Tool Inclination Research Articles

Influence of Cutter Orientations on Cutting Force in Ball End Milling of TC17

In order to improve the ball end milling multi-axis milling titanium alloy workpiece machining method, the influence of cutter orientations on cutting force is studied in this paper by experiment. This paper uses the tool rotation angle and the tool inclination angle to describe the cutter orientations. Analyse the cutting force under different milling posture. The results prove that, when the tool inclination angle is constant, the change of tool rotation angle will cause changes in the value and direction of the cutting force. Though maintain the tool rotation angle, the change of the tool inclination angle will change the cutting speed, thus make the cutting force decrease first then increase.

Influence of tool inclination on chip formation process and roughness response in ball-end milling of freeform surfaces on Ti-6Al-4V alloy

ABSTRACTAn experimental test part, which was made up of flat, concave, and convex surfaces of variable curvatures, was designed to be fabricated in a four-axis machining center. Aluminum alloy 7075 and titanium alloy Ti-6Al-4V were used for the fabrication. Within the finishing process, smeared/adhered material was found in some areas of the concave and convex surfaces of the titanium alloy. On the other hand, smeared/adhered material was not found in the aluminum alloy. To characterize the type of defects, the 3D roughness parameters of the surfaces were measured by confocal microscopy, and surface morphology was observed using optical microscopy and scanning electron microscopy. The kinematics of the ball-end milling process was modeled and it was found that the lead and tilt angles between the tool axis and surface normal vector vary continuously, producing transitions between oblique-plunge-push-up milling and oblique-reverse-push-up milling. This causes variation in the thickness behavior during the chip formation process. It was found that the lead angle has a moderate influence, while the tilt angle has a strong effect on the quality of the surfaces of the titanium alloy, with negative tilt angles producing the worst surfaces when there was the oblique-plunge-push-up milling process.

Machinability study of single-crystal sapphire in a ball-end milling process

Sapphire has received increasing attention as an engineering material even though its machinability is still an issue. In this study, the influence of the milling process parameters on the surface quality of single-crystal sapphire is investigated. Due to the hardness and brittleness of the sapphire substrate, crack initiation becomes the main concern with respect to up- and down-milling, feed rate, tool inclination angle and tool wear. With an inclined ball-end mill cutter in feed direction various cutting tests were performed to find optimal parameters for machining microchannel. It was observed that the feed rate and depth of cut are dominant factors for the surface quality. The tool inclination angle shows a parabolic relation to the quality of the machined surface. After tool wear events, such as peeling-off of the tool coating, an increased surface roughness is observed.

Surface Quality for Rotary Ultrasonic Milling of Quartz Glass Employing Diamond Ball End Tool with Tool Inclination Angle

Nowadays, quartz glass is widely used in many industry fields. The machined surface quality is an important issue in the ultrasonic milling of quartz glass with diamond ball end tool. This paper analyzed the movement characteristics of the engaged cutting abrasive particles and investigated the effects of spindle rotation speed, feed speed, width of cut, and depth of cut on the machined surface topography and surface roughness. Also, comparisons of machining effects with and without ultrasonic were carried out. In general, application of ultrasonic vibration needs to cooperate with other process parameters to give play to the advantages of RUM, and ultrasonic function could not necessarily improve the formed surface. Comparing with conventional milling, reasonable selection of process parameters could decrease the machined surface roughness under the premise of achieving a high materials removal rate for RUM.

The Effect of Tool Orientation to Cut Geometry in Five-Axis Milling Using Analytical Boundary Simulation

One of the characteristics of five-axis milling is the tool can be oriented in any direction. It makes the tool orientation could be changed continuously during a free-form machining process. Consequently, the work to predict Cutter Workpiece Engagement (CWE) become more challenging. The existence of tool inclination angle and screw angle influence the profile of cut geometry. In this paper, an improved method to define the lower engagement point (LE-point) is presented. The algorithm was developed by taken into consideration the existence of inclination angle and screw angle. The extended method to calculate grazing point in swept envelope development was utilized to define LE-point. The developed model was successfully implemented to generate CWE data with various combination of tool orientation angle. From the test it was found that inclination angle gives significant effect to the location of LE-point.

