Recent Progress of Thin Wall Machining

A special issue of Machines (ISSN 2075-1702). This special issue belongs to the section "Material Processing Technology".

Deadline for manuscript submissions: closed (30 June 2023) | Viewed by 13310

Special Issue Editor

School of Mechanical Engineering, Dalian University of Technology, Ganjingzi District, Dalian 116024, China
Interests: tool path; sculptured surface; machining dynamics; adaptive machining; NC machining
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Many thin-wall parts, such as aircraft structural parts, impellers, and turbine blades, are widely used in the fields of aviation, aerospace, energy, and other fields. Manufacturing thin-wall parts to enable their high performance is currently very challenging. These thin-walled parts are very crucial because they generally make the core functions of high-end equipment possible. At the same time, these high-added-value products are becoming increasingly sophisticated, which means their thin-walled sub-structures with need to be built with increasingly higher accuracy in geometry and performance. Currently, there are many barriers that manufacturers face in creating thin-walled parts with the desired shapes and properties due to their complex geometry, complicated thermal–mechanical coupling effects, low structural rigidity, time-varying dynamic characteristics, difficult-to-cut materials, and so on. Therefore, related theories and technologies that embrace chatter detection and suppression, tool path optimization, the control of residual stress distribution, etc., are vital to the manufacture of thin-walled parts with high accuracy and efficiency.

The aim of this Special Issue is to provide a platform for research that addresses challenges and advanced theories in the manufacture of thin-wall parts, which will be beneficial to both researchers and manufacturers. Both original research and review articles related to thin-walled components are welcome.

Potential topics include (but are not limited to) the following:

  • Machining dynamics, stability prediction, and chatter suppression theory/technology;
  • Deformation and compensation theory/technology;
  • Tool path design and optimization;
  • Cutting force prediction;
  • Residual stress prediction and control theory/technology;
  • Simulation theory/technology using finite element methods (FEM);
  • Surface-integrity control theory/methods/technology;
  • Computer-aided design theory/methods.

Prof. Dr. Yuwen Sun
Guest Editor

Manuscript Submission Information

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Published Papers (10 papers)

