Tool Tip Research Articles

Investigation of Temperature at Al/Glass Fiber-Reinforced Polymer Interfaces When Drilling Composites of Different Stacking Arrangements

This attempt covers an investigation of cutting temperature at interfaces of Fiber Metal Laminates (FMLs) made of glass fiber-reinforced polymer (GFRP) stacked with an Al2020 alloy. GFRP/Al/GFRP and Al/GFRP/Al composite stacks are both investigated to highlight the effect of stacking arrangement on thermal behavior within the interfaces. In a first test series, temperature history is recorded within the metal/composite stack interfaces using preinstalled thermocouples. In a second test series, a wireless telemetry system connected to K-type thermocouples implanted adjacent to the cutting edge of the solid carbide drill is used to record temperature evolution at the tool tip. Focus is put on the effects of cutting speed and stacking arrangement on the thrust force, drilling temperature, and delamination. From findings, the temperature histories show high sensitivity to the cutting speed. When cutting Al/GFRP/Al, the peak temperature is found to be much higher than that recorded in GFRP/Al/GFRP and exceeds the glass transition point of the GFRP matrix under critical cutting speeds. However, thrust force obtained at constitutive phases exhibits close magnitude when the stacking arrangement varies, regardless of cutting speed. Damage analysis is also discussed through the delamination factor at different stages of FML thickness.

Unsupervised detection and mapping of sparks in the Electrochemical Discharge Machining (ECDM) process

Material removal in electrochemical discharge machining is caused by sparks generated in a tool immersed in an electrolytic solution. Being the primary machining agent in this non-contact machining process, mapping the locations of microscopic sparks is of great interest. The distribution of sparks around the tool surface could give insights into the machined hole properties like the size, surface finish, and depth as compared to the machining parameters such as applied voltage, tool size, rotation speed, and feed rate. This paper is focused on detecting sparks in photographs of the ECDM process captured using a high-speed camera. A novel approach of using a tri-planar reflective surface for capturing the location of sparks in 3D space using a 2D camera output is attempted. Traditional spark detection methods use neural network classifiers that need labeled data for training. This labeled data often comes from human intervention and contains inherent biases that could lead to misclassification. In this paper, an unsupervised spark detection methodology is demonstrated, which eliminates the need for human intervention and relies on the number of neighboring pixels detected in regions of interest (ROIs). The feasibility of using adaptive background modeling to classify thousands of images and identify the ones with sparks is demonstrated in this work. The masking technique combining effects of erosion followed by dilation is used to determine the exact boundaries of the spark contours in every image. Centroids for each of these contours are then transformed from the skewed coordinate system as observed in camera images, to a three-dimensional orthogonal coordinates system centered around the tool. The same procedure is repeated for various voltages to benchmark the distribution of sparks around a tool tip in an ECDM process.

Co-Kriging model-based multi-fidelity regression for refining milling stability predictions of variable tool overhang length using limited experimental data

Determining chatter-free machining parameters is critical in process planning since chatter vibrations significantly affect machining quality and production efficiency. Stability lobe diagram is essential in selecting chatter-free machining parameters, but its predictions confront challenges in both theoretical accuracy and experimental efficiency. To address this, the Co-Kriging modelling is introduced to predict the tool overhang length-dependent stability limits with limited experiments. First, tool tip dynamics and cutting force coefficients of a source overhang length are roughly identified to obtain sufficient low-fidelity (LF) theoretical stability limits. The entropy-based sampling and affine transformation are used to sequentially obtain high-fidelity (HF) experimental stability limits and update LF stability limits. HF and updated LF datasets are combined to train a multi-fidelity (MF) Co-Kriging model. For a target overhang length, MF stability limits of the source overhang length serve as LF data, and a minimum mean absolute percentage error (MAPE)-based sampling guides the acquisition of HF stability limits. Combining HF data and LF data processed by affine transformation to train a target Co-Kriging model. Case studies reveal that the proposed method exhibits lower MAPE values and significantly outperforms other comparison methods in predicting experimental stability limits, particularly when confronted with limited experimental data.

