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The manufacture of machined components for the aeronautics industry often involves the removal of large quantities of material, while the stringent demands on quality require special care to be taken during the manufacturing process. For most components of this kind, the principal source of distortion is the relaxation of residual stress after the...
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Ceramics can be used in many applications including aeroengine turbine blades, gas turbine blades, high performance bearings and many other applications that require high temperatures service; however, these ceramics are subjected to thermal and mechanical stresses during/while being used in service. Residual stresses may eventually cause microcrac...
Citations
... Under external cutting load, the removal process of thin-walled parts will cause the release and redistribution of initial residual stress, which together with the machining residual stress will result in machining deformation. Among them, the initial residual stress is the main cause of machining deformation [5], and the machining residual stress will have an important impact on the subsequent deformation of the parts [6]. Therefore, in general, residual stress needs to be avoided during machining. ...
Thin-walled aerospace parts have the characteristics of large size, thin wall thickness and complex shape, etc. In the process of machining, poor rigidity and high material removal rate are easy to cause machining deformation due to uneven distribution of residual stress, and conventional detection methods and regulation means can not meet the needs of on-site production. In order to solve these problems, an effective method of ultrasonic nondestructive in-situ stress detection and ultrasonic stress regulation is proposed in this paper. Firstly, the ultrasonic residual stress detection and ultrasonic stress regulation are analyzed theoretically, and their working principles are explained, which provides a theoretical basis for the subsequent use of the equipment. Then, according to the deformable sections of large thin-walled parts in the production site, the typical characteristics are extracted to complete the design of the experimental part, and the residual stress detection and regulation of the whole machining process are studied. Finally, through two groups of comparison experiments, the changes of residual stress values in different depth ranges of parts and the changes of the flatness of the final parts are analyzed. The results show that the ultrasonic critical refraction longitudinal wave (L CR wave) method can be used to detect the residual stress of thin-walled parts in different depth ranges, and the ultrasonic stress regulation method can reduce and homogenize the stress of thin-walled parts, and the machining deformation and conformal ability of the parts are significantly improved after the stress regulation.
... By obtaining the residual stress field in the workpiece, it becomes possible to optimize the preparation process of the blank, and produce blank with minimized residual stress amplitudes and more uniform distributions [8]. Furthermore, the machining process can be optimized to ensure the machining quality of structural component [9,10]. ...
The residual stress field of structural components significantly influences their comprehensive performance and service life. Due to the lack of effective representation means and inference methods, existing methods are confined to inspecting local residual stress rather than the entire residual stress field, rendering the inference of complex residual stress fields quite difficult. In response to the challenges associated with the requirement for extensive sets of deformation force data from the current workpiece and the inherent difficulty in establishing a stable relationship between deformation forces and residual stress fields, this paper introduces a novel inference method of residual stress field is proposed based on a data-causal knowledge fusion model, where causal knowledge is introduced to eliminate the coupling effect of geometric change on residual stress, which can make up the drawback of pure data driven model. The proposed approach can accurately inference the residual stress within the workpieces, which provides an important basis for deformation control and part property improvement.
... The findings demonstrate that the workpiece's stored strain energy can be sufficiently released in the initial stages of machining by optimizing the material removal sequence. A nondestructive approach to determine the intrinsic residual stress condition was created by Casuso et al. (2020). The optimum machining sequence among the choices that produce the same final part is identified by modelling and simulating of various machining sequences of an aeronautical turbine component. ...
In the machining of monolithic components, machining distortion is a severe issue. The presence of initial residual stress is a major contributor to machining distortion. This paper proposes an approach to control the machining distortion of long beam parts by optimizing the workpiece structure before the start of the finishing stage, i.e. the transition structure. The first step is to establish a machining distortion analytical model for long beam parts with an identical cross-section, which is based on reasonable assumptions such as material linear elasticity and ignoring the influence of cutting heat. Then, an optimization model for the cross-section of the transition structure is developed, with the objective function defined as the minimum difference between the predicted distortion of the final part and the transition structure. Finally, a U-shaped beam is designed, followed by numerical simulation and machining experiments for verification. The theoretical maximum distortion of the optimized transition structure and the final part are −0.174 and −0.1782 mm, respectively, with a relative error of 2.9 %. The results of machining experiments and finite-element simulation demonstrate the effectiveness of the proposed model.
... The modeling of residual stresses for optimal machining performance is a good practice to improve the structural integrity of the machined parts. However, this practice can be costly in terms of computational power requirements as well as the equipment required to measure residual stresses [82]. In another study, Fuh and Wu [83] proposed a mathematical model to predict residual stresses in Al2014-T6 alloy during milling. ...