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Research

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14 pages, 3739 KiB  
Article
A Cyclic Calibration Method of Milling Force Coefficients Considering Elastic Tool Deformation
by Chang Yang, Rong Yu and Shanglei Jiang
Machines 2023, 11(8), 821; https://doi.org/10.3390/machines11080821 - 10 Aug 2023
Cited by 1 | Viewed by 642
Abstract
In metal-cutting technology, milling plays an important role in the product development cycle. The accurate modeling and prediction of milling forces have always been research hotspots in this field. The mechanical model based on unit-cutting force coefficients has a high prediction accuracy of [...] Read more.
In metal-cutting technology, milling plays an important role in the product development cycle. The accurate modeling and prediction of milling forces have always been research hotspots in this field. The mechanical model based on unit-cutting force coefficients has a high prediction accuracy of cutting forces, and it is therefore widely used in the modeling of milling forces. The calibration of the cutting force coefficients can be realized by linear regression analysis of the measured average milling forces, but it needs to carry out multiple groups of variable feed slot milling experiments with full radial depth of cut, and it cannot well represent the interaction condition in peripheral milling with a non-full radial depth of cut. In peripheral milling, the tool will inevitably deform under the influence of cutting force in the direction perpendicular to the machining surface. If the force-induced deformation is ignored, the calibration of the cutting force coefficients will be out of alignment. For this non-slot milling condition where one side of the tool is mainly stressed, a cyclic calibration method for milling force coefficients considering elastic deformation along the axial contact range is proposed. Firstly, the cutting force coefficients are preliminarily calibrated by the experimental data, and, secondly, tool deformation is calculated through a preliminarily calibrated cutting force model cycle until convergence, before cutting boundaries are updated. The cutting force coefficient is then calibrated again, and it is brought back to the cantilever beam model in order to calculate the tool deformation again. The above process is repeated until the cutting force coefficient is convergent. Finally, the cutting force coefficients are obtained in order to predict and model the milling forces. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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25 pages, 8330 KiB  
Article
Research into Dynamic Error Optimization Method of Impeller Blade Machining Based on Digital–Twin Technology
by Rongyi Li, Shanchao Wang, Chao Wang, Shanshan Wang, Bo Zhou, Xianli Liu and Xudong Zhao
Machines 2023, 11(7), 697; https://doi.org/10.3390/machines11070697 - 01 Jul 2023
Viewed by 1026
Abstract
A TC4 impeller blade is a typical weak, rigid, thin–walled part. The contact area between a cutting tool and a workpiece has strong time–varying characteristics. This leads to a strong non–linear variation in cutting load. So, in this kind of part, the processing [...] Read more.
A TC4 impeller blade is a typical weak, rigid, thin–walled part. The contact area between a cutting tool and a workpiece has strong time–varying characteristics. This leads to a strong non–linear variation in cutting load. So, in this kind of part, the processing error is difficult to control. To solve this problem, a method of processing error prediction and intelligent controlling which considers the effect of tool wear time variation is proposed by combining digital–twinning technology. Firstly, an iterative model for digital–twin process optimization is constructed. Secondly, an iterative prediction model of the machining position following the milling force and considering the effect of tool wear is proposed. Based on these models, the machining error of the TC4 impeller blade under dynamic load is predicted. Dynamic machining error prediction and intelligent control are realized by combining the digital–twin model and the multi–objective process algorithm. Finally, the machining error optimization effect of the proposed digital–twin model is verified via a comparison experiment of impeller blade milling. In terms of the precision of milling force mapping, the average error after optimization is less than 8%. The maximum error is no more than 14%. In terms of the optimization effect, the average error of the optimized workpiece contour is reduced by about 20%. The peak contour error is reduced by approximately 35%. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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17 pages, 7126 KiB  
Article
Analysis and Optimization of Milling Deformations of TC4 Alloy Thin-Walled Parts Based on Finite Element Simulations
by Jiaquan Tang, Congying Deng, Xuhui Chen and Haiyan Zhai
Machines 2023, 11(6), 628; https://doi.org/10.3390/machines11060628 - 06 Jun 2023
Cited by 1 | Viewed by 961
Abstract
TC4 (DIN3.7164/5) alloy thin-walled parts are widely used in aviation and aerospace industries. However, due to their special structure, shape and poor machinability, large milling forces and milling deformation often occur in the milling process, which cannot guarantee the machining quality and accuracy. [...] Read more.
TC4 (DIN3.7164/5) alloy thin-walled parts are widely used in aviation and aerospace industries. However, due to their special structure, shape and poor machinability, large milling forces and milling deformation often occur in the milling process, which cannot guarantee the machining quality and accuracy. The milling processing parameters and milling geometric parameters have a significant impact on the milling force and the deformation, and optimization of the influence factors of milling deformations is important for milling quality. Considering that performing milling experiments under multiple conditions is often costly and time-consuming, this paper provides a finite-element-simulation-based method to study effects of the factors on the forces and deformations during milling thin-walled parts. Firstly, using ABAQUS, a finite element simulation model of the milling process of thin-walled parts is established. Additionally, an orthogonal experimental scheme is designed for optimization of the milling parameters, so as to determine the optimized experimental scheme, and then the optimized experimental scheme is verified to reduce the milling force and deformation by finite element simulations. The optimal parameters for a minimal milling force are a spindle speed of 2000 r/min, a feed rate per tooth of 0.04 mm/z, a milling depth of 1.6 mm, a milling width of 1 mm, a diameter of 6 mm, a rake angle of 20°, a tilt angle of 45°, and two teeth. Similarly, the optimal parameters for minimal node deformations are a spindle speed of 4800 r/min, a feed rate per tooth of 0.18 mm/z, a milling depth of 1 mm, a milling width of 1 mm, a diameter of 16 mm, a rake angle of 20°, a tilt angle of 40°, and four teeth. In addition, this paper uses an optimization algorithm to fit the empirical function with a certain practical value, which can provide a reference for the machining of TC4 titanium alloy. By doing so, we can optimize the milling parameters to obtain the desired machining quality and accuracy, while also saving on time and resources. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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18 pages, 6526 KiB  