Influence of TiAlN coating thickness in dry machining of AISI 1045 steel using Finite Element simulation and experiments

High performance cutting can be accomplished using coated tools with optimal coating thickness. Therefore, Finite Element (FE) simulation and experimental investigation are employed to study the influence of thickness of TiAlN coating in the range of 1 to 4 μm during face milling of AISI 1045 steel under dry condition. FE simulation is successful in effectively investigating the influence of coating thickness in machining performance in terms of cutting forces, Von Mises stress, tool tip temperature and crater wear of uncoated as well as coated milling inserts. Simulation results have predicted cutting forces and temperature with maximum errors of 9.21 % and 12.20 %, respectively. FE simulation further demonstrates 2.100 and 1.602 μm as the depths of crater for 1 and 3 μm thick TiAlN coated inserts, respectively, which are also validated by the experiments. The experimental results demonstrate that 3 μm thick coated tool is superior in mitigating cutting forces, particularly under higher cutting speed (150 m/min), bringing down tool tip temperature (6.67 %) and machined surface roughness (18.18 %) as compared to 1 μm thick TiAlN coated milling insert. The results obtained from the current research work clearly indicate that the effect of coating thickness can be effectively investigated using the FE simulation before finalising the optimal coating thickness for the coating depositions and machining experiments.

Vibration energy-based indicators for multi-target condition monitoring in milling operations

The demand for intelligent process monitoring is increasing in aerospace manufacturing to ensure tight tolerances and high surface quality. Real-time monitoring in machining is crucial for machined accuracy and process reliability, reducing production times and costs, and enhancing automation of the manufacturing process. This study presents a robust multi-target condition monitoring method based on the vibration signals. Firstly, three new energy ratio indicators with dimensionless characteristics were defined for tool wear, breakage, and chatter monitoring. Secondly, the vibration energy loss from the tool tip to the tool holder, and spindle housing was measured and compared, and the rules of vibration loss from the tool tip to the spindle housing were revealed. Using force signals as a reference, the monitoring performance of industrially acceptable acceleration and sound signals in multi-target condition monitoring was quantitatively analyzed. Finally, the performance of the proposed vibration energy-based indicators was experimentally illustrated and quantitatively evaluated. It is shown that these indicators can be used to discriminate between tool breakage and chatter, as well as to assess tool wear. The new monitoring method can also minimize the costs of process monitoring by reducing the use of expensive sensors or overusing multiple sensors in a smart manufacturing system.

Investigation on two-dimensional ultrasonic vibration plane turning method based on elliptical plane swinging strategy along short axis

In the ultrasonic elliptical vibration cutting (UEVC) process, the surface morphology suffers from the large fluctuation of ridge height and residual height, which has restricted the development of UEVC technology. Therefore, on the basis of the elliptical plane swinging strategy along a short axis, a surface topography improvement method (i.e., swing ultrasonic elliptical vibration turning (SUEVT)) for two-dimensional ultrasonic vibration plane turning is proposed in this study. The core idea of the method is to swing the ultrasonic elliptical vibration plane along the short axis to form a machining inclination angle, which reduces the ridge height of the machined morphology to a certain extent, thereby optimizing the surface microstructure and reducing the surface roughness. First, this study establishes a mathematical model of the tool tip trajectory of ultrasonic elliptical vibration under different swing angles, theoretically analyzes the influence of swing angles on the tool tip trajectory and surface topography, and provides a theoretical basis for revealing the surface topography formation mechanism of SUEVT. Second, an engineering practice scheme of SUEVT is proposed, and a processing experiment platform is built. Finally, cutting experiments of SUEVT for TC4 titanium alloy were conducted, studying the influence of swing angles on surface topography and roughness and assessing the feasibility of the method. Results showed that compared with ultrasonic elliptical vibration turning (UEVT), SUEVT has certain advantages in improving surface morphology. When the swing angle of SUEVT is 15°, the surface roughness decreases the most, reaching 19.00 %. Under the condition of SUEVT θ = 15°, the surface roughness decreases first and then increases with the increase in spindle speed, while it is proportional to the feed speed and ultrasonic power. The method proposed in this study can provide new methods and new ideas for ultrasonic elliptical vibration high surface quality machining.

Impact of Toolpath Pitch Distance on Cutting Tool Nose Radius Deviation and Surface Quality of AISI D3 Steel Using Precision Measurement Techniques.