Artificial immune algorithm implementation for optimized multi-axis sculptured surface CNC machining

This paper presents the results obtained by the implementation of an artificial immune algorithm to optimize standard multi-axis tool-paths applied to machine free-form surfaces. The investigation for its applicability was based on a full factorial experimental design addressing the two additional axes for tool inclination as independent variables whilst a multi-objective response was formulated by taking into consideration surface deviation and tool path time; objectives assessed directly from computer-aided manufacturing environment A standard sculptured part was developed by scratch considering its benchmark specifications and a cutting-edge surface machining tool-path was applied to study the effects of the pattern formulated when dynamically inclining a toroidal end-mill and guiding it towards the feed direction under fixed lead and tilt inclination angles. The results obtained form the series of the experiments were used for the fitness function creation the algorithm was about to sequentially evaluate. It was found that the artificial immune algorithm employed has the ability of attaining optimal values for inclination angles facilitating thus the complexity of such manufacturing process and ensuring full potentials in multi-axis machining modelling operations for producing enhanced CNC manufacturing programs. Results suggested that the proposed algorithm implementation may reduce the mean experimental objective value to 51.5%

Influence of tool inclination angle and cutting direction on long thin-walled part’s dimensional and geometric accuracy when high-speed ball end milling the heat-treated titanium alloy Ti–6Al–4 V

Thin-walled parts are often used in various industrial applications and due to their functional requirements, higher accuracies are generally desired. But due to their low stiffness characteristics, deformation and chatter problems are frequently encountered in their machining, thus resulting in poor accuracy. Moreover, due to 5-axes milling, which is usually required for finish machining of such parts, further complexities in the process are added and, consequently, achieving higher accuracy becomes more challenging. Therefore, in this study, the influence of tool inclination angle and feeding direction has been investigated on the resultant surface accuracy of thin cantilever shaped parts in finish milling conditions through experiments, finite element method simulations and theoretical discussions. Moreover, since work material’s microstructure and hardness also have key influence on its machinability, therefore, the effect of heat treatment state on resulting surface accuracy also has been explored. Three different titanium alloy, Ti–6Al–4 V specimens have been used. Two of the specimens were given solution treatment at 1050 ℃/1 h followed by aging at 550 ℃/4 h. One of the specimens after being solution treated was allowed to cool in air while the other was cooled in water to obtain different microstructure and hardness whereas the third specimen was used in as-received condition (casted). The three Ti–6Al–4 V specimens were machined at five different tool inclination angles (60°, 70°, 75°, 80°, and 85°) with two feeding directions (horizontal inwards and vertical inwards). Results have shown that the angle near the perpendicular to the surface i.e. 85° (5° away from the perpendicular) has lowest deformation value and also has better surface quality, which shows that the lowest effective cutting speed at this angle has helped in achieving higher accuracy. Moreover, among the cutting directions studied, vertical inward direction produces smoother surface due to its less pushing effect on the surface being cut as compared to horizontal inwards direction. And in terms of heat treatment state, the specimen which was cooled in air after being solution treated has produced better results for all cutting conditions studied, mainly attributed to fine homogenous lamellar α + β Ti–6Al–4 V structure achieved due to slow cooling rate of air. Analysis of variance using response surface methodology has been carried out to develop predictive model and to study the influence of each variable on the accuracy. The developed model has shown good accuracy when validated through additional experiments.

Geometrical Modeling of Tool-Workpiece Contact Zone and Chip Formation in Finish Ball End Milling Process with Tool Inclination Angles

The tool-workpiece contact zone is an important issue in the ball end milling process. This paper investigated the effects of tool inclination angles on the tool-workpiece contact zone, and variations of the cutting section area and perimeter with the increasing tilt and lead angles were also analyzed by geometrical modeling and measurement method for ball end milling process. The appropriate tool inclination angles, which could avoid the extrusion and friction between tool tip and the uncut materials, shorten the loading time on the cutting flute, and decrease the maximum cutting forces, could be preferentially selected according to the distribution characteristics of the tool-workpiece contact zone and the variations of the cutting section area and perimeter corresponding to various tool postures.

