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Tool design is very important in the modern manufacturing industry. However, the traditional tool design process often has a heavy workload, which reduces the production efficiency of tool manufacturing enterprises. To deal with these problems, this paper proposes an integrated tool design platform to solve the problems in tool design. The tool-integrated design platform uses parametric modeling technology to allow design engineers to quickly create a geometric model of the tool by setting key parameters. The platform also introduces cutting simulation technology. Design engineers can perform simulation analysis on the platform and evaluate its performance and feasibility by simulating different tool design schemes. At the same time, this paper also uses cloud database technology to realize the function of multi-person remote collaborative design. In addition, the platform also uses genetic algorithm to optimize the cutting depth, cutting width, feed rate, and spindle speed of the tool with the minimum three-way milling force as the goal to guide the actual processing and production. In summary, by introducing technologies such as parametric modeling, parametric simulation, and cloud databases, enterprises can effectively solve the problems in the tool design process. The design time cycle is greatly shortened, and multi-person remote collaborative design becomes more convenient. This will significantly improve the enterprise's production efficiency and help the tool's precise design. [ABSTRACT FROM AUTHOR]

Double-arc milling cutter can effectively enhance the workpiece surface quality and is appropriate for finish machining complex surface. This article examines the effects of tool structure factor, two vertical milling orientations, workpiece inclination angle, cutting speed, and feed per tooth on the cutting force in order to thoroughly explore the cutting performance of double-arc milling cutter. Instantaneous effective cutting speed and radius models are established for various cutting orientations and conditions using the parameterized model of double-arc milling cutter. Additionally, a method for characterizing the tool structure factor of double-arc milling cutter is proposed. Three double-arc milling cutters with different structure factor and single factor experiments for milling concave and convex surfaces are designed. The impact of tool structure factor, workpiece inclination angle, cutting orientations, and cutting parameters on cutting force is thoroughly analyzed. Theoretical support is provided for the optimization of tool parameters, cutting orientations, and cutting parameters prior to surface machining. [ABSTRACT FROM AUTHOR]

With the development of manufacturing fields such as automotive mold, the requirement for cutting tool with different structures and properties is constantly increasing. A parametric design method for double-arc milling cutter which is suitable for precision machining is proposed in this article. The tool rotation surface and cutting edge curves are provided. Effective cutting radius, cutting scallop-height, and curvature radius of tool surface are analyzed. The method for selecting tool parameters and feed direction is discussed. Five sets of double-arc milling cutters with different tool parameters are manufactured to verify the feasibility. An experiment is conducted to prove that machining quality can be improved by using double-arc milling cutter. This article provides a new method for tool parametric design and proposes a theoretical basis for better machining quality. [ABSTRACT FROM AUTHOR]

Aiming at the problems of uneven illumination at the edge of the surface damage image of the face milling cutter, the blade line at the damage cannot be accurately identified, and the slow recognition rate of the traditional image processing technology, an on-machine accurate measurement method for the surface damage of the face milling cutter, is proposed. The industrial camera, lens, and adjustable LED ring lighting are placed on the camera support, and they are used to collect the image of the flank face of the face milling cutter. This method first divides the tool damage area into the tool wear bright zone area and the damaged edge missing area and selects the specific tool position area for template matching. Next, the tool damage area is extracted, the arc fitting method is used to fit the missing area of the broken edge, the edge curve is reshaped, and the improved sub-pixel edge detection method is used to extract the lower boundary of the tool wear bright zone area. The cutting edge curve of the damaged area and the lower boundary edge curve of the wear area are spliced to obtain the tool damage area, and finally, the maximum damage width value of the tool flank is calculated. The on-machine detection platform is built to carry out the milling experiment of the face milling cutter. The damage value extracted by this method is compared with the damage value measured by the super depth of field microscope. The average difference in the tool damage value is within 3%. The results show that the proposed method can effectively detect tool damage under the premise of ensuring efficiency on-line and in-process and provides an effective solution for the condition monitoring of face milling cutter in actual machining. [ABSTRACT FROM AUTHOR]

Ball end mills have complex geometry. The precision CNC grinding of the cutting edge on the spherical surface is a big challenge for the tool manufacturers. Regarding the design cutting edge, we propose a cutting-edge design model in which the cutting edge can be offset along the spherical surface. To improve the accuracy of this model, the twist drill chisel-edge was also introduced into this design model of cutting edge. Then, referring to the toolpath calculation method of complex surface machining, we established a method for grinding the rake face of the ball end mill using a 1A1 standard wheel. For the clearance of the ball end mill, we developed a method to grind the clearance of the ball end mill using an 11V9 standard wheel. Finally, the design model of cutting edge, grinding models of rake face, and clearance were verified by simulations and experiments, respectively. The results show the proposed cutting-edge model has a better profile tolerance. The intersection line between the rake face and clearance coincides with the design's cutting edge. These prove the effectiveness of methods. [ABSTRACT FROM AUTHOR]

An increasing number of cutting tools with different geometric shapes are needed owing to the increasing complexity of the workpiece surfaces in aerospace and automotive molding. A new kind of milling cutter is designed, which is named as revolving lemniscate milling cutter (RLMC for short). The parametric mathematical models of RLMC are proposed. Mathematical models of cutting edge curves are proposed to provide the theoretical basis for RLMC precision manufacturing. Equivalent helix angle, curvature radius of tool rotation surface, effective cutting linear velocity, and scallop height are studied. Corresponding numerical simulation results are also provided as graphical representations. Three RLMC with different tool parameters are manufactured, and contrast experiments are conducted to prove that using RLMC in end milling can achieve better machining quality. The parametric design and application research provide a new method and theoretical basis for other new types of milling cutters. [ABSTRACT FROM AUTHOR]

There are inequable force-induced deformation, obvious cutting vibration problems during side milling of low-rigidity frame and beam parts, resulting in unsatisfactory dimensional accuracy and surface quality. Most of these parts are side-milled by end mill, which currently in use do not take into account the workpiece stiffness imparity. Therefore, the concept of gradient helix edge (GHE) is proposed in this research, and its advantages are analyzed. The general mathematical model is given. Furthermore, the parabola is taken as an example for the GHE space equation derived, of which accuracy is verified by numerical simulation. Finally, the comparison experiment with the invariant helix edge end mill was completed. The results showed that the milling force perpendicular to the milling surface of the GHE end mill was smaller and with less fluctuation, which could obtain less force-induced deformation theoretically. The milling process was smoother, and better surface quality was obtained. The excellent performance of the GHE end mill was further verified by milling different features. [ABSTRACT FROM AUTHOR]