The selection of the right tool path trajectory and the corresponding machining parameters for end milling is a challenge in mold and die industries. Subsequently, the selection of appropriate tool path parameters can reduce overall machining time, improve the surface finish of the workpiece, extend tool life, reduce overall cost, and improve productivity. This work aims to establish the performance of end milling process parameters and the impact of trochoidal toolpath parameters on the surface finish of AISI D3 steel. It especially focuses on the effect of the tool tip nose radius deviation on the surface quality using precision measurement techniques. The experimental design was carried out in a systematic manner using a face-centered central composite design (FCCD) within the framework of response surface methodology (RSM). Twenty different experiment trials were conducted by changing the independent variables, such as cutting speed, feed rate, and trochoidal pitch distance. The main effects and the interactions of these parameters were determined using analysis of variance (ANOVA). The optimal conditions were identified using a multiple objective optimization method based on desirability function analysis (DFA). The developed empirical models showed statistical significance with the best process parameters, which include a feed rate of 0.05 m/tooth, a trochoidal pitch distance of 1.8 mm, and a cutting speed of 78 m/min. Further, as the trochoidal pitch distance increased, variations in the tool tip cutting edge were observed on the machined surface due to peeling off of the coating layer. The flaws on the tool tip, which alter the edge micro-geometry after machining, resulted in up to 33.83% variation in the initial nose radius. Deviations of 4.25% and 5.31% were noted between actual and predicted values of surface roughness and the nose radius, respectively.

Performance assessment of the multi-nozzle injection MQL system for cleaner machining of hardened AISI D2 steel concerning power consumption

ABSTRACT Sustainable hard machining is a pressing need in manufacturing industries for techno-social, economic and environmental benefits to machine difficult-to-cut materials. Thus the present study investigates finish turning of hardened AISI D2 steel using a MTCVD coated carbide insert (TiN-TiCN-Al2O3) with geometry CNMG120408FW and grade WK05CT under a multi-nozzle MQL system using LRT 30 mineral oil (50 ml/hr flow rate, 6 bar compressed air pressure, 30 mm nozzle distance from tool tip) for minimal quantity lubrication at both the rake and flank zones for assessment of machinability. Flank wear lies between 0.79 and 0.155 mm and within the failure criterion limit of 0.2 mm. Arithmetic surface roughness trials have been within 0.361–0.877 microns and within the 1.6 microns acceptable range. The cutting temperature has been between 80.7°C and 226.9°C and even below 200°C in the majority of runs. The cutting power lies within 0.432kW–0.804kW. The optimal parametric combination has been found to be d=0.1 mm, f=0.05 mm/rev and v=80 m/min respectively and improvement has been observed over dry cutting. RSM models are found to be statistically significant. Application of multi-nozzle MQL in machining of hardened steel outperformed through machinability assessment and may be adopted in shopfloor for sustainability..

Comprehensive characterization of spark plasma sintered ZrB2-SiCp-SiCw composite and its corresponding orthogonal cutting simulation

A composite consisting of 12.5 wt% SiC particles and 12.5 wt% SiC whiskers in a ZrB2 matrix (ZrB2-SiCp-SiCw) was produced using spark plasma sintering. The sintering process was carried out at a temperature of 1900 °C and a pressure of 40 MPa for a duration of 7 minutes. X-ray photoelectron spectroscopy analysis confirmed the presence of C-C, C-Si, O-B, O-Zr, O-Si, and Zr-B bonds. Scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses revealed the presence of silicon and carbon in the ZrB2 phase. The nano-indentation hardnesses and elastic moduli of ZrB2 and SiC were measured as 2104.58 and 2268.97 Vickers and 397.58 and 394.27 GPa, respectively, under a load of 100 mN and a loading rate of 0.4 mN/sec. The orthogonal cutting process of an Al6061 workpiece with a ZrB2-SiCp-SiCw cutting tool was simulated using DEFORM 2D software. The response surface method was used to develop a model to evaluate the relationship between cutting parameters (tool tip radius, cutting speed, and rake angle), cutting force, feeding force, and maximum temperature. It was found that cutting and feeding forces decrease with increasing cutting speed and rake angle, while increasing the tool tip radius increases these forces. The tool and workpiece endure a higher maximum temperature as the cutting speed and tool tip radius rise, but the maximum temperature drops as the rake angle increases.

