled surface of composites reinforced with flax fibers and provides recommendations and collaborative solutions to the composite machining community. In this study, the impact of cutting conditions (cutting speed, feed
rate, and fiber orientation) on the cutting forces and surface roughness during milling of the flax/epoxy composite is investigated. For this purpose, slotting tests are performed on flax fiber-reinforced polymer plates using a carbide end mill tool
based on a full factorial design of experiment. Furthermore, a randomization in the order in which experimental runs are
done is used to reduce bias by balancing the effect of uncontrolled variables that have not been accounted for in the
experimental design. It is concluded that the feed rate has the most influence on the cutting forces and roughness parameters. Moreover, the fibers orientation also has a significant effect on the outputs, and the cutting speed has less effect but
it remains significant.

In the manufacturing industry, Mastercam X5 is a widely used CNC simulation
and programming suite that offers high efficiency. It can be easily integrated with the
Mastercam model, providing full associativity and seamless single-window integration. The
iMachining technology, which uses patented algorithms for specific operations, is a
breakthrough in CNC milling tool path technology. It optimizes the tool path, reduces
machining time, and minimizes tool wear. The suite enables a wide range of machining
operations on various stock objects, making it flexible and versatile. The simulation process
allows real-time observation of operations and ensures error-free G-code for physical
operation. This paper details the procedures of machining a spur gear from stock material
using Mastercam 2D iMachining technology. The simulation process generates automatic Gcodes for practical use in CNC machines. Mastercam simplifies the concept, operation, and
importance of using CAM software in modern-day manufacturing industries. It also enables
optimization of operational steps and parameter details to save time, cost, and tool lives,
improving overall efficiency.

L'invention décrite concerne un montage d'usinage spécifiquement développé pour simplifier l'usinage précis des surfaces de référence des aubes de turbines.
Bien que son utilisation ne se limite pas à cela, il est particulièrement pertinent dans les domaines de l'énergie et de l'aéronautique, où les aubes jouent un rôle essentiel.
Un moteur à turbine à gaz est généralement composé d'un moteur principal disposant d'un agencement en flux série. Cet agencement comprend un compresseur haute pression chargé de comprimer le flux d'air entrant dans le moteur, une chambre de combustion où se produit la combustion d'un mélange de carburant et d'air, ainsi qu'une turbine équipée d'une pluralité d'ensembles d'aubes. Ces ensembles d'aubes permettent d'extraire l'énergie de rotation du flux d'air sortant de la chambre de combustion.
L'appareil décrit dans cette invention a pour objectif de faciliter l'usinage des surfaces de références des ensembles d'aubes dans les moteurs à turbine à gaz. Ces ensembles d'aubes sont des éléments essentiels pour l'efficacité et les performances du moteur. Par conséquent, il est crucial de pouvoir les usiner avec une grande précision pour garantir leur bon fonctionnement.
L’invention proposée pourrait être une aide importante aux industries de production. Dans ces industries, les aubes sont généralement fabriquées en plusieurs étapes. À chaque étape, certaines caractéristiques sont formées sur les pièces. Ces caractéristiques ne sont pas nécessairement les caractéristiques finales des pièces et sont les surfaces de référence pour l'usinage des surfaces finales.
Si ces surfaces de référence sont mal usinées dans les étapes précédentes, les caractéristiques finales ne sont pas usinées correctement. Ainsi, même si ces éléments de référence peuvent ne pas être importants en eux-mêmes ou pour le fonctionnement de la pièce finale, ils sont importants dans le sens où ils fournissent des surfaces de référence pour les pièces finies finales. Certaines de ces surfaces de référence peuvent même être usinées et supprimées complètement à un certain stade du processus d'usinage. L’invention présentée tente de résoudre ces problèmes et de réduire le coût de production.

This study is a mathematical and geometric proof of the expression of the micro- and nanohardness
of thin coating resulting from the indentation of a needle form of a cone tip. It is geometric and
mathematical modeling of the indentation of the monolayer solid material, where approaches to the
coefficients of the model of surfaces mixture are presented. Firstly, formulations of hardness
indentations of the composite and the substrate of the mono-layer-coated material have been
established. Then, the hardness formula of the thin film of the coating material was derived from the
additive law of mixtures. The project imprint result from the indentation of the cone tip on a plane
surface is considered as a disk form and the coefficients ߙ and ߚ are ratios of circle surfaces. The
hardness of the composite and the substrate of the coating material are expressed as functions of the
imprint projected dimensions and the applied load. The contribution of the film to the composite
hardness is determined by the model of the surfaces – low mixture of the area – low mixture model.
Finally, the expression of the hardness film becomes a function of the composite hardness, the indenter
dimension, the imprint dimension, and the film thickness.