Article
Study of Surface Integrity of SiCp/Al Composites Using High-Speed Milling under Cryogenic Liquid Nitrogen Conditions
by Huiping Zhang, Liqiang Qu and Chenglong Ding
Machines 2023, 11(6), 608; https://doi.org/10.3390/machines11060608 - 02 Jun 2023
Cited by 1 | Viewed by 948
Abstract
In order to study surface roughness, surface morphology, surface microhardness, and surface residual stress, single-factor and central combination high-speed milling testing of SiCp/Al composites was carried out using a PCD tool under cryogenic liquid nitrogen cooling conditions. The test results show that the [...] Read more.
In order to study surface roughness, surface morphology, surface microhardness, and surface residual stress, single-factor and central combination high-speed milling testing of SiCp/Al composites was carried out using a PCD tool under cryogenic liquid nitrogen cooling conditions. The test results show that the surface roughness value gradually increases with an increase in feed or milling depth, and the interaction between the two can make this phenomenon more serious. When the milling speed changes at 200~360 m/min, the surface microhardness and surface residual stress first increase, and then, become smaller, so it is recommended to use a speed above 240 m/min for milling under cryogenic liquid nitrogen cooling conditions. With an increase in milling depth and feed, the degree of surface microhardness is significantly improved, and the residual compressive stress also has a tendency to convert to residual tensile stress. In addition, it can be seen from the simulation results that as the milling depth and feed per tooth increase, the interference effect of the SiC particles on internal residual stress transfer also increases. Therefore, it is not recommended to use both high milling depths and high feed per tooth. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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18 pages, 10594 KiB  
Article
Construction Method of Digital Twin System for Thin-Walled Workpiece Machining Error Control Based on Analysis of Machine Tool Dynamic Characteristics
by Wenkai Zhao, Rongyi Li, Xianli Liu, Jun Ni, Chao Wang, Canlun Li and Libo Zhao
Machines 2023, 11(6), 600; https://doi.org/10.3390/machines11060600 - 01 Jun 2023
Cited by 1 | Viewed by 1233
Abstract
In the intelligent optimization process of aerospace thin-walled parts, there are issues such as solidification of core knowledge base, high system coupling degree, and real-time evaluation and optimization feedback required for the knowledge base. These problems make it difficult to expand the functions [...] Read more.
In the intelligent optimization process of aerospace thin-walled parts, there are issues such as solidification of core knowledge base, high system coupling degree, and real-time evaluation and optimization feedback required for the knowledge base. These problems make it difficult to expand the functions of the digital twin system and meet the growing processing needs, ultimately hindering the application of digital twin technology. To address these issues, a digital twin system for controlling processing errors in thin-walled parts was built using a microservices architecture. In addition, a method for building a digital twin system at the processing unit level with the best coupling degree was proposed, mainly targeting the dynamic characteristics analysis knowledge base of thin-walled parts. Furthermore, to meet the requirements for backward compatibility of the processing unit level digital twin system, a comprehensive solution including the construction, operation, evaluation, optimization, and visualization of a knowledge base for the dynamic characteristics of the processing unit was proposed, providing guidance for the digital transformation and upgrading of CNC machine tools and the optimization of processing technology based on digital twin technology. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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18 pages, 7520 KiB  
Article
PSO-Based Feedrate Optimization Algorithm for Five-Axis Machining with Constraint of Contour Error
by Jingwei Yang, Xiaolong Yin and Yuwen Sun
Machines 2023, 11(4), 501; https://doi.org/10.3390/machines11040501 - 21 Apr 2023
Cited by 1 | Viewed by 1261
Abstract
Feedrate has a great influence on contour error in five-axis machining. Accordingly, it is of great significance to plan the time-optimal feedrate curve considering the contour error constraint to achieve high-accuracy and high-efficiency machining. Aiming at improving the error control accuracy of model [...] Read more.
Feedrate has a great influence on contour error in five-axis machining. Accordingly, it is of great significance to plan the time-optimal feedrate curve considering the contour error constraint to achieve high-accuracy and high-efficiency machining. Aiming at improving the error control accuracy of model linearization loss and optimizing the machining time, the PSO-based feedrate optimization algorithm for five-axis machining with constraint of contour error is proposed in this paper. Firstly, the relationship between parametric feedrate and contour error constraint is clarified that provides a model basis for accurately controlling contour error by optimizing the feedrate curve. Then, the feedrate optimization model, which takes the control vertices of the feedrate curve expressed by B-spline as the decision variables and minimizes the machining time as the optimization objective, is established. Subsequently, to overcome the shortcomings of low accuracy and low efficiency caused by single optimization of global control vertices, the group search particle swarm optimization (GSPSO) algorithm based on window movement is adopted to optimize the feedrate curve in segments. Finally, the effectiveness of the proposed feedrate optimization algorithm is validated by three typical test toolpaths on an open double-turntable five-axis machine tool. In light of the experiment, the proposed algorithm is able to fully release the potential of the machine tools while accurately controlling the contour error of the cutter tip and cutter orientation. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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20 pages, 6492 KiB  
Article
Development of Pneumatic Force-Controlled Actuator for Automatic Robot Polishing Complex Curved Plexiglass Parts
by Xinyu Zhang and Yuwen Sun