Cutting force prediction model considering tool-chip contact interface friction behavior in ULTVAM of Ti-6Al-4V

Ti-6Al-4V is widely used in the aviation industry because of its high strength, and good heat resistance. However, severe tool wear on the rake face occurs during the milling of Ti-6Al-4V, which is caused by intense friction between the tool rake face and the chips. To investigate tool wear in the milling of Ti-6Al-4V, ultrasonic vibration is introduced, and a cutting force prediction model that considers tool-chip contact interface friction behavior in Ultrasonic Longitudinal-Torsional Vibration-Assisted Milling (ULTVAM) is proposed in this paper. First, the tool tip motion trajectory and dynamic cutting thickness under ULTVAM were analyzed calculated, and compared with those in Common Milling (CM). Subsequently, the effects of ultrasonic vibration on the shear force under the ultrasonic softening effect, the friction force, and the friction reversal force on the tool-chip contact interface were investigated. A dynamic milling force model under ULTVAM was established before and after friction force reversal caused by ultrasonic longitudinal-torsional vibration. Finally, numerous experiments were conducted to validate the proposed model, and the experimental results indicated that the calculated dynamic milling forces agreed well with the measured values, with errors in the X and Y directions of 5.51% and 10.23%, respectively. In addition, the average roughness of the workpiece surface also decreased (1.08, 0.9, 0.6, 0.7 μm under ultrasonic amplitudes of 0, 1, 2, and 3 μm) and the tool wear state improved on the rake face under ULTVAM.

Tool Wear in GGG50 Cast Iron Milling Environments

In the present study, the impression of manufacturing parameters on cutting tool tip wear in the milling operation of GGG50 cast iron material with carbide coated cutting tool inserts was investigated. Taguchi orthogonal L18 experimental sequence was applied as the experimental design. As processing parameters; cutting speed, coolant and feed rate were chosen. In the test results, the amount of wear on the cutting tool tips was examined. Optimum processing multiparameters were determined by the Taguchi. Analysis of variance (ANOVA) was used to analyses the effect of input parameters on the cutting tool tip. Consequently, it has been determined that the wear is high in the working environment where the coolant is open and the cutting speed is high. In order to keep the cutting tool tip wear at a minimum level, the most suitable machining parameters are; coolant = closed, cutting speed = 160 mm/min, feed rate = 0.3 mm/rev. It was determined that the tip feed rate had little impression on tool wear.

Tool-edge geometry effects in semi-to-finish cut machining operations on subsurface integrity and tool thermo-mechanical loadings: A coupled damage-fracture energy based finite element approach

Present work put forwards a numerical approach to quantify the effects of honed-edge and chamfered-edge tools on residual stresses and end-burr generation while performing semi-to-finish cut machining operations. Maximum stresses and temperatures experienced by tools are computed to predict tool wear intensity at its various sections. Furthermore, the impact of tool edge geometry on fracture and the size of the material damage zone ahead of the tool tip has also been detailed. Chip formation, its evolution and separation have been realized using a coupled damage-fracture energy model considering coupled temperature-displacement simulations in two steps modeling strategy: cutting step and stress relaxation and cooling step. A numerical model has been validated with previous experimental results of chip morphology and cutting forces when machining was performed under similar cutting conditions and tool geometrical profile.

An effective investigation of chatter prediction system on Al6061 alloy in an end milling process

Visual examination of the surface topography, in conjunction with the other sensors, may confirm the existence of chatter. Online chatter detection during real machining operations is possible with the use of sensors, and the presence of noise in their output and restricted bandwidth are the major drawbacks of these sensors. Productivity drops and manufacturing costs go up when there is a lot of chatter in the machining process. In the present paper, an integrated spindle tool system is modeled using finite element method with Timoshenko beam theory including rotational and shear deformation effects. To maximize the average stable depth of cut in an end milling process while simultaneously minimizing the chatter vibration levels, real time and offline strategies have been investigated. Machining experiments performed on Al6061-alloy specimens provide an empirical confirmation of the stability boundaries. The surface topography methods such as scanning electron microscope (SEM) and optical microscope images along with vibration levels are considered, to identify chatter marks under various machining conditions, which helps to assure cutting process stability. Stability lobe diagrams are plotted with these derived conditions and observed at an incremental level in the axial depths of the cut. The methodology shown in this paper improves the machining stability of the end milling with the reduction in the tool tip vibrations.