The axial thermal error of five-axis CNC machine tools is a significant factor affecting the machining accuracy. To predict the axial thermal error during the machining process, a method is proposed to model axial thermal error in the machining space of five-axis machine tools with a double swing table. The comprehensive thermal error model of the machining space is first established, which includes the axial thermal error of the spindle, worktable, and other components. The spindle is then simplified as a rod, and an analytical model for the axial thermal error of the spindle is developed based on the heat transfer governing equations. This model enables the determination of the time-varying behavior of the axial thermal error at different speeds. Furthermore, the worktable is simplified as a circular plate, and the analytical model for the axial thermal error of the worktable is established based on the thermal bending differential equation of the small deflection circular plate. This model allows for the determination of the time-space variation of the axial thermal error at different radii of the worktable. Finally, based on the axial comprehensive thermal error field of the five-axis CNC machine tool processing space, the distribution of the axial thermal error in the machine tool processing space under thermal equilibrium conditions is revealed. Experimental verification of the proposed model is conducted on the VMC-C50 double swing five-axis CNC machine tool. The experimental results show that the error between the measured axial thermal error value and the axial comprehensive thermal error model value is within 26.6%, thus confirming the accuracy of the proposed model. [ABSTRACT FROM AUTHOR]

508-III steel has become one of the most viable materials for heavy nuclear reactor pressure vessels due to its excellent strength and fracture toughness. However, the poor machinability of 508-III steel requires the tool to withstand extremely high mechanical stress, thermal stress, and shock during the cutting process, thereby accelerating tool failure and affecting machining efficiency. High-feed milling (HFM) is a novel rough machining technology that ensures machining efficiency and prolongs tool life. This paper aims to reveal tool failure mechanisms during HFM of 508-III steel and to indirectly evaluate the cutting performance of the HFM cutter in the context of cutting vibration and chip morphology. Dry milling experiments of 508-III steel were carried out using an HFM cutter with arc-shaped bottom edges. Experimental results show adhesion, oxidation, and diffusion are the primary tool wear mechanisms. The wear levels between each insert present significant differences, which can be explained by cutting-edge position deviations and unexpected tool movements. With the continuous accumulation of tool wear, the insert with the weakest cutting edge strength is broken, which can be attributed to the crack propagation near the cutting edge, hard spots, and the shedding of adhesive materials. When the feed per tooth is 0.8~1.0 mm, the whole milling process shows good stability, especially in the spindle direction. The chip morphology and color variations are closely related to tool wear, which can provide an essential basis for tool failure prediction. [ABSTRACT FROM AUTHOR]

In the milling process of thin-walled parts, chatter is very easy to occur, which has a very adverse impact on the surface quality and machining efficiency of the workpiece. In order to solve the problem of low accuracy of milling state identification caused by few initial samples and dynamic changes in the milling process, a hybrid online evolutionary chatter identification model combining unsupervised learning and supervised learning was proposed. First of all, aiming at the problem that traditional K-means algorithm is difficult to adapt to online dynamic clustering of milling chatter, an online incremental-sparse K-means algorithm (ISK-Means) was proposed, and the dynamic incremental-sparse strategy of K-means was designed. Second, aiming at the problem that the online sequential extreme learning machine (OS-ELM) algorithm directly adds its predicted samples to the training sample set during the incremental learning process, and the pseudo-samples in the training sample set would lead to the degradation of the OS-ELM model, a hybrid online evolutionary chatter identification model combining the ISK-means and the OS-ELM was proposed, and the online identification and evolution strategy was designed. Finally, the experimental results show that the ISK-means algorithm can greatly improve the clustering efficiency and is suitable for milling chatter online dynamic clustering. Meanwhile, compared with the existing model, the recognition accuracy of the hybrid online evolutionary chatter recognition model combined with ISK-means algorithm and OS-ELM algorithm is improved by 1.31%. This is of great significance for the online control of subsequent chatter. [ABSTRACT FROM AUTHOR]

Machining-induced residual stress is an important measure of surface integrity. The residual stress affects the quality and performance of the workpiece. In the process of cutting, it often encounters the situation of multi-pass cutting. The formation of residual stress in the process of single- or multi-pass cutting has been widely studied, but few researchers consider the same total radial cut depth, divided into single-pass cutting and multi-pass cutting, and the last cutting in the process of multi-pass cutting is less studied. The difference between single-pass cutting and multi-pass cutting is that the former machining of cutting is used as the initial state of the latter machining. The stress/strain and temperature generated on the surface of the former machining can affect the subsequent cutting force, temperature, plastic deformation, and the final residual stress. This paper studies the distribution of cutting force and residual stress generated by single- and multi-pass cutting of Al-7075-T6, and focuses on the analysis of the multi-pass cutting strategy. The three-dimensional finite element method is used to simulate, and the experimental results are in good agreement with the simulation results. The results show that compared with single-pass cutting, multi-pass cutting can reduce the surface tensile stress and the magnitude and depth of underground residual compressive stress, and the effect of decreasing method is more obvious when multi-pass cutting. The last machining is affected by the previous cutting. When the next radial cutting depth is greater than the plastic deformation depth produced by the previous cutting, the next radial cutting depth is the same, and the trend of residual stress is approximately the same. The results can guide the optimization of residual stress in the multi-pass cutting strategy. [ABSTRACT FROM AUTHOR]

The machining residual stress generated on the surface of the machined parts during machining has a crucial influence on the machining accuracy, fatigue strength, and corrosion resistance of the parts. Tool wear will aggravate the tool-work friction, and the thermal and mechanical load will change significantly, affecting the residual stress distribution. The distribution of 3D oblique cutting mechanical stress and thermal stress during tool wear is predicted by analyzing the 3D contact state of quick oblique cutting. The incremental thermal-elastic–plastic method is used for stress loading, and the 3D relaxation method is used for stress release to obtain residual stress. An analytical residual stress model considering tool wear is proposed to predict the residual stress distribution in milling, while aluminum alloy 7075-T6 is used as the workpiece in the case study. The results show that with the increase of tool wear, the residual stress of machined surface transfers from compressive stress to tensile stress, the value of sub-surface residual compressive stress increases the peak value of compressive stress moves more resounding, and the thickness of residual stress layer increases significantly. The average error between the predicted and experimental values is about 23.3%, which proves the model's validity and provides a new idea for controlling the distribution of machining residual stress. [ABSTRACT FROM AUTHOR]