Machines 2023, 11(4), 446; https://doi.org/10.3390/machines11040446 - 01 Apr 2023
Cited by 2 | Viewed by 1747
Abstract
Due to the temperature-sensitive characteristic of plexiglass materials, it is necessary to maintain a constant small contact force to avoid surface burn damage when polishing complex curved plexiglass parts. To handle the issue, in this paper a pneumatic force-controlled actuator was developed to [...] Read more.
Due to the temperature-sensitive characteristic of plexiglass materials, it is necessary to maintain a constant small contact force to avoid surface burn damage when polishing complex curved plexiglass parts. To handle the issue, in this paper a pneumatic force-controlled actuator was developed to keep the normal contact force between the polishing tool and the workpiece constant during the robotic polishing process. The force-controlled actuator is configured with a double-acting cylinder as the driving element, and two electrical proportional valves are used to control the output force by adjusting the pressure difference between the two air chambers of the cylinder. In this case, a small contact force can be exactly achieved, and the cylinder can always work within the optimal pressure range. In order to judge the stability of the system and reduce the commissioning time of the force-controlled actuator, a mathematical model of the force-controlled actuator is established. Meanwhile, for eliminating the influence of the gravity of the polishing tool on the contact force control, a gravity compensation algorithm is also given according to the roll-pitch-yaw (RPY) angle calculation method. Since there are some nonlinear factors in the operation of the force-controlled actuator, a fuzzy proportion-integral-derivative (PID) control strategy is adopted without steady-state errors. Finally, the polishing experiment of a complex curved plexiglass part was carried out by using the robot automatic polishing system. The experimental results show that the contact force control effect of the force-controlled actuator meets the processing requirements, and the curved plexiglass part has good surface quality and optical performance after polishing. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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18 pages, 4127 KiB  
Article
Lubrication Mechanism of scCO2-MQL in the Assisted Machining of Titanium Alloys
by Limin Shi, Tong Wang, Erliang Liu and Ruyue Wang
Machines 2023, 11(2), 291; https://doi.org/10.3390/machines11020291 - 15 Feb 2023
Cited by 3 | Viewed by 978
Abstract
Cutting fluids are often used in the machining of titanium alloys to reduce processing temperature and maximize quality and productivity. The permeability of the cutting fluid in the capillary tube directly influences the effect of lubrication on cooling performance. In this study, supercritical [...] Read more.
Cutting fluids are often used in the machining of titanium alloys to reduce processing temperature and maximize quality and productivity. The permeability of the cutting fluid in the capillary tube directly influences the effect of lubrication on cooling performance. In this study, supercritical carbon dioxide cryogenic micro-lubrication (scCO2-MQL) is used for the auxiliary machining of titanium alloys. A capillary model for scCO2-MQL-assisted cutting is proposed and established while considering the characteristics of three-phase states produced during the decompression release of scCO2. The injection temperature and characteristics of scCO2 are experimentally investigated, and the dynamic process of scCO2-MQL penetration into the capillary is analyzed. The results show that under the applied experimental conditions, the injection temperature of scCO2-MQL ranges from approximately −45 °C to 60 °C. Because scCO2 presents good solubility in oil, it has the capacity to refine the oil droplets into smaller particles, thus resulting in a higher lubricating oil content in the capillary per unit of time. This leads to enhanced lubricity that can benefit processing applications. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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18 pages, 6322 KiB  
Article
Piecewise Decoupling Tool Orientation Re-Scheduling for Four-Axis Reciprocal Toolpaths of Blades Based on S-θ Plane with Monotonicity Constraint
by Jingsong Li, Dening Song, Peiyao Li, Qiang Zhang, Jinghua Li and Jianwei Ma
Machines 2022, 10(10), 953; https://doi.org/10.3390/machines10100953 - 19 Oct 2022
Viewed by 1330
Abstract
Reciprocal toolpaths with four-axis simultaneous motion of five-axis or four-axis machine tools are commonly used in the machining of blades which are widely applied in high-end equipment such as the aero-engine and the marine steam turbine. Due to the complex geometry of the [...] Read more.
Reciprocal toolpaths with four-axis simultaneous motion of five-axis or four-axis machine tools are commonly used in the machining of blades which are widely applied in high-end equipment such as the aero-engine and the marine steam turbine. Due to the complex geometry of the blades, the tool orientation always suffers from frequent swing for this kind of toolpaths, which induces unnecessary acceleration/deceleration of the feed axes, thus degrading processing efficiency and quality. Although there are tool orientation optimization methods aiming at solving the above problem, they are mainly proposed for universal processing of the toolpaths for complex surfaces. Different from them, this paper proposes a piecewise decoupling tool orientation re-scheduling method for this kind of toolpath specifically, which takes full use of the characteristic of the reciprocal toolpaths of the blades, and takes the monotonous variation of rotation axes as an additional constraint. The re-scheduling process is realized based on the construction of a S-θ plane, where the scheduling problem is converted to the adjustment of a S-θ curve inside a feasible channel. Through two procedures, namely linearization scheduling and control-point assigning-based smoothing, the tool orientation path expressed by the S-θ curve can be effectively scheduled in a piecewise manner, and the smoothness between two adjacent pieces of the toolpaths can be ensured directly. The whole algorithm is lightweight and does not involve complex iterative operations or functional optimization solutions. Simulation and experimental tests verify the feasibility and superiority of this method. The results show that the machining efficiency of the blade is improved by 24.5%, due to the reduction of the requirement on highest feed-axis kinematics parameters after rescheduling. In addition, compared with the existing methods, the proposed method not only can improve the dynamics of feed axes in multi-axis machining, but also has advantages in computational complexity and monotonic variation property of the tool orientation. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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Review

