Ball-end Milling Tool Research Articles

Vibration monitoring of ball nose end mill tool during milling of sculptured surfaces using MUP6050 sensor

Optimization of parameters like tool path, cutter geometry, feed rate optimization, tool path and feed rate integration for sculptured surface machining has been an active research zone. The next step is to investigate the effect of vibration in ball end mill tool during milling machining of the sculptured surface. Milling machining process which is characterized by interrupted cutting, the problems of vibration occur in the machine-tool-work piece fixation device. In this work, experimental measurement of time domain signals amplitude of vibration (Acceleration) using Arduino Uno (microcontroller board) with MPU6050 (MEMS accelerometer) during machining of the surface of a selected sculpture is performed. These signals are then used to calculate the frequency of acquired signals using NI DIAdem software. The study shows the optimum values of different parameters under consideration. Such an analysis can also be helpful in fault diagnosis of CNC milling machine parts of sculptured surfaces. The investigations indication that feed is the most governing factor affecting the surface texture, and the cutting speed is the key factor affecting tool vibrations amplitudes. The results of experimental investigations are in agreement with the mathematical model generated using.

Fabrication of Micro Dimples Pattern Using Ball End Mill

In this paper, the effect of workpiece tilt angle and feed direction in producing micro dimple pattern using ball end mill tools were studied. Experiments were conducted using carbide ball end mill tools, aluminium Al 6061-T6 workpiece and using CNC machine. Three workpiece tilt angles are selected 0°30° and 45°; and two feed directions z-axis and x-axis. Visual observations using Scanning Electron Microscope (SEM) and geometry measurements using laser scanning confocal microscope were conducted on the fabricated micro dimple patterns. The results show that the workpiece tilt angle produces less burr at the edge of the dimples compared to without tilt (0°). In addition, the workpiece tilt angle can avoid the formation of undercut at the center of the dimple. The workpiece tilt angle of 30° and z-axis feed direction produced better result compared to 0° and 45° tilt angles with the value of ratio diameter/depth closer to the theoretical value.

Extraction of surface curvatures from tool path data and prediction of cutting forces in the finish milling of sculptured surfaces

To achieve higher accuracy in the prediction of cutting forces in finish milling process of sculptured parts, the curvatures of in-process workpiece surface are necessary to be taken into consideration in the calculation of cutter-workpiece engagement boundaries. These curvatures, however, are not readily available in tool path data, as the main existing source of geometrical information of the process. In this paper, first, a new straightforward algorithm is proposed to extract the principal curvatures and principal directions of the in-process workpiece surface from ball-end finish milling tool path data. These quantities, then, are employed to calculate the boundaries of engagement between the tool and workpiece geometries. In the next step, the cutting forces acting on a helical ball-end tool are formulated utilizing mechanistic approach and with the inclusion of radial run-out effect. By minimizing the square error between the predicted and experimentally measured cutting forces, the cutting force coefficients and radial run-out parameters are identified. Finally, the validity of the proposed force model is demonstrated by comparing the simulated forces with experimental measurements. The performed simulations show that the model can well capture the variation of milling forces along curved tool paths resulting from the variation of surface curvatures. Furthermore, it is shown that depending on the machining tolerance used in the tool path generation step, saw-tooth-like fluctuations may appear in the time history of milling forces originating from the approximation of curved paths by single steps (straight lines). All of the geometrical input parameters of the proposed force model are extracted from tool path data and hence it is quite flexible to be integrated into process modeling/optimization systems.

