Ultrasonic Vibration-assisted Milling Research Articles

Effect of surface textures fabricated by two-dimensional ultrasonic vibration-assisted milling on the key surface properties of dental ceramics

The exceptionally high hardness and active plaque adhesion ability of 3Y-TZP ceramics often cause lots of oral diseases. This work intends to enhance the service performance of such ceramic dentures in human oral cavity by surface texturing technique. Efforts have been made to tackle the surface texture formation mechanism under 2D-UVAM process and establish the connection between the key surface properties and texture morphologies. The impacts of cutting parameters, vibration parameters, and tool geometry parameters on texture morphologies were rigorously studied. The coupling effect of wettability, antibacterial activity, and frictional performance of textured ceramic surfaces was also investigated. The acquired results indicate that the fish-scale texture with high density helps to enhance the hydrophobicity of the zirconia ceramics, while the wavy texture with low density promotes the ceramic material towards a hydrophilic direction. The antibacterial activity is highly related to wettability. The larger contact angle generally means the more pronounced inhibition effect on plaque adhesion. The wear of natural teeth decreases significantly after introducing textures on the ceramic surfaces, but the wear amount is not sensitive to wettability. Therefore, the hydrophobic surface can simultaneously improve the antibacterial characteristics of 3Y-TZP ceramics and its tribological compatibility with the natural teeth.

AI-Based Prediction of Ultrasonic Vibration-Assisted Milling Performance.

The current study aims to evaluate the performance of the ultrasonic vibration-assisted milling (USVAM) process when machining two different materials with high deviations in mechanical properties, specifically 7075 aluminium alloy and Ti-6Al-4V titanium alloy. Additionally, this study seeks to develop an AI-based model to predict the process performance based on experimental data for the different workpiece characteristics. In this regard, an ultrasonic vibratory setup was designed to provide vibration oscillations at 28 kHz frequency and 8 µm amplitude in the cutting feed direction for the two characterised materials of 7075 aluminium alloy (150 BHN) and Ti-6Al-4V titanium alloy (350 BHN) workpieces. A series of slotting experiments were conducted using both conventional milling (CM) and USVAM techniques. The axial cutting force and machined slot surface roughness were evaluated for each method. Subsequently, Support Vector Regression (SVR) and artificial neural network (ANN) models were built, tested and compared. AI-based models were developed to analyse the experimental results and predict the process performance for both workpieces. The experiments demonstrated a significant reduction in cutting force by up to 30% and an improvement in surface roughness by approximately four times when using USVAM compared to CM for both materials. Validated by the experimental findings, the ANN model accurately and better predicted the performance metrics with RMSE = 0.11 µm and 0.12 N for Al surface roughness and cutting force. Regarding Ti, surface roughness and cutting force were predicted with RMSE of 0.12 µm and 0.14 N, respectively. The results indicate that USVAM significantly enhances milling performance in terms of a reduced cutting force and improved surface roughness for both 7075 aluminium alloy and Ti-6Al-4V titanium alloy. The ANN model proved to be an effective tool for predicting the outcomes of the USVAM process, offering valuable insights for optimising milling operations across different materials.

Effect of forward and reverse cutting on tool wear behavior in ultrasonic vibration-assisted milling of 3D needle-punched C/SiC composites

C/SiC composites have excellent mechanical properties such as high specific strength and high temperature resistance, and are widely used in aerospace fields. However, due to its special structure and material properties, the tool wear is severe when machining with conventional methods, and the processing quality is poor. The purpose of this paper is to reveal the progressive wear behavior, wear mechanism of the tool, and its effect on machining performance in conventional milling (CM) and ultrasonic vibration-assisted milling (UVM) of C/SiC composites under forward fiber cutting (FC) and reverse fiber cutting (RC). The material removal and heat transfer models were established, and the stress distribution characteristics of cutting -edge were analyzed by finite element method (FEM). Combined with the wear morphology, cutting heat, and cutting force, the tool wear behavior and mechanism in UVM and CM under FC and RC were studied, and their effects on machining quality were analyzed. The results show that there are great differences in heat transfer and removal process between FC and RC. In UVM, the introduction of ultrasonic vibration reduces the adhesion of fine chips, weakens the strong friction and scratching between the hard chips and the cutting -edge, and alleviates the tool wear. The flank wear VB and cutting -edge wear area WA in RC are larger than those in FC, the abrasive wear is intensified, the material even peeling under mechanical shock, and the adhesive wear is more serious. When the tool wear intensifies to a certain extent, the difference of the cutting process caused by mechanical anisotropy of C/SiC composites is weakened, and the surface micro-defects and surface roughness Sa change little under FC and RC. This research contributes to the realization of high-quality and low-cost processing of C/SiC composites.