In this paper, the effect of the winding angle and the number of folds on the
delamination behavior of vinyl ester resin-fiberglass composites under mode-I loading was
investigated experimentally. Accordingly, double cantilever beam samples with 8 and 12 folds
and with different winding angles (±45°, ±55° and ±65°) were cut out of industrial pipes and
subjected to mechanical tests. Furthermore, thick films were introduced during the winding
process to create initial cracks of 50mm. The Mode-I fracture tests were conducted according to
ASTM D5528-94a standards. Results show that the [±65°] winding angle provides the best
delamination behavior and greater resistance to cracking compared to the [±55°] and [±45°]
winding angles. Results also show that the number of folds has no effect on the initiation of the
crack stage, but it significantly affects the propagation stage.

The accuracy of a machine tool can be significantly impacted by thermal
deformation, which is a type of thermal error. Thermally induced positioning errors can occur
due to temperature variations that cause the materials in a machine tool to expand or contract,
leading to dimensional changes that affect the accuracy of position measurements. Laser
interferometer measurements can be used to detect these errors by comparing the actual
position of a component to its expected position based on a reference measurement. To control
the thermally induced positioning error of machine tools, a mathematical model that describes
the relationship between temperature and positioning errors is proposed in this paper. The
proposed model is based on empirical data collected from laser interferometer measurements
and then used to predict the magnitude of the errors under different thermal conditions. A set of
tests was conducted to confirm the thermal model's validity. The excellent match between the
experimental data and the calculated values provides evidence supporting the possibility of
using the suggested approach for estimating the thermal performance of CNC machine tools.

Components and sub-assemblies of machinery and equipment will wear out over
time and leads to their destruction and hence production downtime. The easiest and fastest way
to overcome this problem is to replace these elements with a new one. However, the problem
arises when the desired element is not available on the market, the technical documentation is
not available or the costs of obtaining a new item are too high. A good example of this situation
is the industrial problem related to the halt in the spare parts caused by the closure due to the
global spread of the Corona virus. To overcome these problems, reverse engineering can be
used. The best solution is to replicate the desired part digitally. The purpose of this paper is to
solve an industrial problem related to lack of spare parts such as tram transmission gear. The
CAD model of this component is not available, but the finished part (physical part) is available
for reverse engineering. The 3D scanning of the gear was carried out using a FARO LASER
ARM (Non-contact scan) and the obtained point cloud was processed using CAM2 MEASURE
10, CATIA V5.R20 and MATLAB software for surface approximation and geometrical modeling
of scanned part. The CAD model built and the digital version obtained could be used to
continue the reconstruction process and also allows improvements to be made to the part
without generating any additional cost.

The aim of this work to explore the absorption behavior of bio composites reinforced with date palm fibers. RSM
and ANOVA were utilized to evaluate the impact and interdependence of input variables (Time: from 24 h to 672
h, Fiber content: 15 %, 20 %, and 25 %, and types of water: seawater, distilled water, and rainwater) on the
output variables (Mass of CDPF) during a water absorption process that lasted more than 670 h at 23 ◦C. The
findings revealed that the bio composites with the above-mentioned filler content absorbed more water as the
amount of fibers increased, with absorption rates of 14.03 %, 19.39 %, 30.94 % for seawater, 15.42 %, 20.64 %,
and 36.08 % for distilled water, and 16.37 %, 21.98 %, and 42.10 % for rainwater, respectively. Additionally, the
study measured the diffusion coefficient of bio composites, which had a minimum value of about 2.11 ×
10− 6mm2/s and a maximum value of about 3.99 × 10− 6mm2/s. The results of RSM model analysis showed that
this model is accurate and reliable. Where the values of R2 and adjusted R2 coefficients for the Mass of CDPF were
99.63 % and 99.61 %, respectively, indicating an ideal match between experimental and predicted values. These
findings provide valuable information for engineers interested in incorporating date palm fiber bio composites
during development and implementation.