Aluminum alloys are widely used in many industries, including aerospace, automotive, civil, and electrical engineering. When compared to pure aluminum, most aluminum alloys have lower electrical and thermal conductivity, corrosion resistance, and weldability, as well as a low density and specific gravity. At the same time, the properties of aluminum alloys vary significantly depending on the group, which has a significant impact on their machinability. This review article is focused on the study of machining characteristics of aluminum alloys, such as machinability, surface integrity, tool wear and tool life, material removal rate (MRR), and chip morphology. The directions of increasing machinability by controlling cutting parameters, cutting environment, such as dry machining, conventional cooling systems, minimum quantity of lubricant (MQL), cryogenic lubrication (CL), with tool geometry, and textured tools, are also considered; tool materials include coating, vibration, thermally, and hybrid assisted machining. The article discusses the main types of machining, namely, turning, milling, drilling, and grinding. It shows ways to increase the machinability of machining on aluminum alloys, as well as the advantages and disadvantages. From the literature, it can be concluded that tool wear when machining aluminum alloys is 30–40% lower than when machining steel alloys due to their higher ductility and lower strength. Surface integrity, affected by the cutting parameters and cutting temperatures — which can reach between 200 and 400 °C — can vary by up to 15% in hardness and 20% in surface roughness. Cutting tool characteristics can enhance surface finish by up to 25% and extend tool life, reducing edge formation by up to 30%. Chip morphology, influenced by factors such as cutting parameters and tool material, can improve tool life by up to 35%. Vibration techniques can reduce thermal effects and improve surface finish by up to 40%, reducing cutting forces by around 30%.
... Many thin-walled components are milled to remove more than 90% of the initial blank, and the IRS can influence distortion in machined parts [3]. Many studies have shown that the IRS is the main cause of the deformation of thin-walled components [4][5][6]. At the same time, when the blank containing IRS undergoes subsequent machining, the superposition of external load and residual stress breaks the internal stress balance. ...
The residual stress fields of the initial billet and subsequent machining in the material bring great challenges to the precision machining and geometrical stability of aluminum alloy thin-walled components. To ensure that a certain type of large-sized aluminum alloy thin-walled antenna has a small flatness deformation during forming, this paper firstly employed the ultrasonic critical refraction longitudinal wave (LCR wave) detection method to measure the different depth ranges’ residual stress distribution of 5A06/6061/7075 aluminum alloy plate, both as blanks and after multiple milling. Additionally, the effects of inherent residual stress (IRS) and machining-induced residual stress (MIRS) on the subsequent milling deformation were analyzed. After that, combined with the self-developed ultrasonic stress relief (USR) system, the deformation control effect of a thin-walled plate after eliminating residual stress in each stage was tested. The results show that the ultrasonic stress relief treatment can quickly and efficiently eliminate the IRS and MIRS with small flatness deformation. By introducing the URS treatment in the blank, rough machining, and semi-finishing stages, the components before each subsequent machining are in a low-stress state, and the component deformation can be gradually controlled so that the final thin-walled antenna has a smaller flatness.
... The material removal strategy also affects the distortion of thick plates during the machining process [14,22,23]. Different material removal strategies can change the sequence and manner of residual stress release, so the machining distortion of thick plates can be reduced with a suitable material removal strategy. ...
In this paper, the effects of material removal strategies and initial stress states on the machining deformation of aluminum alloy plates were investigated through a combination of finite element simulation and experiments. We developed different machining strategies described by Tm+Bn, which removal m mm materials form top and n mm materials from the bottom of the plate. The results demonstrate that the maximum deformation of structural components with the T10+B0 machining strategy could reach 1.94 mm, whereas with the T3+B7 machining strategy was only 0.065 mm, decreasing by more than 95%. The asymmetric initial stress state had a significant impact on the machining deformation of the thick plate. The machined deformation of thick plates increased with the increase in the initial stress state. The concavity of the thick plates changed with the T3+B7 machining strategy due to the asymmetry of the stress level. The deformation of frame parts was smaller when the frame opening was facing the high-stress level surface during machining than when it was facing the low-stress level. Moreover, the modeling results for the stress state and machining deformation were accurate and in good accordance with the experimental findings.
... As a downside, the material tested was all of their aluminum of the series 7xxx, and the targeted test specimens had simple geometries, which still leaves room for exploring the use of this methodology in other materials and geometries. In this regard, other authors also introduced their own workflows in different materials [91,222] and geometries [73,223], from which the methodology described by Cerutti et al. [146] highlights because the big number of conditions tested, as well as, the use of on-site measurements. ...
Machining precision components involves challenging distortion issues that entail high costs and material and energy waste to the industry. In parallel, advanced control of production processes is a rapidly growing field because of its unique capabilities to solve multi-agent nonlinear problems and develop control actions based on knowledge and experience. Despite the several studies carried out on the subject, research keeps fragmenting distortion issues in different niches of components, and comprehensive reviews considering distortion as a cross-cutting technical hitch have never been reported. In this paper, a study compiling recent advances in machining distortion control from a holistic perspective is presented. For the first time, distortion understanding is unified, offering a new perspective, more practical and comprehensive, which includes intelligent systems. This novel way of attaining the research on distortion distinguishes three interconnected pillars: distortion source identification and quantification, distortion simulation model development, and control strategies drafting and application. The paper guides the reader through several distortion investigations of different kinds and provides classifications never addressed in the field with which a profound understanding of the issue can be achieved. Finally, future trends and key enabling technologies to drive the advanced control and minimization of machining distortions are outlined.