Chatter stability analysis and prediction for elliptical ultrasonic vibration-assisted milling process

Chatter stability analysis and prediction for elliptical ultrasonic vibration-assisted milling process

Theoretical Modeling and Surface Roughness Prediction of Microtextured Surfaces in Ultrasonic Vibration-Assisted Milling

Textured surfaces with certain micro/nano structures have been proven to possess some advanced functions, such as reducing friction, improving wear and increasing wettability. Accurate prediction of micro/nano surface textures is of great significance for the design, fabrication and application of functional textured surfaces. In this paper, based on the kinematic analysis of cutter teeth, the discretization of ultrasonic machining process, transformation method of coordinate systems and the cubic spline data interpolation, an integrated theoretical model was established to characterize the distribution and geometric features of micro textures on the surfaces machined by different types of ultrasonic vibration-assisted milling (UVAM). Based on the theoretical model, the effect of key process parameters (vibration directions, vibration dimensions, cutting parameters and vibration parameters) on tool trajectories and microtextured surface morphology in UVAM is investigated. Besides, the effect of phase difference on the elliptical shape in 2D/3D ultrasonic elliptical vibration-assisted milling (UEVAM) was analyzed. Compared to conventional numerical models, the method of the cubic spline data interpolation is applied to the simulation of microtextured surface morphology in UVAM, which is more suitable for characterizing the morphological features of microtextured surfaces than traditional methods due to the presence of numerous micro textures. The prediction of surface roughness indicates that the magnitude of ultrasonic amplitude in z-direction should be strictly limited in 1D rotary UVAM, 2D and 3D UEVAM due to the unfavorable effect of axial ultrasonic vibration on the surface quality. This study can provide theoretical guidance for the design and fabrication of microtextured surfaces in UVAM.

Design and surface analysis in large-amplitude longitudinal ultrasonic vibration-assisted milling of TC4 titanium alloy under dry conditions

Design and surface analysis in large-amplitude longitudinal ultrasonic vibration-assisted milling of TC4 titanium alloy under dry conditions

Effect of Duty Cycle on Cutting Force for Ultrasonic Vibration-Assisted Milling Carbon Fiber-Reinforced Polymer Laminates

Cutting force is an important factor that affects the surface quality of machining carbon fiber-reinforced polymer (CFRP). High cutting force can lead to surface damage such as the burrs and the delamination in the machining process of CFRP. Ultrasonic vibration-assisted machining (UVAM) can reduce the cutting force in the machining process. This work is focused on the relationship between the duty cycle and the cutting force in UVAM of CFRP. Based on the kinematics of UVAM, the movement of the cutting tool edge and the tool–workpiece separation in UVAM were analyzed, and a calculation formula for the duty cycle was obtained. The milling experiment of CFRP was conducted to compare the cutting force between UVAM and conventional machining (CM), and the relationship between the reduction in the cutting force in UVAM and the duty cycle was determined. The experimental results showed that when the duty cycle was 0.2916, the cutting force of UVAM was reduced by 7.4% to 27% compared with that of CM. When the duty cycle was 1, the cutting force of UVAM was reduced by −4.5% to 7.5% compared with that of CM. Therefore, the effect of reducing the cutting force of UVAM can be enhanced by adjusting the process parameters to reduce the duty cycle of UVAM, and a lower cutting force can be obtained.