The secondary development can realize the integration of commercial CAD and CAM/CAE software and has been widely used in the design of cutting tools. However, with the development of cutting tools design towards system integration, the integration effect cannot meet the needs of current tool design due to factors such as kernel and interface. Based on the independent semi open source modeling kernel Open CASCADE, this paper realizes the parametric design of solid end mills. The parametric design system of solid end mills is established by using Python as the underlying language and Python OCC. The system can generate data files, 2D drawings, and 3D models conforming to ISO 13399 standard and realize the cloud storage function of model data. The generated tool model data can be used for finite element simulation of cutting process, NC programming, and guiding tool manufacturing. Based on the established system, the centroid optimization of the imbalance characteristics of the variable pitch and variable helix end mill is carried out, which improves the dynamic balance of this type of cutter and provides an important reference value for the design of this type of cutter. [ABSTRACT FROM AUTHOR]

Corner is one of the typical characteristics of aerospace monolithic components. In order to achieve a stable processing environment and reduce the mutation of milling force in the process of machining, the manufacturer has been searching a method to control the milling force of corner machining. Based on the cutting contact relationship and the instantaneous chip thickness, the milling force prediction model of corner machining is established. By analyzing different types of corner contact relationship, the influence of cutting contact angle and cutting arc length on milling force is established. The corner feed rate iterative calculation method is used to improve the corner milling force mutation. The corner milling experiment proves that the proposed method can not only effectively control the corner milling force, but also improve the surface quality of the bottom surface of the workpiece. The proposed method is suitable for automatic programming of multi-corner pocket machining and provides theoretical support for stable machining of frame part. [ABSTRACT FROM AUTHOR]

Conical end milling cutter is used more and more widely in NC machining. The flute is an important feature of the milling cutter, which directly affects the cutting performance of the milling cutter. However, the conical flute belongs to a complex spatial helix surface. In the machining process, the relative motion of the wheel and milling cutter is complex. To solve this problem, this paper presents a trajectory calculation method for grinding the flute of conical milling cutters. Firstly, the conical cutting edge line is deduced, and the position of the wheel in the whole grinding process is calculated under the design requirements of the rake angle and the core radius. Secondly, a method for calculating the flute profile of complex flutes is given. Finally, the effectiveness of this method is verified by numerical simulation, and it can also be extended to more complex flute grinding in future research. [ABSTRACT FROM AUTHOR]

Chatter is a kind of self-excited vibration that often occurs in the milling process of thin-walled parts, which has become the main factor restricting production efficiency and quality. Due to the occurrence of chatter, the signal becomes more complex and unstable. In order to realize milling chatter detection of thin-walled parts, the method of multi-sensor signal fusion is used. A chatter detection method based on variational mode decomposition (VMD) and nonlinear dimensionless index is proposed by analyzing the characteristics of signals in time–frequency domain. Firstly, a series of intrinsic mode function (IMF) components are obtained by decomposing force and acceleration signals with VMD. When chatter occurs, the energy is transferred to the chatter frequency band. Each IMF signal's nonlinear energy entropy (EE) is extracted to construct the feature vector. A support vector machine chatter identification model based on multi-sensor signal fusion is established. To solve the problem of model incremental updating, supervised learning and unsupervised learning are combined to provide a method for chatter detection. [ABSTRACT FROM AUTHOR]

Tool wear detection based on machine vision is the core to realize intelligent and automated cutting processing. It is essential to solve the problem of low-efficiency and low-quality acquisition of tool wear image acquisition in the machine detection process. In this paper, the image acquisition method by using a 6-DOF (degree of freedom) serial robot with an industrial camera is developed. The digital twin unit of the detection system is set up, the UR10 robot kinematics model and acquisition trajectory planning method are proposed, and Unity3D software is used to arrange the digital twin environment of the detection system. The synchronous mapping function of the robot digital model and physical entity is given through Socket communication to realize complex tool edges image acquisition trajectory planning, accurate teaching of virtual scenes, digital monitoring of the detection process, and optimization of system models. The stability and efficiency of robot kinematics, trajectory planning, and interactive communication in the tool wear image detection environment are verified. The research results show that the proposed method can provide support for the digital monitoring and control technology of the tool wear on-machine detection process. [ABSTRACT FROM AUTHOR]

The flute plays an important role in the design process for tools. The complexity of the cutting edge is increasing continuously. Thus, it is difficult to grind flute precisely and efficiently. This paper presents a practical grinding method for the flute of tools. It solves the issue of how to grind the flute with the complex edge by standard wheels. It is summarized as follows: the curve of cutting edge and core are used as the designed parameters of the flute; we propose the fundamental conditions that the wheel does not interfere with designed parameters; we can find the posture and position of wheel in the curve frame easily, thus obtaining wheel trajectory. Finally, using a taper end mill as an example, the results show a good agreement between the CAM data and the model data. This proves the effectiveness of this method. [ABSTRACT FROM AUTHOR]

In the milling process, it is easy to produce chatter due to the low rigidity of the thin-walled structure, which leads to the deterioration of workpiece surface quality and reduces the service life of cutting tools and machine tools. Therefore, a new chatter detection method for thin-walled parts based on optimal variational mode decomposition (OVMD) and refined composite multi-scale dispersion entropy (RCMDE) is proposed in this paper. Firstly, to solve the problem that the decomposition effect of the variational mode decomposition (VMD) algorithm is greatly affected by its parameter, a genetic algorithm (GA) is used to iteratively optimize the parameter of the VMD algorithm, and a new index, square envelope spectral correlated kurtosis (SE-SCK), is introduced as the fitness function of the genetic algorithm. Then, the energy ratio of the decomposed signal is calculated as the principle of selecting sub-components, and the sub-components with rich chatter information are selected for signal reconstruction. To solve the problem that the multi-scale dispersion entropy (MDE) will miss some information in the multi-scale process, RCMDE is introduced to detect milling chatter. Finally, the experiment of the variable cutting depth in side milling of titanium alloy thin-walled parts is carried out. The experimental results show that the OVMD algorithm proposed can solve the problem of difficult separation of chatter frequency bands caused by mode aliasing and lay a foundation for subsequent chatter feature extraction. RCMDE is more conducive to chatter detection than the single-scale DE when the scale factor is 4. The distinguishing effect of RCMDE on the machining state is more than 50% higher than that of MDE when the scale factor is 4. [ABSTRACT FROM AUTHOR]