Nowadays, with regard to many environmental problems, the development of environmentally friendly materials such as natural fiber composites is a real alternative to synthetic fibers. They have many interesting advantages such as their availability, their low cost, their low density, their biodegradable character, their specific resistance properties and their low impact on the environment. The present paper is aimed at fabricating and machining of an epoxy composite material reinforced with Alfa (Stipa tenacissima L.) fibers. The full factorial analysis was used to assess the effect of cutting parameters such as cutting velocity and feed rate on the arithmetic roughness Ra of machined surfaces obtained by down milling and up milling operations. For this purpose, a two flutes high-speed steel (HSS) cutting tool was used. The results showed that the up milling mode provides better surface roughness than down milling mode for almost all machined specimens. The feed rate is the main factor affecting the surface roughness, with a contribution of about 90%. The worst values of arithmetic roughness were observed, at low feed rate (0.05 mm/rev) regardless of the cutting velocity. The results also showed that machining parallel to fibers direction (0°) offers better surface roughness than machining perpendicular to fibers direction (90°). Microscopic and SEM images show some defects such as matrix cracking, cavity, fibers breakage, loss of matrix, fluffing, and thermal damage.

Les turbines à gaz sont des équipements essentiels utilisés pour la production d'énergie dans différents secteurs tels que l'industrie, les centrales électriques, l'aviation, entre autres.
L'invention porte sur le développement d'un appareil innovant permettant de maintenir les aubes de turbine lors de leur inspection sur machine à mesurer tridimensionnelle (MMT).
Cet appareil est spécialement conçu pour la fabrication de turbines et d'aubes neuves, et il assure un maintien stable et précis des aubes durant l'inspection. Grâce à cet appareil, les ingénieurs et techniciens peuvent procéder à une inspection détaillée et minutieuse de chaque aube, en veillant à la qualité et à la précision des mesures. L'utilisation de cet appareil permet ainsi d'optimiser le processus de fabrication de turbines et d'aubes, en garantissant des normes de qualité élevées et en assurant un rendement optimal des équipements.
L'invention est particulièrement utile pour les entreprises impliquées dans la fabrication de turbines à gaz et d'ailettes, car elle permet de garantir la qualité et la fiabilité des produits finis. Elle peut également contribuer à réduire les coûts de production en détectant les défauts plus tôt dans le processus de fabrication.

Composite material consumption is booming and is expected to increase exponentially in many industrial applications such as aerospace, automotive, marine and defense. However, in most cases, composite products require further
processing before they can be used or assembled. Machining of composite materials is extremely difcult due to their
anisotropic and non-homogeneous structure. This paper provides a comprehensive review of the literature on composite
materials and their machining processes, such as turning, milling and drilling. Damage related to these processes is also
discussed. The paper is divided into seven main parts; the frst, second and third parts give a brief overview of composite
materials, reinforcements used in composite materials and composite manufacturing methods, respectively. The fourth
part deals with post-processing machining operations, while the ffth, sixth and seventh parts are devoted to the machining of carbon fber reinforced polymer composite, glass fber reinforced polymer and natural fber reinforced polymer
composites, respectively. An analysis of the factors that infuence the machining and the machinability criteria used for
these materials is also presented, with particular emphasis on cutting forces, tool wear, delamination and surface fnish.
Non-traditional manufacturing methods are not discussed in this paper.

The This work studies the drilling performance of bio composites reinforced
with cellulosic fibres. The drilling was carried out at three spindle speeds and at three feed
rates using three dissimilar drills namely: HSS-TITAN, HSS-CARBIDE, and HSS-SUPER. The
drilling performance was evaluated in terms of the delamination factor which was determined
using the free software image J. The results showed that the value of this factor decreased with
increasing spindle speed and increased with increasing feed rate. On the other hand, the HSSSUPER drill causes less delamination than the other two drills. To predict the delamination
value, the artificial neural network (ANN) method was used. The best hole quality was obtained
when using the HSS-SUPER drill, with a spindle speed of 2200 rpm and a feed rate of 40
mm/rev. The worst case was brought when using an HSS-carbide drill, with a spindle speed of
500 rpm and a feed rate of 120 mm/ rev