Experimental Investigation on Axial Ultrasonic Vibration Assisted Milling of Cr12MoV

The conventional milling process is difficult due to the high strength and hardness of Cr12MoV, which can cause the rapid tool wear, premature failure,and poor milling quality of work platform. The ultrasonic vibration machining technology has been founded to be effective in the milling process of hard-to-cut materials like die tool steel and nickel alloys. The ultrasonic vibration assisted milling (UVM) technology is carried out the axial milling of Cr12MoV in this paper, and the average impact force Fi is influenced by the vibration amplitude A, the vibration frequency f, and equivalent mass of the vibrating part M. The mean value of cutting force Fx, Fy, and Fz decreases by 25%, 15.04%, and 17.46%, respectively. With the increase of vibration amplitudes, the value of surface roughness firstly decrease and then increase, and it is obviously lower than conventional milling. The experimental results demonstrated that the UVM technology is a feasible method for the low cutting force and high quality process of cutting Cr12MoV.

Investigating the material removal mechanism and cutting performance in ultrasonic vibration-assisted milling of carbon fibre reinforced thermoplastic

Carbon fibre reinforced thermoplastic (CFRTP) has emerged as a sustainable alternative to carbon fibre reinforced plastic (CFRP) due to its improved reparability and recyclability. CFRTP, particularly carbon fibre reinforced polyetheretherketone (CF/PEEK), is a high-performance material known for its excellent mechanical, thermal, and corrosion resistance properties, making it well-suited for extreme environments in civil aviation equipment. However, machining processes such as milling often result in defects due to the material’s high toughness and anisotropic nature. This study aims to investigate the material removal mechanism in ultrasonic-assisted milling (UAM) of CF/PEEK and compare the effects of fibre cutting angle (θ) and milling processes on milling performance. To simulate the fibre fracture mechanisms under different θ, finite element analysis (FEA) is employed. The results reveal different fracture modes, including bending, bending-shear, compression, and compression-shear, at various θ. Additionally, UAM demonstrates lower cutting forces and temperatures compared to conventional milling (CM). Notably, UAM greatly improves surface quality by reducing burr height and facilitating chip evacuation, while also enhancing surface integrity by minimizing cavity defects and fibre pull-out phenomena. These findings contribute to the development of low-damage machining methods that aim to achieve higher accuracy in CFRTP.

Analysis and modeling of cutting force considering the tool runout effect in longitudinal-torsional ultrasonic vibration-assisted 5 axis ball end milling

The longitudinal-torsional ultrasonic vibration-assisted milling (LTUVAM) can improve the machining quality compared with conventional milling (CM), and the machining quality is closely related to cutting force which is affected by the tool runout effect. In this study, a mechanistic force model for longitudinal-torsional ultrasonic vibration-assisted 5 axis ball end milling considering the tool runout effect is proposed. First, the cutting edge motion model considering the effects of tool runout and ultrasonic vibration is established. Then, based on the analysis of the cutting edge motion relative to the workpiece, the uncut chip thickness (UCT) is computed by means of the geometrical calculation method, and the engaged cutting edge elements are determined according to the Z-map method, the ultrasonic milling force model is established after determining the cutting force coefficients and tool runout parameters through calibration tests. Moreover, the impact of different parameters on dynamic separating characteristics of LTUVAM is studied by the tool-workpiece contact rate. Finally, the verification tests are carried out, and the experimental results show the effectiveness of the ultrasonic milling force model.

Stability analysis of TATWC based on UVA milling method

Difficult machining characteristics of titanium alloy materials and low rigidity characteristics of thin-walled component make Titanium Alloy Thin-Walled Component (TATWC) prone to chatter during machining, resulting in poor surface quality and other defects, which restricts the expansion and application of TATWC in the special industrial field. The appearance of Ultrasonic Vibration Assisted (UVA) milling method provides a new technology to overcome the processing problems of the TATWC. To analyze the stability of the TATWC processed by UVA milling method, first, by introducing a characterization function, a cutting force model of UVA milling method is established; The coefficients of cutting force between milling cutters and TATWC are solved through experiments. The model is verified by comparing the experimental and predicted values of cutting force; Secondly, the stability prediction model of UVA milling method based on full discrete method is established, and the effect of various process parameters on the stability of UVA milling method is researched. Finally, based on theoretical analysis, the modal characteristics of TATWC are measured through modal experiments. The feasibility of the stability prediction model of UVA milling method is verified by cutting TATWC with variable cutting depth.