The performance of metal cutting tools directly affects the manufacturing efficiency and machining quality of products. With the increasing demands in manufacturing industry of cutting performance, machining efficiency, customization, and quick response, traditional tool design methods can no longer meet the above requirements due to many repetitive work, large amount of calculation, complex process, and low efficiency. Parametric design has become a new development direction of customized tool design because of its fast, stable, and accurate characteristics. Based on the parametric design of cutting tools, this paper develops a tool parametric design platform by using the method of secondary development of commercial CAD software. The platform realizes automatic operation in the background without commercial CAD software interface, completes the parametric modeling process of tools, generates 2D drawings and 3D models conforming to ISO 13399 standard, and realizes the cloud storage function of model data and the parametric design of many kinds of tools. Compare with that traditional modeling method, using this parametric modeling platform, the modeling efficiency is increased by 90% on average. This platform is of great significance to improve the design efficiency of complex customized tools and shorten the original design cycle by 30%. [ABSTRACT FROM AUTHOR]

The geometric error of a machine tool is the main factor influencing its accuracy. Studying the sensitivity of various geometric errors of machine tools can provide a certain theoretical basis for analyzing their accuracy. In this study, first, based on the theory of a multi-body system, the spatial geometric error model of a two-turntable five-axis machine tool is established. In addition, the geometric errors E x , E y , and E z in the X, Y, and Z directions, respectively, and the spatial composite error E p of the machine tool are obtained. Then, based on the function differential method, the sensitivity expression of each error of the machine tool is identified. Finally, two S-shaped specimens with different angles of surface inclination are used as processing objects for experimental verification. The composite errors of the S-shaped specimens are measured and the sensitivity of their geometric errors is calculated. The results show that six geometric errors, namely angular displacement error of A axis along X direction ε x A , angular displacement error of A axis along Y direction ε y A , angular displacement error of A axis along Z direction ε z A , angular displacement error of C axis along Y direction ε y C , angular displacement error of C axis along Z direction ε z C , and angular displacement error of C axis along X direction ε x C , have a strong influence on the composite errors of machine tools. They account for more than 50% of all geometric errors, and the sum of their sensitivities is 0.526. It can be concluded that reducing and compensating the rotation errors of the two rotating axes of a machine tool can significantly improve its machining accuracy. [ABSTRACT FROM AUTHOR]

Saving resources and reducing the energy consumption of CNC machine tools has become one of the main research directions of modern green manufacturing. In this paper, the influence of curvature characteristics on energy consumption is studied based on surface milling. Firstly, the loss of energy consumption in the machining process of the NC machine tool is analyzed, and the milling energy consumption model per unit volume is established; secondly, based on the unit volume milling energy consumption model, a unit volume milling energy consumption model considering blade curvature characteristics is established; finally, based on the milling energy consumption model, the "specific energy" is introduced to establish the energy consumption field model of blade milling path. The distribution of the energy consumption field of four milling paths is analyzed in turn, and the distribution of the energy consumption field of 24 tool sites in the milling path is analyzed. The experimental results show that the energy consumption field model can show the energy consumption distribution of the NC machine tool machining process, and the accuracy is more than 90%, which provides a reliable basis for the subsequent energy consumption prediction of the impeller machining process. [ABSTRACT FROM AUTHOR]

In the big data era, traditional data mining technology cannot meet the requirements of massive data processing with the background of intelligent manufacturing. Aiming at insufficient computing power and low efficiency in mining process, this paper proposes a improved K-means clustering algorithm based on the concept of distributed clustering in cloud computing environment. The improved algorithm (T.K-means) is combined with MapReduce computing framework of Hadoop platform to realize parallel computing, so as to perform processing tasks of massive data. In order to verify the practical performance of T.K-means algorithm, taking machining data of milling Ti-6Al-4V alloy as the mining object. The mapping relationship among cutting parameters, surface roughness, and material removal rate is mined, and the optimized value for cutting parameters is obtained. The results show that T.K-means algorithm can be used to mine the optimal cutting parameters, so that the best surface roughness can be obtained in milling Ti-6Al-4V titanium alloy. [ABSTRACT FROM AUTHOR]

Due to its good cutting performance in titanium alloy machining, integral end mills are more and more used in machining aero-engine impeller blades. The tool spiral groove plays the role of chip acceptor and chip removal, and the accuracy of its parameters has an important effect on the cutting performance. In the grinding process of the spiral groove, the grinding wheel's external grinding is mainly involved in the grinding task. The grinding wheel's wear degree is related to the grinding time and grinding times of the grinding wheel, and the wear of the grinding wheel will lead to the change of the parameters of the spiral groove. To achieve the accurate solution of the grinding wheel surface wear profile, image processing technology was used to extract the spiral groove end section contour coordinates of the grinding wheel and fit them. The worn sand profile was solved based on the contact line principle, and the grinding wheel wear amount was obtained. The traditional reconstruction method was used to verify the algorithm. The results show that the accuracy of the reverse algorithm for the wear profile of the grinding wheel is relatively high. [ABSTRACT FROM AUTHOR]

Studies show that the applied torque and load on the worktable of a dual-turntable five-axis machine tool continuously change during the machining process. These variations generate vibration in the worktable along the axial direction, thereby reducing the machining accuracy. In order to improve the machining accuracy of the machine tool and the dynamic characteristics of the worktable, this paper first established the nonlinear dynamic equation of the axial vibration of the machine tool table when the worktable is subjected to torque, swing moment, and load according to the elasticity of the plate and shell, then according to Galerkin, the truncation method solves the dynamic displacement in the axial direction of the worktable, as well as the bifurcation diagram, displacement waveform diagram, phase plane trajectory, and Poincarn method solvon diagram of the processing system. Finally, the influence of different parameters, including torque, swing moment, and load on axial vibration of the worktable was analyzed during the tool operation. The obtained results reveal that as the external load changes, the corresponding axial vibration of the worktable is mainly in the state of large periodic motion, where the maximum vibration amplitude reaches 0.09 mm, and the external load has the greatest influence on the axial vibration of the worktable. Moreover, the axial vibration of the worktable is affected by the swing moment. More specifically, in the chaotic state of a small period and small area, the maximum vibration amplitude reaches 0.03 mm, and the swing moment has a negligible effect on the axial vibration of the worktable. The influence of torque and load on the vibration characteristics of the five-axis machine tool table during machining was studied through experiments. The obtained results demonstrate that nonlinear analysis of the table axial vibration of the five-axis machine tool with dual turntables is an effective way to control the stability of the worktable during the processing of the workpiece. [ABSTRACT FROM AUTHOR]