The present article attempts to study absorption properties of bio-composites reinforced with date palm fibers. The effect of fiber loading on water absorption at room temperature 25°C was investigated. The weight gain was measured of bio-composites immersed in distilled water, seawater and rainwater, for more than 670 hours, until reaching the saturation with a measurement interval between 24 and 48 hours. To understand absorption phenomenon, scanning electron microscopy was used. Porosity rate was determined using image J software. It was noted the water absorption rate of the bio composites reached 16.20%, 16.33%, 21.94%, 41.99% for seawater, 16.41%, 16.52%, 20.84%, 30.08% for distilled water, and 14.00%, 14.04%, 19.30%, 36.94% for rainwater, respectively. The absorption increases when increasing fiber content. The diffusion coefficient of bio-composites has minimum and maximum values of about 1.94 × 10−6mm2/s and 3.99 × 10−6mm2/s, respectively. Palm fibers are highly porous. The porosity value was higher than 51%. To predict the absorption rate, artificial neural network method was used. The ANN models obtained are very well correlated with the experimental data where the values of the correlation coefficient of the datasets are all beyond 0.99 and the average error value was estimated at 3 × 10−5.

Il existe plusieurs types de pièces mécaniques de formes complexes possédant diverses fonctions. Les aubes de turbine sont l'un des composants les plus importants des turbines à gaz. Cependant, ces aubes ont des formes complexes et une courbure de surface irrégulière qui les rendent difficiles à usiner. Alors leur fabrication nécessite des montages spéciaux, qui malgré leurs difficultés de design et leurs coûts, doivent assurer la mise en position, le maintien en position, la rigidité, la précision ainsi que la répétabilité pour toute la série de pièces, sans qu’il y est détérioration ou usure pendant la fabrication de la série. C’est pour cette raison que la conception de ces montages spéciaux doit être faite d’une manière précise, performante et en même temps économique. Comme les besoins de précision de plus en plus augmentent dans l'industrie, de nouvelles configurations et procédés de fabrication des ailettes de turbines à gaz, doivent être développés pour satisfaire les exigences de la production moderne. Donc l’objectif de cette invention est de donner une contribution dans le domaine de la fabrication industrielle tel que, l’aéronautique, l’énergie, et la défense, précisément, dans le domaine de l’usinage des ailettes fixes de turbines sur des machines-outils à commande numérique par le développement de deux dispositifs d’usinage permettant de maintenir les pièces dans une position unique d’une manière répétitive et rigide pendant l’usinage. Ces dispositifs contribuent, de manière significative, à l’amélioration de la productivité des ailettes fixes de turbines, en matière de qualité et de temps d’exécution réduit.

Dans l'industrie manufacturière, il existe plusieurs types de pièces de formes complexes possédant des fonctions diverses. Les aubes de turbine (aubes et palettes) sont l'un des composants les plus importants des turbines à gaz. Cependant, ces aubes ont des formes complexes et une courbure de surface irrégulière qui les rendent difficiles à usiner.
La production de ce type de pièces est très compliquée et nécessite un contrôle élevé du processus d'usinage, une programmation CNC avancée, des outils innovants et des montages spéciaux permettant de maintenir exactement et rigidement une position unique de la pièce pendant l'usinage.
Afin d'améliorer la productivité et de réduire le temps d'opération, augmentant ainsi la qualité des pièces, le dispositif d'usinage doit répondre à plusieurs exigences telles que permettre un positionnement correct avec sécurité et répétabilité de la pièce ainsi que maintenir la conformité et l'interchangeabilité des pièces usinées.
La présente invention relève le défi de l'usinage de pièces à géométrie complexe par le développement et la réalisation d'un dispositif d'usinage (FIG 01), dédié au maintien en position d'une ailette mobile (2) d'une turbine à gaz pendant l’usinage.
Les secteurs de l’énergie, de l’aéronautique et l'industrie de l'usinage profitera de manière significative de cette invention, en augmentant le temps d’usinage des machines (éliminer le temps mort), produire des pièces de haute qualité et de réduire considérablement la variabilité des temps de production tout en répondant constamment aux exigences de tolérance.

This work presents a study of the determination of the temperature at the interface in the dry
friction of the low alloy steel pin against a medium-hard carbon steel disk. The parameters: Normal load
applied, sliding speed, hardness of the material and coefficient of friction resulting during the tribological
tests carried out play a very important role on the thermal effects of the opposing surfaces. The Archard
model was used to determine the temperature at the tribological couple interface, using the parameters
mentioned above.