Coupled fluid-structure-interaction simulation approach for correction of the thermal tool elongation to improve the milling precision

During milling operation, the position of the tool centre point (TCP) is affected by structural displacements, which are caused by force loads and heat input inside the machine as well as machining induced thermal loads. These thermal loads result in considerable thermal deformations of tool holder, tool, and accordingly the TCP position. They can be summed up to about tens of microns and compromise the dimensional accuracy. The objective was to develop an integrated, numerical simulation-based approach for future TCP correction for a milling process using characteristic diagrams. For this, a complex Fluid-Structure-Interaction (FSI) simulation model predicts the uni-axial displacement in the longitudinal direction of the TCP due to a specified process heat source at the tool tip. As a partial result, the simulation has reached its performance limits, under the restriction of a reasonable simulation time in order to produce characteristic diagrams for application on a milling machine. The calculated thermally induced displacement can be further processed with the aid of Design of Experiments (DoE) and response surface methodology (RSM), depending on the thermal process load and coolant volume flow rate. That results in characteristic diagrams for the displacement as a function of process parameters. In this study the calculated value for thermally induced TCP displacement covers a span from 10 μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu$$\\end{document}m to 80 μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu$$\\end{document}m, with a strongly nonlinear behaviour. Subsequently, this forms the basis for a future implementation of characteristic diagrams in the machine control system for online correction of thermal tool errors.

Optimization of tool wear and surface roughness in ST-37 steel turning process with varying tool angles and machining parameters

The process of cutting low carbon steel (ST-37) typically utilizes High-Speed Steel (HSS) tools owing to their high hardness, affordability, and ease of shaping tool geometry. In machining, tool geometry plays a crucial role in the material cutting process and determines the quality of the final product, particularly surface roughness. The objective of this research is to achieve optimal surface roughness by varying the tool geometry and nose radius. This study employed an experimental approach using ST-37 and HSS tools. The variations in tool geometry include side rake angles of 12°, 15°, and 18°; side cutting edge angles of 85°, 80°, and 75°; and nose radii of 0 mm, 0.4 mm, and 0.8 mm. The machining parameters applied consist of a cutting depth of 1 mm and 2 mm, spindle rotation speeds of 185 rpm, 425 rpm, and 624 rpm, and a feed rate of 0.05 mm/rev, 0.075 mm/rev, and 0.1 mm/rev. Tool wear measurements were captured using a USB camera, whereas the surface roughness was assessed using a surface roughness tester. The impact of the tool geometry on the surface roughness was analyzed using the Taguchi-Grey Relational Analysis (Taguchi-GRA) and ANOVA methods. The optimal combination for ST-37 lathe machining with a sharpening tool is: A1 (cutting depth 1 mm), B1 (cutting speed 17.42 m/min), C3 (feed 0.05 mm/rev), D1 (corner radius 0 mm), E3 (side rake angle γ 18°), and F3 (side cutting edge angle γ 75°). According to the Analysis of Variance (ANOVA), three factors—cutting speed, tool tip angle, and chip angle—should be considered to achieve minimal tool wear and desirable surface roughness during machining

Effects of longitudinal ultrasonic vibration on tool wear behaviors in side milling of GH4169D superalloy

The GH4169D superalloy, a novel Nickel-based material widely acknowledged for its exceptional high temperature strength and fatigue resistance properties, plays a pivotal role in the production of critical components of contemporary aero-engines. The material, however, falls under the category of a typical difficult-to-cut metallic material due to the substantial cutting forces and significant tool wear experienced during the machining process. In this paper, a method of longitudinal ultrasonic vibration assisted side milling (LUVM) was developed to extend tool life. The investigation primarily involved an analysis of tool wear behaviors, including milling force, tool life, morphologies of tool wear, and various underlying wear mechanisms in LUVM and conventional milling (CM) of GH4169D superalloy. The results demonstrate that LUVM exhibits the advantage of reducing milling forces and prolonging tool life in comparison to CM. Throughout the entire milling process, the maximum milling force of LUVM is consistently smaller than that of CM, displaying a comparatively slower growth trend. At the conclusion of machining, while CM reaches a maximum milling force of 360.3 N, the maximum milling force of LUVM (195.9 N) is significantly lower. The tool life of LUVM is 28.2 min, representing a 33 % increase compared to CM (21.2 min). Material adhesion, coating delamination, and built-up edge (BUE) phenomena can be observed on both the tool rake face and flank face in CM. LUVM contributes to mitigation of bonding phenomena, prevention of BUE formation, and avoidance of abrasive wear in comparison to CM. However, it is prone to lead to tool tip chipping. For CM, the tool wear mechanisms include adhesive wear, oxidation wear, abrasive wear and diffusion wear; whereas for LUVM, the tool wear mechanisms comprise of adhesive wear, oxidation wear and diffusion wear.