Cutting Depth Monitoring Based on Milling Force for Robot-Assisted Laminectomy

Goal: In the context of robot-assisted laminectomy surgery, an analytical force model is introduced to guarantee procedural safety. The aim of the method is to intraoperatively monitor the cutting depth via modeling the milling status. Methods: The theoretical dynamic model for the surgical milling process is based on the flute geometry of the ball-end milling tool. A particle swarm optimization algorithm is exploited to calibrate the model using the local average force, and to validate it using the denoised dynamic force. A wear detection method based on the fast Fourier transform is proposed to determine the quality of the tool geometry and to avoid using worn tools, which may lead to imprecise and unsafe operations. Results: Milling experiments were performed on machined fresh bovine femur bones. The experimental results thus obtained from the mechanical model are in good accordance with the numerical model. The proposed method can monitor the current cutting depth with an accuracy of ±0.1 mm in regions located within the depth [0.8–1.2 mm], and ±0.2 mm within [1.2–1.6 mm]. Conclusion: The proposed model can successfully estimate the milling force and the cutting depth intraoperatively in experimental conditions. Significance: This approach has the potential to improve the safety of laminectomy operations in humans, and make it more accessible to younger surgeons by lowering the required manual skills threshold. Note to Practitioners —The motivation behind this paper is driven by current safety issues existing in robot-assisted bone-cutting surgery, such as laminectomy. The main contribution of the present work is an algorithm to monitor the current cutting depth. Compared to traditional systems, the key characteristics of the introduced model are: real-time (it can be used intraoperatively); precision and safety (prediction error up to ±0.2 mm in target regions); and ease of use (no other image guidance or tracking system is required). The approach can successfully predict the current milling status and is sensitive to changes in force conditions, which is especially crucial to detect the contact point between the ball-end milling tool and the target bone. In summary, the proposed approach addresses the challenge of improving the safety of robot-assisted surgery via monitoring of the cutting depth. Experimental results on a fresh bovine femur demonstrate promising performances. The present implementation specifically targets bone milling procedures, yet it can easily be extended to a wide range of other similar clinical or industrial applications. Applicability is supported by the fact that the proposed algorithm can be implemented as a plug-in module and integrated into already existing image-guided robotic surgery platforms.

A geometric approach of working tool diameter in 3-axis ball-end milling

When machining free-form surfaces with a ball-end milling tool, the working tool diameter is constantly changing even if the tool path is constant. The reason is that the surface normal of the milled surface is continuously changing along the milling path. When the working diameter is changing, the cutting parameters also change. This variation effects the roughness homogeneity of the smoothed surface. Simultaneous five-axis milling solves this problem; however, the price and complexity of this technology can be a problem for some industrial sectors. In the paper, the geometrical background of a solution to this problem is presented for a 3-axis ball-end milling process for machining a free form surface. The paper provides the deduction of the theory by the use of homogeneous transformations. The geometrical problem of the cutting process is treated locally where the general machined surface is substituted at every point by its tangent plane. From the result of the presented method, a milling strategy can be formulated for ball-end milling that minimises the change in the momentary working diameter thus providing a more constant cutting parameter.

A study on milling of super elasto-plastic titanium alloy with a small ball end mill tool

A study on milling of super elasto-plastic titanium alloy with a small ball end mill tool

A study on milling of super elastic-plastic titanium alloy with a small ball end mill tool

A study on milling of super elastic-plastic titanium alloy with a small ball end mill tool

Temperature Field of Tool Engaged Cutting Zone for Milling of Titanium Alloy with Ball-End Milling.

When milling titanium alloy, the cutting temperature has a strong impact on the degree of tool wear and, in turn, tool life and the surface quality of the workpiece. The distribution of the temperature field on a tool’s rake face can be improved through the use of micro-textures, which help to reduce friction and, ultimately, wear on the tool. In this paper we present a new way to measure cutting temperature and examine heat distribution when milling titanium alloy with micro-textured ball-end milling tools. We first establish the heat flux density function for the contact area between the workpiece and the tool and then for the rest of the tool. Thermal stress simulation shows that adhesive wear tends to happen in the contact area and on the flank face, rather than at the tip of the tool, with the temperature distribution gradient for the rest of the tool being more uniform. The maximum value for thermal stress on the cutting edge was 2.0782 × 106 Pa. This decrease as you move away from the cutting edge along the contact area between the tool and the workpiece. Maximum deformation of the tool is also mainly concentrated at the principal contact point, with a value of 1.9445 × 10−9 m. This, too, decreases as you move away from the cutting edge and into the rest of the contact area. This research provides the basis for the optimization of tool structure and further investigation of the thermo-mechanical coupling behavior of micro-textured ball-end milling cutters when milling titanium alloy.

3D representation and CNC machining of 2D digital images

In this paper a new paradigm for CNC carving of digital images in the form of lookalike three-dimensional (3D) surfaces on wooden or metallic plaques is discussed. This work is focused on development of a single page windows based console application for conversion of a two-dimensional (2D) digital image into a 3D freeform surface representation in the form of a point cloud data and STL format. Subsequently, the 3D surface data is then used for generating an efficient toolpath data for 3-axis CNC finish machining using a ball end mill tool. The results from the developed algorithm are validated using a machining simulation in the virtual environment of an Open-GL based 3D graphical simulator ToolSim [1].