This work focuses on studying the drilling performance of bio-composites with a palm fiber reinforcement fraction of 40 wt%. The drilling was carried out under dry cutting conditions at three spindle speeds of 500,1100 and 2200rpm and three feed rates of 40, 80, and 120 mm/rev using three 10 mm diameter drills: T1: HSS-TITAN, T2: HSS-CARBIDE, and T3: HSS-SUPER. The drilling performance was evaluated in terms of the circularity and cylindricity of holes that were determined using a CMM device applying the technique of contact scanning. The results showed that the effect of feed rate was greater than spindle speed. It is found that an increase in the feed rate value results in a degradation of circularity and cylindricity: For holes drilled under the following cutting conditions (N=500rpm, ƒ=40mm/rev, and T=T1). The circularity and cylindrical values was 0.0301 and 0.0475 respectively. On the other hand these values rise to 0.0740 and 0.1717, respectively, when drilling under cutting conditions (N = 500 rpm, ƒ = 120 mm/rev and T = T1). It was observed that holes drilled using coated tools (T1 and T2) produced fewer errors than the uncoated tool (T3). The circularity and cylindricity have minimum and maximum values of approximately 0.0180, 0.0852 for circularity, and 0.0475, 0.554 for cylindricity.

In design and manufacturing, tolerancing of parts plays a crucial role due to the incapability of manufacturing process to produce parts with exact sizes and shapes. Furthermore, designing and manufacturing complex shaped parts require optimum tolerance allocation for each part for proper assembly that meets function, cost and quality requirements. Three-dimensional (3D) tolerance analysis methods are important tools for increasingly stringent and complex requirements. The purpose of this paper is to propose a three dimensional (3D) tolerance analysis method for tolerance representation and propagation for mechanical assemblies based on the Jacobian-torsor model. The Jacobian matrix is used for tolerance propagation while the small displacement torsor (SDT) model is used for tolerance representation. The small displacement torsor concept is used as a mathematical tool for analyzing and representing the tolerance information and the geometrical deviations in six degrees of freedom, three translational vectors and three rotational vectors. The method is first applied on an assembly containing two parts, one inserted into the other. The results show that the Jacobian-torsor model is easy to use and allows a great precision over a tolerance zone. The proposed approach presents a useful technique for enhancing the accuracy and reliability of tolerance analysis models for complex shaped parts.

Recently, high performance machining has attracted significant attention from both academia and industry. Machine tool is the key factor to achieve the required quality for high performance machining. One of the main performance criteria for a machine tool is its ability to manufacture dimensionally and geometrically accurate parts. The machine tool is generally affected by various sources of errors that affect its performance and reliability throughout its life cycle. In this context, evaluating the performance of machine tools is important to achieve high precision. The purpose of this paper is to present a technique for assessing and comparing the performance of three different machines tools using two measurement systems. Specific tests methods are used in this work to measure the intra-axes errors of each prismatic axis of the three tested machines. Each machine tool has been measured in a similar area of its working envelope. It is found that the tested machines behave differently, in terms of accuracy, repeatability and backlash errors. On the other hand, although the six intra-axis errors of an axis of a CNC machine tool are defined individually in the literature and in standards, and are usually modeled separately in the literature, it was discovered in this work the presence of a strong correlation between the linear positioning error and the angular error. This finding was confirmed for the three tested machines.
The method proposed in this work for performance verification can also be used for solving the machine tool selection problem for high performance machining.

Due to their economical, technical and environmental advantages natural fibers composites are expected to replace synthetic and hazardous materials in many industrial applications. Understanding the mechanical properties of natural fibers is therefore very important to determine the optimal intended uses of this material. Furthermore, tensile strength is one of the most important characteristic that determines the quality of composite. This paper focuses on the development of a new eco-friendly composite material based on polyester resin reinforced with long Alfa (Stipa tenacissima L) fibers. The effect of alkali treatments on the tensile properties of Alfa fibers is also investigated in this paper. The fibers have subjected to alkaline treatment with 5% NaOH concentration. All treatments were carried out under mild conditions without heating for 24 h. Results show that the alkali treatment enhances the tensile strength and Young's modulus significantly with an increase of around 60% compared to raw fibers. Furthermore, the strength-elongation curves of treated and untreated specimens have the same appearance. The results of this work suggest that local Alfa fibers are comparable to other natural fibers used as reinforcements in polymer matrix composites.