Simulation and experimental study of ultrasonic vibration-assisted milling of GH4169 high-temperature alloy

GH4169 high-temperature alloy is widely used in aerospace and other fields because of its excellent fatigue, radiation, oxidation, and corrosion resistance. However, milling forces, high temperatures, and machining hardening can occur during milling processing. To explore the machining characteristics of GH4169 high-temperature alloy, an ultrasonic vibration-assisted milling model was established to study the effect of ultrasonic milling parameters on the milling process. The simulation results show that: the increase of ultrasonic amplitude can effectively reduce the machining stress, improve the chip-breaking effect and reduce the milling force; with the rise of milling speed, the separation characteristic is weakened, which is not conducive to chip breaking; the increase of radial cutting width will increase the machining stress and improve the milling force. Finally, by comparing the actual machining and simulation results, the error is within 10%, which verifies the feasibility of the simulation study and provides guidance for ultrasonic milling of GH4169 high-temperature alloy.

Ultrasonic constitutive model and its application in ultrasonic vibration-assisted milling Ti3Al intermetallics

Ultrasonic vibration-assisted technology is widely utilized in the performance research and manufacturing process of metallic materials owing to its advantages of introducing high-frequency acoustic systems. However, the acoustic plasticity constitutive model and potential mechanism, involving Ti3Al intermetallic compounds, have not yet been clarified. Therefore, the Ultrasonic-K-M hybrid acoustic constitutive model of Ti3Al was established by considering the stress superposition, acoustic thermal softening, acoustic softening and acoustic residual hardening effects according to the dislocation density evolution theory and crystal plasticity theory. Meanwhile, the mechanical behavior of ultrasonic vibration-assisted tension (UVAT) and microstructure of ultrasonic vibration-assisted milling (UVAM) for Ti3Al was investigated. Dislocation density to be overcome from initial deformation to failure of Ti3Al was calculated in UVAT and was verified in UVAM. The results indicated that the Ultrasonic-K-M model showed a good agreement with the experimental data. There was an obviously softening phenomenon after introducing the ultrasonic energy field in the Ti3Al whole deformation region, and the degree of softening was positively correlated with amplitude. Furthermore, the maximum reduction ratio in yield strength of Ti3Al was 16 % and the maximum reduction value in ultimate tensile strength was 206.91 MPa. The elongation rose first and then fell as amplitude enlarged, but only as the vibration was applied in the whole deformation region, the elongation was always greater than 14.58 %. In addition, The UVAM process significantly reduced the dislocation density increment to be overcome for Ti3Al material removal by 1.37 times, and promoted dislocation motion and cancellation to make twisted dislocations evolve into parallel dislocations. As the amplitude increased to 4 μm, the depth of the disturbed area of the plastic deformation layer increased by a maximum of 2.5 times.

An innovative study on high-performance milling of carbon fiber reinforced plastic by combining ultrasonic vibration assistance and optimized tool structures

At present, the aviation industry puts forward higher requirements for high-performance milling technology of carbon fiber reinforced plastic (CFRP). This paper proposed a sharpening milling CFRP strategy by combining of ultrasonic vibration and optimized tool structure of fluted burr tools. The sharpening cutting mechanisms of the ultrasonic vibration and tool structure were analyzed theoretically first. Next, the milling performance of optimized fluted burr tool was verified compared with conventional helical end mill and the results showed the optimized tool structure had positive effects on damage suppression and surface roughness. On this basis, Ultrasonic vibration-assisted milling (UVM) with the optimized fluted burr tool was applied to further improve the machined surface quality of T800 CFRP. The verification experimental results showed that, compared to conventional milling, both the cutting force and cutting temperature were significantly reduced in UVM, with a maximum decrement of 39.7% and 15.7% respectively. Besides, the surface defects were significantly suppressed and the surface roughness was reduced by 11.4%–37.6% in UVM. The results of this paper suggested that the combination of UVM and optimized fluted burr tool was an efficient and low damages milling strategy for CFRP.