A Study on Milling of Niobium-Titanium Alloy with A Small Ball End Mill Tool

A Study on Milling of Niobium-Titanium Alloy with A Small Ball End Mill Tool

Micromilling of Ti-6Al-4V Titanium Alloy Using Ball-end Tool

The present work experimentally investigates the characteristics of micromilling of Ti-6Al-4V workpiece using ball-end tool. Micromilling were performed using 400 ¼m ball-end milling tool with the consideration of effective tool diameter. The effective tool diameter in ball-end milling is different from flat-end milling due to variation in cutting zone with axial depth of cut which accounts actual cutting speed and feed the machining. Process input variables includes cutting speed, feed per tooth and axial depth of cut, each with three levels, whereas cutting forces and surface roughness as process responses. Response surface methodology (RSM) based quadratic regression analysis was utilized to develop the correlation between process inputs and responses. Experimental results of present study on micromilling of Ti-6Al-4V using ball-end tool showed that axial depth of cut and feed per tooth could significantly influence the cutting forces and surface roughness. However, present study shows cutting speed has least effect on process responses. Finally, suitable set of process variables were proposed based multi objective optimization approach to obtain minimum cutting forces and surface roughness which were also validated with conformation test results.

High Aspect Ratio Thin Rib Shape Processing of Carbon Material for Electrical Discharge Machining Molds

Aluminum alloy die casting products are used for automotive LED lamp installation parts. The high aspect ratio shape used for large-volume heat problems needs thin rib parts. In the present study, we obtained basic data for the development of long axis type end mill tools for electrical discharge machining carbon material processing. At the same time, to evaluate the prototype development work, a special tool that enables high aspect ratio thin rib geometry processing was used. Longitudinal direction traverse cutting was done with a small diameter ball end mill tool in the carbon material for electrical discharge machining mold. The transfer accuracy and pick feed shape in the finished surface, the cutting resistance force, and the cutting edge shapes were examined to clarify the relationship between the cutting conditions set. Prototype development of the small-diameter end mill tool with a high rigidity, long axis was done using FEM numerical analysis method. The results showed that the small-diameter ball end mill tool with a tapered length axis in the prototype development had transfer accuracy of the cutting edge shape, and it was possible to reduce the finished surface roughness. Factors such as differences in tool shape are considered to greatly affect the tool rigidity.

小径ボールエンドミルによる超弾塑性型チタニウム合金のミーリング加工に関する研究

小径ボールエンドミルによる超弾塑性型チタニウム合金のミーリング加工に関する研究

Time-averaged and Instantaneous Mechanistic Models using Artificial Force Synthesis in Helical End Milling

This paper aims to develop field-deployable mechanistic milling models with the aid of the Virtual Machining Simulation Environment (VMSE). Stabler's rule and sharp tool hypotheses were adopted. VMSE force components for artificial materials with unit normal (Kn) and friction (Kf) force coefficients were least-squares-fit to experimental values to obtain actual Kn and Kf and then functionally fit to chip thickness h, speed v and normal rake angle α. The new approach was tested with a simple ball end mill tool. Both time-averaged (MMa model) and location-averaged instantaneous (MMi model) force components from a subset of experimental data were used. Physical force components reported by the VMSE with both MMa and MMi for the complete test matrix agreed with their experimental counterparts. MMi significantly expanded the range of h and was identical to MMa in the common range.

The Study of Coated Carbide Ball End Milling Tools on Inconel 718 Using Numerical Simulation Analysis to Attain Cutting Force and Temperature Predictive Models at the Cutting Zone

The unique properties of Inconel 718 make it a challenging material to machine especially in ball end milling operations due to high cutting force and temperature concentrated at the cutting zone. These essentially lead to accelerated tool wear and failure resulting in high costs and loss of production. In this research, finite element numerical simulation was performed using AdvantEdge to simulate ball end milling using an 8mm TiAlN coated carbide tool. Response Surface Methodology (RSM) is applied by using a 3 level 3 factorial Box-Behnken design of experiment with different combinations of cutting speed, feed rate, and depth of cut parameters with a selected range of parameters to simulate finishing operations. Temperature contour from finite element analysis showed that the highest temperature occurs near the depth of cut line just before the chip separates from the workpiece. Using multiple linear regression, a quadratic polynomial model is developed for maximum cutting force and a linear polynomial model peak tool temperature response respectively. Analysis of Variance (ANOVA) showed that feed rate had the most significance for cutting force followed by depth of cut. Also, cutting speed was found to have little influence. For peak tool temperature, cutting speed was the most significant cutting parameter followed by feed rate and depth of cut.