Hole making in composite materials is one of the most expensive and time-consuming
processes in the industry. The quality of holes produced is a critical criterion in all machining methods,
whether traditional or modern. Drill geometry and cutting parameters directly affect holes quality. This
quality can be characterized based on a few criteria, including delamination factor, ovality, surface
roughness, damaged surface layer, fiber breakage, burr formation, and cracking. However, damage due to
delamination is a big concern when drilling composite laminates. The purpose of this paper is therefore to
investigate delamination during drilling of Alfa fiber (Stipa tenacissima) reinforced laminated composites
using a factorial experimental design. A total of 20 tests were carried out covering a spindle speed
varying from 500 to 2500 rpm and a feed from 10 to 40 mm/min under dry conditions and using a high
speed steel (H.S.S.) drill. Based on the tests carried out, the defects created during drilling are analyzed.
First, a defect location analysis is performed followed by fine-tuned microscopic observation to identify
the different types of defects. It is well known that hole quality issues during drilling composite materials
is usually related to the exit side of the hole, however, results of this research show that hole entry defects
are also of a concern. This study is a contribution to a better understanding of the quality of drilled holes
in composite structures reinforced with Alfa fibers, which should lead to improved quality and production
costs.

Machining fixtures are used to securely place and maintain parts in the appropriate position and support them during machining, while ensuring that the parts produced remain compliant and interchangeable. For machining fixtures intended for complex shaped parts, the optimization of positioning supports and clamping elements is the first design step that must be completed. This ensures correct holding and positioning and reduces geometric errors of the workpiece during the machining process. This paper addresses an industrial problem, related to the design and manufacture of a machining fixture for turbine blades. The purpose of this paper is to present, an optimization approach based on a genetic algorithm (GA) to select the optimal positions of the locating supports. The Plückerian coordinates concept was used to build the objective function. The determinant of the information matrix (objective function), is used as a criteria for optimizing the positioning of the machining fixtures locator.
Parts with different shapes have been considered to evaluate the proposed methodology. First, cubic and cylindrical parts which are considered as classic regular shapes are chosen to test the tendency of the proposed algorithm to converge to an acceptable solution. After confirming the efficiency of the proposed algorithm, the approach was then used to optimize the fixture layout for a turbine blade. Results show that the proposed approach is a useful technique for the research and industrial communities in providing them indispensable and automated tools for the rapid development of fixture layouts.

Surface roughness plays an important role in the performance of finished components. Hemispherical milling is usually used to achieve high surface quality, especially in components with complex geometries. However, the surface quality produced is strongly affected by the milling strategy chosen. Different milling strategies can be applied depending on the cutting conditions chosen for hemispherical milling. This paper investigates the effect of the milling direction on the surface roughness of a nickel-based superalloy. A single sweep finish milling parameter is tested using a hemispherical carbide tool. This milling operation was applied to a cylindrical surface segment of a support for horizontal positioning of a gas turbine blade in two distinct directions. A longitudinal direction parallel to the axis of rotation of the cylinder is first tested followed by a test in the transverse direction which covering the entire perimeter of the cylinder. In order to carry out a sufficient number of experiments to draw meaningful conclusions, a certain number of cutting parameters are tested including the extra thickness, the axial and radial pitch of the cut, the feed rate and tool diameters. The two milling strategies are considered and a mathematical model of the surface roughness is established and experimentally validated. Results show that milling along the longitudinal direction provides better roughness values compared to the transverse direction.

This work focuses on the study of the drilling performance of bio composites reinforced with date palm fibers (CDPF). It is a new fiber that is characterized in terms of piercing behavior for the first time. The experimental study was carried out with three types of drills, with a diameter of 10 mm and feed and spindle speeds of the order of (40, 80 and 200 mm/min) and (560, 1120 and 2240 rpm), respectively. The drilling performance was assessed in terms of delamination and surface quality, such as circularity and cylindricity of the drilled holes. Using the CMM machine, the value of the delamination factor was determined using Image J software. The results showed that the value of the latter increased with the increase in feed rate and decreased with the increase in spindle speed. The delamination factor has maximum and minimum values of approximately 1.98 and 1.01 respectively. For the first time, RSM and ANOVA were used to assess the influence and interaction of input parameters (cutting conditions) on the output parameters (delamination factor Fd) during drilling of CDPF. The results obtained help manufacturers, to choose the most appropriate machining conditions to achieve better machinability for other newly developed NFRCs in the aeronautical and defense industry where the substitution of the synthetic fibers by the natural fibers becomes inevitable for economic reasons.