Investigation on fiber fracture mechanism and milling force model of CF/PEEK by ultrasonic milling

Ultrasonic milling can achieve high machining efficiency and surface quality on CF/PEEK composites due to its advantages of low cutting force, high material removal rate, improved surface quality, long tool life, and eco-friendly machining technology. This method is widely used in many scenarios such as aerospace, navigation, and new types of weapons. However, the changes in fiber fracture mode and the effects of fiber friction caused by high-frequency ultrasonic vibration cannot be ignored. To study this, first, a fiber fracture model is constructed based on experiments to describe the fiber fracture mechanism. Then, the machined surface and subsurface are analyzed to establish the relationship between feed speed and fiber deformation depth. Increasing the feed can increase the fiber deformation depth by 3.17 times. Finally, an analysis of the single fiber fracture mechanics is carried out and a force model is created that considers the friction between the tool tip and the fiber during ultrasonic milling. The predictive force model, integrated with the fiber distribution, was validated against experimental results, showing a maximum force error of 5.722 %. This model effectively explains the fracture mechanism of CF/PEEK fibers during ultrasonic milling at the microscopic level.

Stability of Micro-Milling Tool Considering Tool Breakage

Micro-milling, widely employed across various fields, faces significant challenges due to the small diameter and limited stiffness of its tools, making the process highly susceptible to cutting chatter and premature tool breakage. Ensuring stable and safe cutting processes necessitates the prediction of chatter by considering the tool breakage. Crucially, the modal parameters of the spindle–holder–tool system are important prerequisites for such stability prediction. In this paper, the FRFs of the micro-milling tool are calculated by direct frequency response functions (FRFs) of the micro-milling cutter and cross-FRFs between a point on the shank and one on the tool tip. Additionally, by utilizing a cutting force model specific to micro-milling, the bending stress experienced by the tool is computed, and the tool breakage curve is subsequently determined based on the material’s permissible maximum allowable stress. The FRFs of the micro-milling tool, alongside the tool breakage curve, are then integrated to generate the final stability lobe diagrams (SLDs). The effectiveness and reliability of the proposed methodology are confirmed through a comprehensive series of numerical and experimental validations.

Identification of dynamic coefficient matrix for drilling process simulations from measured tool geometry, axial force and torque

This paper aims to quantitatively analyze the relationship between forces acting on the tool tip and tool movement during drilling operations. The study encompasses axial and lateral vibrations superimposed on the nominal tool movement, arising from rigid body motion (rotational and axial velocities). Specifically, only forces attributed to the cutting process are considered, excluding considerations of indentation forces around the chisel edge. The research adopts a generalized approach, spanning from tool measurements to establishing the force model. The investigation involves measuring cutting forces and correlating them with the varying rake and inclination angles of the drill’s cutting edges. An analytical model is proposed to describe the distribution of all local force components along drill edges, considering the evolution of forces and geometry. The dynamic coefficient matrix is evaluated by using the identified cutting coefficient and tool geometry. Validation of the proposed methodology is demonstrated through drilling experiments on Ti6Al4V alloy, utilizing three solid carbide drills with distinct geometries. The proposed procedure allows complete identification of the dynamic characteristics from the measurements taken at the entrance stage of hole drilling operation. Moreover, the influence of tool geometry on cutting coefficients and dynamic coefficient matrices are discussed.

Cutting Performance of a Longitudinal and Torsional Ultrasonic Vibration Tool in Milling of Inconel 718

Inconel 718 has excellent thermal and chemical properties and is widely used in the manufacture of aerospace parts; however, there are some problems in the machining of Inconel 718, such as a large milling force, serious tool wear, and poor surface quality. In this research, a type of longitudinal–torsional ultrasonic milling (LTUM) tool is designed based on theoretical computations and FEM simulation analysis. To verify the design rationality of the developed LTUM tool, milling experiments are performed. It is verified that the LTUM tool can realize an elliptical vibration path at the tool tip. The resonance frequency of the tool is 21.32 kHz, the longitudinal amplitude is 6.8 µm, and the torsional amplitude is 1.4 µm. In the milling of Inconel 718, the experimental data of LTUM are compared with those of conventional milling (CM). The comparative experiments show that the LTUM tool can effectively lessen the milling force and tool wear in the milling of Inconel 718, improve the surface quality, inhibit the generation of burrs, and improve the chip breaking ability. The application potential of the LTUM tool in high-performance milling of Inconel 718 parts is proven.