Generally, off-line methods are used for surface roughness prediction of titanium alloy milling. However, studies show that these methods have poor prediction accuracy. In order to resolve this shortcoming, a prediction method based on Cloudera's Distribution including Apache Hadoop (CDH) platform is proposed in the present study. In this regard, data analysis and process platform are designed based on the CDH, which can upload, calculate, and store data in real time. Then this platform is combined with the Harris hawk optimization (HHO) algorithm and pattern search strategy, and an improved Harris hawk optimization optimization (IHHO) method is proposed accordingly. Then this method is applied to optimize the support vector machine (SVM) algorithm and predict the surface roughness in the CDH platform. The obtained results show that the prediction accuracy of IHHO method reaches 95%, which is higher than the conventional methods of SVM, BAT-SVM, gray wolf optimizer (GWO-SVM), and whale optimization algorithm (WOA-SVM). [ABSTRACT FROM AUTHOR]

The cutting process of titanium alloy Ti-6Al-4 V is a complex thermomechanical coupling process with high temperature and high strain rate. In this paper, the modified Johnson–Cook (JCM) constitutive model considering strain-temperature coupling and high temperature dynamic crystallization is established, and the modified JC constitutive model is compiled based on the user subroutine VUMAT of ABAQUS. The 3D milling finite element simulation model of titanium alloy frame thin-walled parts is established, and the stress field, temperature field, milling force, and workpiece deformation are simulated and analyzed. The results show that the modified JC constitutive model improves the simulation accuracy by 4.3% and can more accurately describe the mechanical behavior of Ti-6Al-4 V alloy thin-walled parts in the cutting process. [ABSTRACT FROM AUTHOR]

Ball-end cutters are widely used in industries of dies, molds, and aerospace, which have the problem of poor machined surface quality due to the low cutting speed near the tool-tip. With the increase in the complexity of parts, it will become more and more difficult to avoid the tool-tip participating in the cutting. In this paper, the velocity effect sensitivity of the ball-end cutter is analyzed, and several key positions, including the intersection points of the CWE boundaries, are selected to describe the cutting speed in three dimensions. The relationships between the cutting speed of the critical points and important variables such as the machining inclination angle and the feed direction were investigated. The optimal range of feed direction is obtained when the tool-tip engages in the contact circle. The core aim of the feed direction selection is to make the tool engagement area in a high position by changing the feed direction, to avoid surface damage and improve the quality of the machined surface. Finally, an experimental study was carried out, and the results corroborate the effectiveness of the selection method. In the experiment, it was also found that cutting-out from the cutter contact position can improve the surface quality in the directions of non-optimal range, and the milling force and chips shape will vary with the change of the feed direction. [ABSTRACT FROM AUTHOR]

In order to study the correlation between parameters and performance indicators in the cutting process, the importance of different parameters in performance indicators should be determined. In the present study, the side milling process of titanium alloy by the end milling cutter is considered the research object, and analytic hierarchy process and grey-fuzzy evaluation method are used to evaluate the importance of tool geometric parameters and operating parameters on tool wear rate and material removal rate obtained by FEM method. It is found that applying the average method to remove the parameter level makes each parameter achieve the same result. Therefore, this method should be combined with other data processing methods to resolve the above problem. Finally, the range analysis method is applied to obtain the optimal parameter level of different parameters for each performance indicator. The obtained results show that the helix angle has the highest overall importance value, followed by feed per tooth. And the optimum combination of parameters for tool wear rate and material removal rate is obtained respectively. [ABSTRACT FROM AUTHOR]

Titanium alloy Ti6Al4V has the advantages of high specific strength, good heat resistance, and strong corrosion resistance, which is widely used in the manufacturing of aerospace industrial parts. However, in the side milling of titanium alloy, the temperature of the cutting area is high, and the cutting edge position is prone to breakage, which affects the surface quality of the workpiece. In order to reveal the tool damage failure mechanism in the milling process of titanium alloy, firstly, the impact force model when the tool cuts into the workpiece from the empty stroke and the milling force model during milling are established to obtain the cyclic load characteristics and impact effect of the tool. Then, based on the fatigue crack propagation theory and the energy balance equation of sliding crack, the elastic modulus and crack propagation law of tool material under different cutting impacts are analyzed. The interval method is used to recalculate the initial and critical damage value of tool material fracture in the maximum range. Finally, the limit conditions of the edge impact fracture of the end mill are established, and the safe cutting area of tool breakage is redefined. Through the milling test of titanium alloy, the impact damage morphology of tool in different states is redefined. The obtained redefined tool safety area provides a theoretical basis for high-speed and high-efficiency milling of titanium alloy, tool breakage, and tool life. [ABSTRACT FROM AUTHOR]

In the milling process, chatter is easy to occur and has a very adverse impact on the quality of the workpiece and the production efficiency. A chatter feature extraction method based on optimized variational mode decomposition (OVMD) and multi-scale permutation entropy (MPE) was proposed to solve the problem that it is difficult to detect the machining chatter state during milling. The methodology presented in this article allows the occurrence of machining chatter to be effectively identified through real-time digital signal processing and analysis. First, in order to solve the problem of variational mode decomposition (VMD) parameter selection, an automatic selection method based on particle swarm optimization (PSO) and the maximum crest factor of the envelope spectrum (CE) was proposed. Then, the decomposed signal was reconstructed based on the energy ratio. In order to solve the problem that the single-scale permutation entropy (PE) cannot detect milling chatter well, the MPE was introduced to detect milling chatter. Finally, experimental verification was carried out, and the MPE of the reconstructed signals at different scales was extracted and analyzed. The results show that using the OVMD algorithm to process the signals can significantly improve the discrimination of MPE. With the increase of the scale factor, the MPE of the milling signals tends to decrease. At the same time, MPE is better than single-scale PE in chatter detection, and the MPE at scale factor of 4 is more conducive to chatter detection. [ABSTRACT FROM AUTHOR]