This paper presents an experimental study conducted to assess the correlation between the intra-axis errors of prismatic
axes for CNC machine tools. The validity and reliability of parametric models for the modeling of intra-axis errors (IAEs)
of CNC machine tools in the context of indirect calibration are also assessed in this work. Three CNC machine tools with
various controllers and guidance technologies were tested using two diferent measuring instruments. Two predictive models,
namely Bézier and B-spline curves, are described and compared for the frst time in this work. Both models are experimentally evaluated for accuracy and predictive efciency using four evaluation criteria and new data sets from the three tested
CNC machine tools. Results show a strong correlation between the positioning errors and the pitch and yaw errors for all
the tested machines. The results also show that both proposed models are appropriate for the modeling of intra-axis errors,
with the B-spline curves coming slightly on top in terms of performance. Moreover, with the same number of control points
(n=5), the two models provide residuals that are lower than the repeatability of the machine for most intra-axis errors tested.
This experimental study thus confrms that a Bézier model of degree four and a B-spline model of degree two, both with fve
control points, are sufcient to represent the intra-axis errors for the tested CNC machine tools.

Skin panels are one of the most important components constituting the aircraft structures such as wing and fuselage sections. These thin-walled components were produced from 2024-T3 aluminum alloys and many pockets were usually created in these panels by chemical milling process for weight reduction purpose. However, this process is time consuming due to its slow metal removal rate, its health hazard and its severe significant environmental impact. End-milling could provide an excellent base for creating the panel pockets and maintain the required precision. Nevertheless, maintaining a comparable quality between the two processes is quite challenging due to the dynamic nature of the cutting process and the heat generating during machining. Furthermore, an overheating in the cutting zone generally induces structural variations of the material texture, involving residual stresses and reduces stiffness which leads to damages in the machined panels. In this paper, the effect of cutting conditions on heat generation was investigated experimentally based on Taguchi and full factorial design techniques. A quantitative and qualitative statistical analysis is used to identify relationships among heat generation and process parameters, heat generation and cutting region and finally, heat generation and machining operation. The results showed that the proposed approach can successfully detects the significance or non-significance of the temperature variation between different cutting zones and machining operations.

Replacing glass fiber reinforced composites is the current challenge for flax fiber reinforced composites to reduce cost and weight
of structural components. However, the quality of the machined flax fibers must be comparable to that of glass fiber. Machining a
composite material means before every other consideration cutting the fibers of this material and therefore entails a risk of
damage in the vicinity of the machined zone. The aim of this paper is therefore to compare experimentally the machining quality
of the flax fiber reinforced polymers composite (FFRP) with that of the glass fiber reinforced polymers composite (GFRP) based
on the Split-Split Plot randomized complete block design. Thus, two cutting tools were tested and the most suitable tool for each
material was selected. Based on the experimental results, it was observed that the type of the cutting tool has a significant effect on
the delamination behavior. Furthermore, results show that flax fiber composites can be easily machined, hence no tool wear was
observed. Results also show that a two-flute uncoated carbide end mill tool is more suitable for trimming flax fiber composite
while a two-flute polycrystalline Diamond end mill (PCD) tool is better suited for trimming GFRP. The lowest delamination
(uncut fiber) was observed at 0º and 45º ply orientation for both materials.

This paper attempts to highlight some of the most common problems facing the machining of flax fiber composite. The essential aspects of modeling surface roughness of flax-fiber composite are also covered in this work. The most appropriate model for predicting surface roughness is then selected. The trimming experiments were conducted based on the Split-Split Plot randomized complete block design, varying the cutting velocity, feed, cutting tool geometry and fiber orientation as cutting parameters against surface roughness and delamination as responses. Accordingly, two cutting tools were tested and the most suitable tool was selected. Results show that the two-flute uncoated carbide end mill tool with cutting profiles of 70° (tool # 2) provides more accurate and repeatable results than the two-flute polycrystalline Diamond end mill (tool # 1). Results also show that the B-spline model provides more accurate estimates of the surface roughness than the two other proposed models.