Finite Element Deformation Analysis of Long Thin Cantilever Shape Parts in High Speed Ball End Milling of Titanium Alloy Ti-6Al-4V with PCD Tools at Various Tool Inclination Angles

In this study the influence of tool inclination angle on deformation of thin wall cantilever shape part has been analyzed using finite element numerical simulations. Polycrystalline diamond, PCD tool has been chosen as a tool material in this study because PCD tool has given better results in terms of surface roughness, tool life and productivity in end milling of titanium alloy Ti-6Al-4V. Firstly, in this study, the effect of tool inclination angle on tool contact geometry, cutting speed and cutting forces has been discussed. Then, finite element numerical simulations (FEM) have been carried out in AdvantEdge® for the prediction of cutting forces with PCD tool at four different tilt angles viz. 70°, 75°, 80° and 85° and the results have been compared to the coated carbide tool. Then the maximum magnitude of the forces which occurred in tangential direction (FY) were input in the Abaqus® software as a load acting on the thin long cantilever part and deformation results were analyzed. Results show that PCD tool due to its high hardness, strength and better wear resistance produce lower cutting forces at all angles studied and at an angle near the perpendicular to the surface being machined both tools have lower values of the deformation. The FEM simulation results match well with the theoretical study as theoretical analysis also shows that at angles nearer to perpendicular to the surface being machined, the tool will have lower effective cutting speed & forces and hence proved as the key to achieving better accuracies for long thin wall parts.

Tool path planning and milling surface simulation for vehicle rear bumper mold

Sculptured surfaces have been widely used in various engineering applications. With the development of five-axis machining technology, five-axis machine tool has played a more and more important role in manufacturing sculptured surfaces. This article proposed a complete five-axis machining process planning for vehicle rear bumper mold. First, a numerical model considering tool inclination was developed to predict topography and surface roughness in ball-end milling processes. And then experimental verification was conducted. Second, according to the simulation results, it can be concluded that surface roughness decreases significantly with the tilt angle increasing from 0° to 5°. When the tilt angle is 10°, surface roughness gets the smallest value. What is more, surface roughness increases slightly from 10° to 30°. In the case of the permitted surface roughness, larger feed rate per tooth and the radial cutting depth can be chosen. Finally, a process strategy was made through the analysis of the mold in which the parameters were chosen according to the simulation results above.

High Speed Milling of Hardened Steel Convex Surface

This paper presents a contribution to hardened tool steel milling studies. High speed milling is largely utilized to substitute some EDM and polishing operations, mainly in hardened tool steel finishing. Tool path strategy may either enable good surface finish or contributes to generate high roughness values and poor surface finish. Tool inclination (angle between tool axis and workpiece surface) influences the system response to vibration. In this work, several milling experiments were performed in a circular convex AISI D6 hardened steel workpiece, having as input variables feed direction (upward and downward the circle) and tilt angle (tool inclination). The main results indicate that upward tool path presented mostly high roughness values which were also influenced by tool inclination. Downward tool path presented low roughness values and was less influenced by tool inclination. Upward tool path and positive tool inclination should be avoided because they presented roughness values incompatible to EDM process substitution.

Effect of tool Inclination Angle on the Elastic Deformation of Thin-walled Parts in Multi-axis Ball-end Milling

Thin-walled freeform surface parts are widely used in many fields, such as aerospace, automotive, etc. However, it is difficult to produce high quality thin-walled freeform parts in Numerical Controlled(NC) machining due to bending and twisting deformations induced by cutting forces. To overcome this problem, key issues are focused on twofold. First, the relationship between the milling force and the tool inclination angle in ball-end milling was established by using the theoretical and experimental methods. Second, the influence of tool inclination angle on the elastic deformation of thin-walled parts was analyzed by the finite element method. Finally, verification experiment was carried out in a 4-axis CNC machine tool, and the deformation values of the stainless steel test workpieces were measured by a coordinate measurement machine(CMM). The results show that when the tool inclination angles are 15° or 45°, both the milling force and the deformation of the test workpieces are the smallest.