... To improve the surface finish and edge quality of machined components, a finite element and analytical method of microstructure during machining of high-volume fraction SiCp/Al composite alloys is presented [103]. To improve the quality of machined parts by reducing residual stress during machining operations, residual stress and displacement simulation on aviation aluminum alloy parts through milling process optimization is presented [104]. Machining of aluminum alloys and the generated residual stress during machining operations is reviewed in order to increase quality of al alloys machined parts [105]. ...
Due to friction, chip forming, and the induced heat in the cutting area, produced parts by using machining operations have residual stress. Residual stresses caused by machining processes have a major effect on the fatigue life of machined components, which can shorten their service life. In order to increase the performance of machined parts in real-world applications, such as fatigue life, corrosion resistance, and component distortion, residual stress should be investigated and minimized. As a result, predicting and controlling residual stresses caused by machining operations is important in terms of quality enhancement of machined parts. This paper reviews the recent achievements in the machining-induced residual stress in order to be analyzed and decreased. Different methods of the residual stress measurement Destructive Methods, Semi-Destructive Methods and Non-Destructive Test (NDT) Methods are reviewed and compared in order to be developed. In order to minimize residual stress in machined parts, the study examines the effects of machining process parameters, high-speed machining conditions, coolant, cutting tool wear, edges, and radius on residual stress. Analytical and semi-analytical modeling, numerical and FEM simulation techniques of residual stress are reviewed to include advanced methods of residual stress modeling methodology to predict residual stress in machined components. Residual stress in various alloys such as AL alloys, biomedical implant materials, hard to cut materials such as nickel-based alloys, Titanium Based Alloys, Inconel Based Alloys, and stainless-steel alloys is investigated in order to provide efficient residual stress minimization methods in machined components. It has been realized that evaluating and analyzing recent advances in published papers will contribute to develop the research field.
... Monitoring points were employed to optimize the machining sequence which was adaptively adjusted in each machining layer. Casuso et al. [13] proposed a novel methodology for the machining operation with an optimized machining sequence. Aerospace turbine component deformation was reduced 72.6% by using the rebalanced machining sequence. ...
In the process of machining aircraft monolithic components, the initial stress in the blank will cause machining deformation. Based on the energy method, an analytical mathematical model of machining deformation is presented in this paper. The key point is to transform the energy in the removed material into the deformation energy of the part after machining. The initial residual stress of 7050-T7451 aluminum alloy blank and single frame part are used as investigated cases in the analytical model. For layer by layer machining, the deformation evolution is closely related to the tensile or compressive properties of the initial stress of removed material. Combined with the change of neutral axis position, the machining deformation is calculated by a theoretical model. Then, utilizing the semi-analytical model of equivalent bending stiffness, FEM simulation is carried out to analyze the influence of stiffening ribs on machining deformation. Furthermore, experiments are set up to verify the validity of the theory and FEM data. The results indicate that the deformation results of the experiment are consistent with that of theory and FEM model. Deformation is determined by energy of removed material. This paper provides a novel theoretical approaches for the further investigation of this issue.
... Achieving good surface quality in final parts is a widespread concern among manufacturers of all kinds. The milling of thin parts is an especially critical issue [1], since the stiffness of these parts is low, which eases the appearance of vibration, as chatter and forced vibration, which negatively affect final surface quality and tool life [2]. This problem can lead to the rejection of these parts or to the necessity of reprocessing, which entails high costs in terms of material, time, and energy. ...
Thin floor machining is a challenging and demanding issue, due to vibrations that create poor surface quality. Several technologies have been developed to overcome this problem. Ad hoc fixtures for a given part geometry lead to meeting quality tolerances, but since they lack flexibility, they are expensive and not suitable for low manufacturing batches. On the contrary, flexible fixtures consisting of vacuum cups adaptable to a diversity of part geometries may not totally avoid vibrations, which greatly limits its use. The present study analyses the feasibility of thin floor milling in terms of vibration and roughness, in the cases where milling is conducted without back support, a usual situation when flexible fixtures are employed, so as to define the conditions for a stable milling in them and thus avoid the use of ad hoc fixtures. For that purpose, the change of modal parameters due to material removal and its influence on chatter appearance have been studied, by means of stability lobe diagrams and Fourier Transform analysis. Additionally, the relationship between surface roughness and chatter frequency, tooth passing frequency, and spindle frequency have been studied. Ploughing effect has also been observed during milling, and the factors that lead to the appearance of this undesirable effect have been analyzed, in order to avoid it. It has been proven that finish milling of thin floors without support in the axial direction of the mill can meet aeronautic tolerances and requirements, providing that proper cutting conditions and machining zones are selected.