In the manufacturing industry, there are several types of parts of complex shapes owning various functions. The
turbine blades (buckets and vanes) are one of the most important components in gas turbines. However, these blades
have complex shapes and irregular surface curvature which make them difficult to machine. Production of such kind
of parts is so complicated and requires a high control of machining process, advanced CNC programming, innovative
tools, and special fixtures allowing to maintain exactly and rigidly in a unique position of the part during machining.
In order to enhance productivity and reduce operation time, thereby increasing parts quality, the machining fixture has
to fulfill several requirements such as allowing a correct location with security and repeatability of the workpiece as
well as maintaining conformity and interchangeability of the machined parts. This paper addresses the challenge of
machining complex geometry parts by development and realization of a dedicated machining fixture (MF) for holding
a mobile blade of a gas turbine. The first novelty of this work is in the application of the Plückerian coordinates
method for choosing the locator’s placement of complex-shaped parts. The choice of the locator’s placement during
the design process of the fixture is performed based on the maximization of the determinant and minimization of the
condition number of the locator matrix (information matrix). The second novelty is in the optimization approach used.
The last novelty is in the developed and fabricated machining fixture. The performance of the developed fixture in
terms of localization repeatability is evaluated based on the small displacement torsor (SDT) concept. Results show the
validity of the developed fixture.

Although CFRP materials are gaining popularity, their processing is still poorly understood. Accurate and repeatable models related to the cutting mechanism of CFRPs remains challenging. This work represents an investigation into the use of parametric models as an alternative approximation technique for modeling cutting force and surface roughness during high speed edge trimming of CFRP. Three predictive models were described and compared, some of which have been rarely used in this application. The three developed models were evaluated in terms of their accuracy and efficiency using new set of data (external data) and four evaluation indices. Result shows that Bezier models outperform regression models and can be used as alternative for modeling and prediction of machining responses. Although kriging model predict the internal data accurately, it breaks down when using external data. The new selected model can help the manufacturing industries for monitoring the cutting process of CFRPs.

C V D d i a m o n d - c o a t e d c a r b i d e t o o l s c o u l d p r o v i d e a n e c o n o m i c al alternative for trimming CFRPs components compared to their PCD tools counterpart. Nevertheless, there are still some technical issues to understand related to wear resistance and surface quality. In this work, a CVD tool with six straight flutes was used to investigate the relationship between surface roughness, surface damage, tool wear, cutting force and cutting parameters during the high speed trimming of CFRPs. Statistical techniques for identifying and selecting the best cutting conditions for CVD tool are developed. In terms of tool wear, results show that the best operational condition to minimize the tool wear is achieved at lower feed rates and higher cutting speeds. Experimental results show also that a 0° ply orientation represents the worst case and produces the maximum tool wear. Furthermore, a strong correlation between the feed force and the tool wear was observed. It was found that the surface roughness decreases as a reciprocal function of cutting length. This decrease was due to the matrix burning/sticking and the thermal damage related to the low thermal conductivity of CFRP. In such situation, Ra becomes inappropriate indicator for roughness evaluation. On the other hand, it wasn’t seen any type of delamination or fiber pull-out on the trimmed surface of all coupons for the three tool life tests. Accordingly, delamination can be avoided using high fixture rigidity, high quality of CFRP laminates, a suitable cutting tool and stable operational conditions.

In this paper, an experimental approach has been developed and implemented to assess the capability of a heavyduty six-axis robot to machine CFRP parts. A simple technique based on fast Fourier transformation (FFT)
analysis is devised and applied to identify the relevant sources of errors during high speed robotic trimming. A strategy based on statistical tests was investigated to quantify and predict the relative contribution of the cutting
parameters and machining strategy on the cutting force components, path deviation and heat dissipation during machining. Machining quality was quantified in terms of surface damage, delamination and workpiece form
errors. Statistical analysis of the experimental results reveals a strong dependence between parts accuracy, cutting direction, and robot position. An experimental model was developed to represent and predict the cutting
force and the path deviation during machining. An excellent error prediction capability was observed. Results show also that the temperature in the cutting zone increased with the increase in feed rate. It was found that at
high feed rate and high cutting velocity, delamination and workpiece form errors were the most sources of error affecting the accuracy of the machined parts. Results show also that the surface quality was significantly affected
by the presence of many empties grooves due to fibers pull out.