Reprint of “A study of CVD diamond deposition on cemented carbide ball-end milling tools with high cobalt content using amorphous ceramic interlayers”

In this paper, CVD diamond coatings are deposited on cemented carbides with 10wt.% Co using amorphous SiO2 and amorphous SiC interlayers. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Raman spectrum and X-ray diffraction (XRD) are carried out to characterize the microstructure and composition of as-deposited films. Moreover, the adhesion and cutting performance of as-fabricated diamond coatings are studied. Indentation tests show that the amorphous ceramic interlayers can enhance the adhesion between diamond films and WC–Co substrates. The cutting tests against zirconia indicate that the tools with amorphous ceramic interlayered diamond coatings exhibit improved cutting performance. The amorphous ceramic interlayers can improve the adhesive strength and wear endurance of diamond coatings on WC–10wt.% Co substrates, which provide a viable way for adherent diamond coatings on cemented carbide tools with high cobalt content.

小径ボールエンドミルを用いた超弾塑性型チタニウム合金の微細加工に関する研究

β-type titanium alloy exhibiting super-elasticity and super-plasticity was developed. This alloy has high tensile stress and low young's modulus too. The excellent characteristics of this alloy indicate its likely application in the field of dental implant. However, the characteristics of this alloy is lost by severe heat environment and external force. In this study, the effect of cutting temperature and cutting force on the affected layer was investigated by milling with small ball end mill tool in order to decrease the affected layer by cutting process. The thickness of affected layer indicated a tendency to increase with the cutting speed. And at the cutting speed of 16.0m/s, the thickness of the affected layer exceeded 2.5μm because of increasing of cutting temperature. On the other hand, the thickness of affected layer was 0.7μm at the condition of the environment of high cutting force. Thus, the affected layer influenced by cutting temperature.

Intelligent Prediction of Tool Wear in Ball-End Milling Process Based on Dimensionless Cutting Force Ratio

This research proposed an in-process tool wear prediction during the ball-end milling process by utilizing the cutting force ratio. The dimensionless cutting force ratio is proposed to cut off the effects of the work material and the combination of cutting conditions. The in-process tool wear prediction model is developed by employing the exponential function, which consists of the spindle speed, the feed rate, the depth of cut, the tool diameter, and the cutting force ratio. The experimentally obtained results showed that the cutting force ratio can be utilized to predict the tool wear of ball-end milling tool. The new cutting tests have been employed to verify the model and the results run satisfaction. It has been proved that the in-process tool wear prediction model can be used to predict the tool wear regardless of the cutting conditions with the highly acceptable prediction accuracy.

A study of CVD diamond deposition on cemented carbide ball-end milling tools with high cobalt content using amorphous ceramic interlayers

In this paper, CVD diamond coatings are deposited on cemented carbides with 10wt.% Co using amorphous SiO2 and amorphous SiC interlayers. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Raman spectrum and X-ray diffraction (XRD) are carried out to characterize the microstructure and composition of as-deposited films. Moreover, the adhesion and cutting performance of as-fabricated diamond coatings are studied. Indentation tests show that the amorphous ceramic interlayers can enhance the adhesion between diamond films and WC–Co substrates. The cutting tests against zirconia indicate that the tools with amorphous ceramic interlayered diamond coatings exhibit improved cutting performance. The amorphous ceramic interlayers can improve the adhesive strength and wear endurance of diamond coatings on WC–10wt.% Co substrates, which provide a viable way for adherent diamond coatings on cemented carbide tools with high cobalt content.

A comparison of solid model and three-orthogonal dexelfield methods for cutter-workpiece engagement calculations in three- and five-axis virtual milling

Virtual simulation of three- and five-axis milling processes has started to become more important in recent years in various industries such as aerospace, die-mold, and biomedical industries in order to improve productivity. In order to obtain desired surface quality and productivity, process parameters such as feedrate, spindle speed, and axial and radial depths of cut have to be selected appropriately by using an accurate process model of milling. Accurate process modeling requires instantaneous calculation of cutter-workpiece engagement (CWE) geometry. Cutter-workpiece engagement basically maps the cutting flute entry/exit locations as a function of height, and it is one of the most important requirements for prediction of cutting forces. The CWE calculation is a challenging and hard problem when the geometry of the workpiece is changing arbitrarily in the case of five-axis milling. In this study, two different methods of obtaining CWE maps for three- and five-axis flat and ball-end milling are developed. The first method is a discrete model which uses three-orthogonal dexelfield, and the second method is a solid modeler-based model using Parasolid boundary representation kernel. Both CWE calculation methods are compared in terms of speed, accuracy, and performance for three- and five-axis milling of ball-end and flat-end mill tools. It is shown that the solid modeling-based method is faster and more accurate. The proposed methods are experimentally and computationally verified in simulating milling of complex three-axis and five-axis examples as well as predicting cutting forces.