Design of Longitudinal-Torsional Transducer and Directivity Analysis during Ultrasonic Vibration-Assisted Milling of Honeycomb Aramid Material.

This paper presents a longitudinal-torsional transducer for use during the ultrasonic vibration-assisted milling (UVAM) of honeycomb aramid material. The mechanism of longitudinal-torsional conversion was analyzed to guide the design of a vibration transducer. The transducer features five spiral grooves around the front cover plate, which function under the excitation of a group of longitudinal piezoelectric ceramics. A portion of the longitudinal vibration was successfully converted into torsional vibration. The resonant frequency, longitudinal vibration displacement and torsional amplitude at the top of the disk milling cutter were 24,609 Hz, 19 μm and 9 μm, respectively. In addition, the directivity of the longitudinal-torsional transducer was theoretically analyzed. Compared with conventional milling, UVAM with the longitudinal-torsional could significantly reduce the cutting force (40-50%) and improve the machining stability.

Enhanced dry machinability of TC4 titanium alloy by longitudinal-bending hybrid ultrasonic vibration-assisted milling

While cutting fluids are widely used in industrial mechanical machining of difficult-to-cut materials, achieving environmentally-friendly dry milling without the usage of cutting fluids by utilizing advanced manufacturing techniques makes significant sense for facilitating cleaner production. In the present work, we demonstrate the feasibility of enhancing dry machinability of TC4 titanium alloy by applying the newly proposed longitudinal-bending hybrid ultrasonic vibration-assisted milling (LBVAM), which is effective in modulating the intermittent cutting behavior between tool and workpiece material. Specifically, the kinematics and the material removal mechanisms of the LBVAM are investigated by analytical investigation, 3D finite element simulations and corresponding experiments. Simulation and experimental results demonstrate that the utilization of LBVAM enables lowering the surface roughness by 46.7% and reducing the cutting force by 43.2% from conventional milling. And the mostly prominent feature is that the surface roughness can be down to 100 nm by using the proposed LBVAM with rationally selected parameters, which is highly promising for realizing cleaner dry manufacturing of TC4 without using cutting fluids. Current work provides a feasible environmentally-friendly machining method for enhancing the dry machinability of difficult-to-cut materials.

The processing parameters optimization of UVAM-processed CuNiAl alloy based on surface integrity parameters

The surface integrity of a material has a significant impact on fretting wear performance. Based on the analysis of the material surface integrity, the machining parameters were optimized to obtain the best fretting wear performance of CuNiAl alloy. First, the effects of ultrasonic vibration-assisted milling (UVAM) processing parameters on the surface integrity of CuNiAl alloy were studied. Consequently, the relationship between UVAM processing parameters and CuNiAl alloy surface integrity parameters was established through the optimized support vector machine (PSO-SVM) model. The relationship between the surface integrity parameters, processing parameters, and fretting wear performance was established. The best fretting wear performance was obtained at a spindle speed of 147.4 m/min, feed rate of 76 mm/min, and vibration current of 199.5 mA.

Surface and subsurface analysis of TC18 titanium alloy subject to longitudinal-torsional ultrasonic vibration-assisted end milling