Solid end mill cutting tools are widely used in machining of curved surface parts in many industrial sectors, e.g., aerospace, automotive, and energy. Grinding is one of the most important processes in the manufacturing of the tools, and the movement of the grinding wheel closely influences the key parameters of helical groove cross-section, i.e., rake angle γo, inner core radius Rc, outer core radius Rcb, and edge width Ew, as well as chip removal capacity. However, a "closed" flute of a tool, which is one style of flute, may cause many problems if grinding it by one-pass, e.g., grinding wheel dressing to adapt to the change of flute parameters. To solve the problem in "closed" flute grinding, this paper proposes a two-pass flute grinding based on the iteration method. Within the context, some parameters and rules are identified in modeling of the two-pass grinding to control grinding wheel width and to smoothen grinding marks between the two passes of grinding. Finally, the method is implemented and validated by a set of numeric simulations and experiments. The results show that the errors of core radius, rake angle, edge width, and big core radius of the two ground tools are 1.1%, 2.0%, 3.4%, and 2.2%, respectively, which are within the designed tolerances. [ABSTRACT FROM AUTHOR]

The quality of a workpiece depends on the time-varying characteristics of the tool performance. Tool wear is an important factor that affects the serviceability of a tool. However, most existing models do not fully contain the tool design and processing parameters and do not focus on the time-varying characteristics of wear. In this paper, the wear distribution characteristics of a ball-end mill were investigated by analysing the position function in the milling life model, and the geometric model of the wear volume was proposed based on the principle of calculus. By geometric and physical modelling, the tool design and machining parameters were completely introduced in the model, and the time variable is introduced when solving the wear rate. After the models and assumptions are validated, the factors affecting wear are cross-analysed and discussed through simulation. Wear models including time variables, tool design, and milling parameters are obtained, which can be used directly for tool design and analysis. This research provides a basis for the tool analytical design. [ABSTRACT FROM AUTHOR]

Deformation is an unavoidable phenomenon in a thin-walled milling operation, which causes the radial cutting depth to deviate from the initial position and change the tool-workpiece meshing boundary. Milling force is an important factor in the deformation; thus, the phenomenon of machining deformation mechanism is revealed and a machining error prediction model based on the force-deformation coupling relationship is developed in this paper. Discrete micro-cutting disks of the thin-walled parts take into account the deformations and milling cutting force of different contact relationships in the cutting area. The tool-workpiece contact relationship (single-flute cutting and double-flute cutting) is determined by different cutting parameters and the deflection of thin-walled parts is introduced. A detail iterative strategy is developed to calculate the milling force after deformation and the tool-workpiece meshing boundary. By modifying the instantaneous chip thickness of each micro-cutting disk, a new force-deformation coupling relationship and a time-based deformation matrix of different contact relationships are obtained. The machining error is calculated by considering the part deformation and the surface generation mechanism. After finishing systematic experiments, a comprehensive comparison between the model in mechanical prediction and experiments proves that the model captures the material removal mechanism that produces machining error. The results show that the proposed method can effectively predict the machining error. [ABSTRACT FROM AUTHOR]

Solid cutting tool is more and more widely used, such as aerospace, automobile and 3C. Helical groove is an important feature which influences the performance of solid cutting tool. Furthermore, groove grinding is the longest and largest material removal process in whole grinding of solid tool. Therefore, the most wear of grinding wheel occurs in its grinding. The worn wheel would result in groove grinding error without a proper compensation. The traditional compensation relies on the experience of machine operator, and generally, it is performed on site. In this paper, a compensation algorithm of worn wheel is proposed by analysing the boundary contact condition which is influenced by wheel wear. Furthermore, the algorithm is implemented by using C# and validated by a set of and experiments. The experimental results show that the ground tool flutes under compensation algorithm are controlled within designed tolerances; i.e., core radius errors are 1.7% and 0.7%, rake angle errors are 1.5% and 0.6%, and edge width errors are 4.3% and 5%. [ABSTRACT FROM AUTHOR]

The tool radial runout effect in milling process has a significant impact on milling mechanics and dynamics, which increases the difficulty of accurate characterization of milling process. According to the cutter-workpiece contact relationship, the instantaneous chip thickness model considering the tool radial runout effect is established, and the prediction model of plunge milling force is obtained by combining the instant rigidity force model. The dynamical model with three degrees of freedom is established according to the characteristics of plunge milling and the time-varying delay effect caused by tool radial runout. The stability lobe diagram of the plunge milling process is obtained by the improved semi-discrete method. The simulation results are in good agreement with the experimental results, which verify the correctness of the model. The results show that the tool radial runout effect can improve the milling stability in a certain speed range. The effect of the tool radial runout on bifurcation frequency is also studied. It is found that the tool radial runout effect can produce period 1 bifurcation frequency in the milling non-stationary process and double the period 2 bifurcation and Hopf bifurcation frequency. The research results can provide theoretical support for accurate characterization and optimization of process parameters in plunge milling process. [ABSTRACT FROM AUTHOR]

In order to meet the requirements of green, high-efficiency, and high-quality hole-machining in carbon fiber reinforced polymer (CFRP), firstly, this work introduces the suction-type internal-chip-removal system, which could discharge the chips formed in the CFRP drilling process in a timely and efficient manner. And based on the system working principle, the design basis of the inner flow channel of the suction-type internal-chip-removal drill system is provided. Secondly, we studied the influence of the PCD drill structural parameters on the drilling force by experiment and obtain the conclusion that the drilling force will be increasing when the front angel is getting larger under the drilling parameters of n = 3000r/min and f = 200mm/min; however, it increased slowly when the front angel (γ1) is in the range of 118 ° ≤ γ1 < 130°. Meanwhile, with the increase of the rear angle (α), the drilling force increases first and then decreases. Then, based on the research results above and combined with experiment and simulation of ABAQUS User subroutine to define material behavior (VUMAT), we completed the design of PCD double-peak angel blade for suction-type internal-chip-removal drill. Finally, we manufactured the drill for suction-type internal-chip-removal system, verified the accuracy of the design by experiment comparison, and researched the influence of chip-removal negative pressure on drilling defect. [ABSTRACT FROM AUTHOR]