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19 pages, 3616 KiB  
Review
Recent Development for Ultra-Precision Macro–Micro Dual-Drive System: A Review
by Manzhi Yang, Haochen Gui, Chuanwei Zhang, Shuanfeng Zhao, Feiyan Han, Meng Dang and Bin Zhang
Machines 2023, 11(1), 96; https://doi.org/10.3390/machines11010096 - 11 Jan 2023
Cited by 7 | Viewed by 1974
Abstract
Macro–micro dual-drive technology uses a micro-drive system to compensate for motion errors of a macro-drive system, solving the contradiction between large travel and high-precision motion. Additionally, it has a wide range of applications in the ultra-precision field. Therefore, it is necessary to analyze [...] Read more.
Macro–micro dual-drive technology uses a micro-drive system to compensate for motion errors of a macro-drive system, solving the contradiction between large travel and high-precision motion. Additionally, it has a wide range of applications in the ultra-precision field. Therefore, it is necessary to analyze and research the ultra-precision macro–micro dual-drive system. Firstly, this paper analyzes the history of ultra-precision technology development and summarizes the research status of ultra-precision technology processing and application. Secondly, the micro-drive mechanism design and macro–micro-drive mode of macro–micro dual-drive technology, which can solve the contradiction of large stroke and high precision, are reviewed, and the application of macro–micro dual-drive technology in an ultra-precision system is summarized. Finally, the challenges and development trends of the ultra-precision macro–micro dual-drive system are analyzed. The research in this paper will play an important role in promoting the development of the ultra-precision system and macro–micro dual-drive technology. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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