Longitudinal-torsional ultrasonic vibration-assisted milling is a machining method that can effectively improve the quality of the machined surface. When this method is used for the end milling of TC18 titanium alloy, however, the law of influence on the machined surface and subsurface remains unclear. In this study, we examined the effects of the ultrasonic amplitude, feed rate, and cutting speed on the machined surface morphology, roughness, surface residual stress, and subsurface microstructure in the longitudinal-torsional ultrasonic vibration-assisted end-milling process. According to the results, longitudinal-torsional ultrasonic vibration-assisted end milling can help form more obvious surface microtextures with a more distinct surface texture regularity at large amplitude, small feed rate, and high cutting speed. Compared with conventional milling, longitudinal-torsional ultrasonic vibration-assisted milling generates a larger roughness and surface residual stress and a deeper plastic deformation layer of the subsurface in the case of an obvious highly perturbed layer. In addition, the surface residual stress becomes greater and the plastic deformation layer gets deeper at a larger amplitude. When the amplitude was 5 µm, the surface residual stress was − 450.625 MPa and the depth of the deformation layer was 5.4 µm. The stress and depth increased by 21.55 % and 134.78 %, respectively, compared with those of conventional milling. The increase in the feed rate enhanced the roughness, decreased the surface residual stress, and did not significantly alter the depth of the plastic deformation layer. When the feed rate was 0.01 mm/z, the roughness was 0.383 µm and the surface residual stress was − 479.1 MPa. The feed rate and roughness increased by 42.63 % and 20.62 %, respectively, compared with those of conventional milling. With the increase in the cutting speed, the roughness increased, and the surface residual stress and the depth of the plastic deformation layer decreased. When the cutting speed was 15 m/min, the roughness was 0.31 µm, the surface residual stress value was − 454.7 MPa, and the depth of the plastic deformation layer was 5.7 µm. These three parameters increased by 17.8 %, 18.79 %, and 92.5 %, respectively, compared with those of conventional milling. This research has certain application prospect in surface machining of titanium alloy and quality control of machined surface.

Generation mechanism of surface micro-texture in axial ultrasonic vibration-assisted milling (AUVAM)

Although axial ultrasonic vibration-assisted milling (AUVAM) is promising for rapid and economical fabrication of 3D micro-texture on various surfaces, it has been a challenge to obtain micro-texture with small feature size and large height simultaneously. The mechanism and major influence factors for the formation of micro-texture by this method were explored in this study. It was found that the generation of micro-texture was mainly caused by cutting and extrusion from the flank face of the milling tool under ultrasonic vibration. Therefore, a novel 3D tool model that considered the relief angle, end cutting edge angle and the blade profile was established in simulation analysis. The good agreement between simulation and experimental results demonstrated that the influence of the flank face on the micro-texture was mainly attributed to the relief angle of the milling tool. It was the first time to report that both the height and the profile shape of the micro-texture unit were affected by the overlap and extrusion between the flank surface and the micro-texture. But this influence diminished with the increase of spindle speed. 3D sinusoid-shaped micro-texture with minimum width of 20 μm and height of 2 μm (fully reproduced the ultrasonic amplitude) was realized with the relief angle of 40° and spindle speed of 4000 rpm. Other typical textures of weave, shell, scale and corrugation were also presented to show the effective regulation of texture patterns in AUVAM. This work provides both theoretical and practical basis for such a low-cost, efficient and controllable 3D micro-texture preparation method.

Surface quality and milling force of SiCp/Al ceramic for ultrasonic vibration-assisted milling

Due to the advantages of higher specific stiffness, wear resistance, and thermal conductivity, SiCp/Al ceramics are widely used in aerospace, automation, and other industries. As a novel machining method, ultrasonic vibration-assisted milling (UVAM) can efficiently perform the milling of difficult-to-machine materials such as SiCp/Al ceramics. In this study, the contact ratio model of tool-chip is established for UVAM. Based on the presented contact ratio model, the effect of processing parameters on the contact ratio is analyzed. The microscopic model of SiCp/Al ceramic is developed by FEM simulation, which takes into account the distribution of the reinforcement particles and the internal structure of SiCp/Al ceramic. According to the simulation results, the material removal mechanism of SiCp/Al ceramic is investigated. The theoretical and experimental analysis shows that the material removal of SiCp/Al ceramic mainly consists of plastic removal of the Al matrix, the fracture of the reinforcement phase, and the debonding of the interfacial phase. Since the effect of intermittent cutting, UVAM can effectively suppress the generation of surface defects compared to conventional milling.