Intelligent Optimization for Sculptured Surface CNC Tool-paths

This paper suggests the application of genetic algorithms for the intelligent generation of optimum sculptured surface CNC machining tool-paths. Two robust full quadratic mathematical models are developed relating the physical relation among machining surface deviation and resulting cutting time; quality objectives which are treated as conflicting ones. The independent variables are the tool inclination angles -lead and tilt- in the case of 5-axis machining and step-over engagement among subsequent XY passes; using a toroidal cutter. A Box-Behnken response surface design was established to prepare and conduct simulation experiments in a cutting-edge manufacturing software using a benchmark multivariable sculptured surface and a special multi-axis tool-path strategy. The genetic algorithm utilizes both models expressed as a common Pareto-based fitness function so that multi-objective optimization is achieved, yet; arriving at one optimum solution to ease the efforts of end-users and numerical control programmers. The methodology is validated by utilizing the genetic algorithm's recommendations for the settings of the machining parameters and the optimum tool-path simulation is performed to verify the operation.

MATHEMATICAL MODEL FOR CHIP GEOMETRY CALCULATION IN FIVE-AXIS MILLING

This paper presents the method to calculate the geometries of instantaneous chip in five-axis milling. The inclination angle changes in between two consecutive CC-points were taken into account in the calculation. In the first stage, the engagement angle, the axial depth of cut and cut width were determined through the mapping technique. The engagement point of the Work piece Coordinate System (WCS) was mapped to a Tool Coordinate System (TCS). In the second stage, the engagement angle and depth of cut, which were defined in the first stage were then used as a primary input to obtain the cut thickness and cut width. Two simulation tests have been presented to verify the ability of the proposed model to predict the cut geometry. The first tests revealed that the inclination angle makes the size of the cut thickness and cut width fluctuate. The cut width increased when the tool inclination angle increased. For the cut thickness, its magnitude was influenced by two effects, the orientation effect and the tooth path effect. The final result was a compromise between these two effects. In the second simulation test, the proposed model was successfully implemented to support the feedrate scheduling method.

Study of the Uncut Chip in 5 Axes Ball Nose End Milling for the Fourth Quadrant of the Tool Inclination

The ball nose end milling process, which use a ball nose cutter, is very complex and, generates a pronounced area variation of the cross section in the uncut chip. In this sense, the current paper looks into and assesses some aspects regarding the geometric simulation of the chip generating mechanism in 5 axes ball nose end milling. The influence of tool inclination, however, was not considered in the machining strategy, starting with the tool path program in CAM software, which allows the management of various ways of tool path generation, but cannot decide which one is the best. The present study advances, with minimal approximation, a geometrical method to establish the volume of the uncut chip and area variation of the cross section, obtained in 3D-CAD by four surfaces intersection [1]. Both rotations in 5 axes are considered for the tool and degree range is 0 to 30 for rotary axis A and 0 to-30 for rotary axis B (A+B-in fourth geometrical quadrant).

Effect of Cutting Conditions on Tool Wear in Driven Rotary Cutting of Maraging Steel

In this paper, driven rotary cutting of maraging steel was carried out and the influence on tool wear of difference cutting conditions was investigated. As cutting conditions, different coolant conditions, cutting speeds, circumferential velocity ratios, tool inclination angles, tool rotation directions and normal rake angles were tested. We found that as the coolant quantity decreased and cutting speed increased, the width of flank wear increased. It was also found that the circumferential velocity ratio, tool inclination angle, tool rotation direction and normal rake angle have optimal conditions that decrease wear. Optimal conditions were chosen, and a tool life test was carried out. As a result, driven rotary cutting was achieved with 11 or more times the tool life of conventional turning.