The anisotropy characteristic of carbon fiber reinforced plastic (CFRP) easily results in defects such as delamination, tear, and burr in the milling procedure, which seriously restrict its widespread application. Thus this work conducted an experimental research in the cutting performance of the diamond-coated rhombic milling cutter in machining carbon fiber composites. Tool wear procedure and wear mechanism were analyzed, and the variation of both surface quality and cutting force under different tool wear conditions were obtained. It was found that the tool wear process can be divided into two stages, that is, coating wear dominated by abrasive wear and coating shedding by fatigue wear mechanism. In the stage of coating wear, the machined surface of carbon fiber composites was flat and regular, and chips were mainly granular. Whereas in the stage of coating shedding, cutting forces increased substantially; some defects such as stratification, tearing, and fiber pull-out got to occur on the machined surface, and lots of burrs were produced at the edge of machined surface. And here chips were a blend of granular and long-strip ones. The analysis of tool wear mechanism and machined surface morphology in machining carbon fiber composites can provide a significant theoretical reference to improving the machining quality of carbon fiber composites. [ABSTRACT FROM AUTHOR]

Targeting energy-efficient machining process planning, this paper presents a follow-up research on cutting energy consumption modelling for prismatic machining features (PMFs). Based on the investigation of plastic deformation-based energy consumption, its energy consumption model is extended to PMFs by refining machining time and feed at corners. Material removal volume associated with machining strategies for the PMF machining is considered as well. Moreover, cutting energy consumption models are established for the selected PMFs, i.e. face, step, slot and pocket. Finally, energy consumptions in machining of a designed test part, involving the established models of cutting energy consumption for the selected PMFs, are measured and compared with estimated energy consumptions to validate the developed models. [ABSTRACT FROM AUTHOR]

In the milling process of titanium alloy thin-walled parts, because of its low stiffness, processing deformation easily occurs, which results in in low-dimensional accuracy of machined surface and affecting the workpiece performance. Cutting force is the main factor that causes cutting deformation. Cutting deformation also affects cutting force. There is a coupling relationship between them. To solve the above problems, a method is proposed to predict the surface error by calculating the milling force by varying the chip thickness and by coupling the force with the elastic deformation of the workpiece. Firstly, the analytical model of bending elasticity deformation of thin-walled parts is established. Then, the micro-unit entrance angle and instantaneous chip thickness are calculated by the contact relationship of workpiece deformation and the chip boundary decision conditions. The cutting force and workpiece deformation at random rotating angle are obtained by iterative calculation method. Finally, the surface error is predicted by calculating the deformation matrix and the principle of surface generation mechanism. The simulation results are in good agreement with the experimental results, which verifies the accuracy of the proposed method. The results provide theoretical support for milling process optimization and profile accuracy control of titanium alloy thin-walled parts. [ABSTRACT FROM AUTHOR]

This paper presents a novel grinding enabled texture, ‘V’ shaped texture (VST), on flank face. To implement the texture on a cutting performance, a set of chamfering experiments of stainless steel materials used as 3C product shell usually are presented. Cutting forces, surface qualities, and tool wear are measured and compared, of which results show that both smallest surface roughness and longest tool life are achieved by using a 30° VST chamfer tool. By comparing the results, a clear conclusion can be drawn that texture types and angles are not independent factors to cutting performance; therefore, a suitable combination of texture types and texture angles can provide a significant improvement of tool life and surface quality. [ABSTRACT FROM AUTHOR]

In the process of boring and trepanning association (BTA) deep hole drilling, the guide block plays the role of guiding, balancing the cutting force and extruding and polishing the machined surface. In this paper, the trapezoidal guide block and the spiral guide block are designed on the basis of ordinary guide block. With simulation and experiment, the cutting force, cutting vibration, and cutting temperature of guide blocks of different shapes during drilling process have been analyzed. When the spiral guide block deep hole drilling is compared with ordinary and trapezoidal guide blocks, it ensures effective cutting performance of BTA deep hole drilling. It also improves the quality of machined surface of the workpiece, reduces the tool wear, and forms stable chips. [ABSTRACT FROM AUTHOR]

In deep hole boring process, long and flexible boring bars are often used. Due to the large length-to-diameter ratio, the stiffness of the boring bars is inevitably reduced, where the boring bars’ vibration effects will occur. The influences of vibration will significantly degrade the accuracy and the surface quality, or even lead failure of the production. Therefore, it is of significant importance to develop techniques to reduce vibration in deep hole boring. In this paper, a new boring bar with a variable stiffness dynamic vibration absorber (VSDVA) is presented, where the basic parameters of the proposed boring bar are measured. Based on the proposed dynamic model, the vibration characteristics of the proposed boring bar are analyzed, and the change laws of the vibration reduction performance are obtained under different excitation frequencies. A new vibration reduction method is proposed, where best vibration reduction performance can be achieved by adjusting the stiffness of the VSDVA. Finally, the vibration reduction performance of the proposed boring bar is validated and evaluated by boring experiments. These works could provide guidance for designing new types of boring bars, selecting cutting parameters, and adjusting the vibration reduction performance of the proposed boring bar, and as a result, it provides a new design idea for the design of boring bar. [ABSTRACT FROM AUTHOR]

Thanks to its good specific strength and modulus, carbon fiber-reinforced plastic (CFRP) is widely used in such fields as aerospace and automotive. Nonetheless, it is very likely that the serious tool wear and some surface quality defects occur in machining, such as delamination, tear, burr, and so forth. Thus, this paper carried out the experimental research into the tool wear in milling carbon fiber composites with spiral staggered diamond-coated milling cutter. According to the evolution of tool wear micro-morphology, the tool wear process was obviously divided into two stages, i.e., coating particle wear and coating shedding. It was found that the former was dominated by the abrasive wear mechanism and the latter the fatigue wear mechanism. In addition, wear mechanism and cutting force variation of each stage were analyzed. In addition, the coating shedding happened obviously in advance with the increase of milling speed. In the period of coating particle wear, the tool was in good cutting performance, and its cutting force changed slowly, while after it came into coating shedding period with the aggravation of tool wear, the cutting force increased greatly and the cutting performance worsened obviously. Thus, the appropriate control over the tool wear of spiral staggered diamond-coated milling cutter is the key to improving the machining quality of carbon fiber composites. [ABSTRACT FROM AUTHOR]

In the milling process of automobile panel mold of hardened steel, the characteristic of free-form surface is one of the dominant factors for surface topography. In this paper, the trajectory of cutting edge is firstly modeled to analyze the residual height of the free-form surface in ball-end milling of hardened steel. Furthermore, the non-uniform rational B-splines (NURBS) surface reconstruction is utilized to generate the surface topography. Subsequently, the influences of surface curvature, lead angle, milling vibrations on the machined surface topography, and residual height are investigated, respectively. Finally, the accuracy of the surface topography and the roughness prediction model are validated by the milling experiments of free-form surface, where two-dimensional contour maps could be obtained. The simulation and experimental results demonstrate that the machined surface topography of hardened steel is fitted by means of NURBS surface reconstruction. In that manner, the effects of surface characteristics on the machined surface topography can be accurately predicted. [ABSTRACT FROM AUTHOR]

The cutting edge structure of PCBN tools has an important influence on cutting force, chip morphology, and tool wear in hard cutting process. In order to evaluate the cutting performance of PCBN tools with variable chamfered edge, this paper carried out comparative experiments of high-speed hard cutting hardened steel GCr15 by PCBN tools, respectively, with variable chamfered edge and uniform chamfered edge, and proposed the detection index and measurement of macroscopic and microscopic morphological characteristics of chips, and found the variation rule of cutting force, chip morphology, and tool wear over cutting time. The experimental results showed that under the effect of helical cutting edge, the axial and radial load of the PCBN with variable chamfered edge, to a certain extent, was decomposed, which resulted in relatively smaller radial force and axial force; in the state of no tool wear, the macro morphologies of chips generated by the two cutting tools with different chamfered edges, were both wavy, however, with the increase of cutting time, the chip morphology of the cutting tool with uniform chamfered edge changed from being wavy into being irregularly curved, while the one of the cutting tool with variable chamfered edge remained invariable. In contrast, as for the cutting tool with variable chamfered edge, the margin of its rake crater wear is relatively far away from the cutting edge, and it has obvious advantages in improving the chip removal performance and tool life, and reducing the cutting resistance. [ABSTRACT FROM AUTHOR]

Belt sanding is an effective manner of material processing and widely used to improve the surface roughness and obtain high polishing glossiness. During the belt sanding process, the contact condition exhibits more complexity than grinding due to the flexibility of the belt. For the sanding application where surface glossiness is expected, it always involves multiple sanding as well as polishing passes. This makes the analytical modeling of the surface generation as well as its impact on glossiness formation complicated in this multi-pass operation. In this paper, the surface generation model for multi-pass sanding operation is established through the development of the virtual sanding belt model and the multi-pass kinematics simulation of the sanding process. As for the belt-workpiece contact zone, the 3D Hertz contact model is incorporated into the kinematics simulation to duplicate the real contact condition for multi-pass sanding. Furthermore, the critical surface topography parameters are identified to establish the correlation with belt sanding parameters. Finally, surface topography parameters related with glossiness properties, e.g., surface roughness Sq, surface height distribution kurtosis Ku, surface height distribution skewness Sk, and surface correlation lengths Lx and Ly, are studied for optimal sanding process parameter analysis. The optimal sanding condition for ideal glossiness should be that the rotation speed should be beyond 1200 r/min, and the workpiece feedrate should be below 50 mm/s. [ABSTRACT FROM AUTHOR]

The cutting force signal distortion is caused by the dynamic characteristics of cutting force testing system. In order to handle this issue, we propose two improvements in the traditional inverse filtering technology. Firstly, we use three-spline interpolation method instead of the curve fitting method to fit the frequency response function of the test system which basically improves the accuracy of fitting. Secondly, the low-pass filter is added before the inverse filter to eliminate the influence of the high-frequency noise signal on the cutting force signal. We choose the cavity-free surface of outer covering parts of mold of automobile as research objects. The inverse filter dynamic compensation technology has been used to remove the influence of the dynamic characteristics of the test system and the high-frequency noise on the cutting force signal. The effectiveness of the proposed method is verified by relative milling experiments. Based on the experimentally measured forces after dynamic compensation, the modified cutting force coefficients are obtained using the average milling force method. The variation law of the cutting force coefficients with the axial depth, the radial width, and the feed rate is examined. Based on the modified variable cutting force coefficients, the 3D stability of the ball end milling cutter surface has been obtained using full-discretization approach. Combining the results from the cutting experiment and the nonlinear method, the stability prediction based on the modified variable cutting force coefficient can improve the prediction accuracy. The results provide theoretical support for the optimization of the machining process of the cavity-free surface of outer covering parts of mold of automobile. [ABSTRACT FROM AUTHOR]

In order to tackle the problems during processing titanium alloys, 2D orthogonal cutting mechanics models are proposed in this paper. In particular, models are based on the classical orthogonal force model with the consideration of the blunt tool edge and the chamfering tool edge when the force is less than the tool edge radius. Moreover, simulations and experiments have been carried out to investigate the characteristic of forces of the tool edge. The model describes the relationship between the tool edge and forces. In addition, it can accurately predict the initial flow of the chip under the action of the tool edge. Substantially, the theoretical basis for optimizing the design of the tool edge can be provided. [ABSTRACT FROM AUTHOR]

To predict energy consumption in machining, a mathematical modelling method to mimic the cutting energy consumption during machining is proposed in this paper. The established model is based on the law of energy conservation. The mechanical material property coefficients and cutting parameters are included in the model by using material deformation theory and friction calculation which are used to represent the phenomena in machining. Cutting energy of material removal process is refined by analysing the effect of tool edge geometry. In addition, the machining process is divided into two machining elements, linear element and circular arc element, of which energy consumptions are established based on the principal theories above. Calculation method on the instantaneous cutting thickness for circular arc elements is proposed. Finally, a test example is given to validate the proposed modelling approach. With the proposed method, the separate impacts of the factors (e.g. cutting parameters, workpiece, tool) have been analysed and the physical background behind the known experimental dependence of the cutting parameters on cutting energy is revealed. [ABSTRACT FROM AUTHOR]