Influence of milling modes and tool postures on the milled surface for multi-axis finish ball-end milling

This work concentrated on the machined surface properties produced by the multi-axis ball-end milling process in order to enhance the high-performance application of multi-axis ball-end milling technology. The cutting speed of the engaged cutting edges and machining characteristics under various inclination angles were analyzed. The effects of inclination angles on the machined surface hardness, residual stresses, surface textures, topographies, and roughness were investigated under up-milling and down-milling conditions. Under up-milling condition, the machined surface hardness with regard to various tilt angles are larger than the ones under corresponding lead angles, and the variations of surface hardness with increasing lead angles are not apparent. In down-milling condition, double-peaks shape appears in the changing curve of surface hardness with increasing tilt and lead angles. The residual stresses present the overall trend of firstly increasing, then decreasing, and finally increasing with the increasing tilt angle from −45 to 45°. The surface residual stresses in both feed and cross-feed directions firstly decrease, and then increase with the increasing lead angle. Under both up-milling and down-milling, the compressive residual stresses significantly appear at the tool inclination angles near 0° due to extrusion action of the cutting edges close to tool tip and the low effective cutting speed. For down-milling condition, the surface textures are approximately parallel with the feed direction when using tilt angles with large values, and are approximately perpendicular to feed direction under varying lead angles. The apparent machining marks under negative tilt angles with relatively larger absolute values and obvious regular surface patterns corresponding to positive tilt angles could be observed. More surface pits and burrs and circular arc textures probably appear under small tilt angles and lead angles near 0°.

Influence of Tool Inclination on Micro-Ball-End Milling of Quartz Glass

Glass is difficult to machine due to its susceptibility to brittle fracture during machining. Tool tilt angle can exert a remarkable effect on the surface finish of glass in micro-ball-end milling. On the basis of a theoretical analysis and simulation by three-dimensional discrete element method, an optimal mathematical model is constructed for tool inclination, which is governed by edge radius of ball-nose of end-mill and cutting thickness. Corresponding experiments are conducted for model verification. The results show that different cutting thicknesses, cutter shapes, and spindle speeds have a considerable influence on machining mechanics of glass.

Experimental Research of Effective Cutting Speed Influence on Surface Roughness in Ball End Milling of C45 Material with Hardness 34 HRC

Machining of Complex Concave or Convex Surfaces Requires the Use of Ball End Milling Cutters. Obtaining the Expected Surface Quality Compete Various Technological Factors which should be Taken into Account. Following the Machining of the Surface with Different Inclination Angles between the Cutting Tool Axes and the Machined Surface, Significant Changes of the Surface Roughness have been Observed. Based on the Tests Performed, we can Determine the Range of the Tool Inclination Angle, which is the Best for the Surface Quality. we have also Made a Correlation between the Cutting Speeds, Inclination Angle of the Cutting Tool Toward the Machined Surface for an Obtained Surface Quality. the Presented Results are Based on Experimental Research in Industrial Conditions by Using CNC Machine Tools with 5 Axes. the Tests have been Performed on the C45 Material, Heat Treated to 34HRC.

Continuous Measurement-While-Drilling Utilizing Strap-Down Multi-Model Surveying System

In the oil drilling process, measurement-while-drilling system is usually used to provide real-time monitoring of the position and orientation of the bottom hole. Usually the bottom drill string attitude is measured on the condition that the drill string is static. Particularly, in rotary steerable drilling application, it is a challenging problem to accurately measure the spatial attitude (inclination, azimuth, and tool face) of the bottom drilling tool with the drill string rotating. A set of “strap-down” measurement system was developed in this paper, the triaxial accelerometer and triaxial fluxgate were installed near the bit, and real-time well deviation and azimuth can been measured. Laboratory experiments show that the dynamic solver methods will meet the project requirements. However, according to the drilling field tests, playback analysis on storage data of the underground measurement indicates that drill string vibration is the main reason for measurement errors. So, by setting a time window, the real-time measurement of the accelerometer and the flux gate signal are processed and analyzed, the movement patterns of the rotary drilling tool at the bottom were judged within the time window. Stick-slip phenomenon is utilized to improve the measurement accuracy and to reduce the impact of lateral vibration of the drilling string on the measurement system. We could take advantage of stick-slip phenomenon because of it cannot be avoided completely, although it should be avoided in order to improve the drilling string operating life. Simulation results showed that recommended dynamic survey approach could effectively enhance measurement precision, and deduce effect of vibration on resolve results.