Ball-end Milling Cutter Research Articles

Models of the relationship among geometric parameters and anti-friction mechanism of micro-texture ball-end milling cutter

Researches on the effect of the micro-texture on the cutting performance and the life of cutters are mostly aimed at turning cutters, but there are few researches on the ball-end milling cutter. On the basis geometry of the micro-texture, the distribution and the relationship among the geometric parameters of micro-pits are studied. A mechanical characteristic model of machining titanium alloy with the micro-texture ball-end milling cutter is established. Optimal parameters of the micro-texture are determined by the simulation. By the test of machining the titanium alloy with the micro-texture ball-end milling cutter, anti-friction properties, the influence laws of the micro-texture diameter on forces, and area occupancy on the tool wear are studied. This article provides a theoretical reference for determining the location of the micro-texture on ball-end milling cutter and selecting texture parameters reasonably. The anti-friction mechanism of the micro-texture is revealed by the theory, which provides a theoretical basis for the efficient processing of titanium alloy.

Research on Modeling and Simulation of Surface Topography Obtained by Trochoidal Milling Mode with Ball End Milling Cutter

Research on Modeling and Simulation of Surface Topography Obtained by Trochoidal Milling Mode with Ball End Milling Cutter

Dynamic response analysis of a ball-end milling cutter and optimization of the machining parameters for a ruled surface

Cutter displacements and deflections induce a significant amount of surface error in machined thin-walled parts and are a major obstacle to achieving higher productivity in a five-axis milling oper...

Comparison of Theoretical and Real Surface Roughness in Case of Ball-End Milling

In case of free form surface milling the quality of the manufacturing is described by the accuracy of the shape and the surface roughness. The 3D surface finishing milling by ball-end milling cutter is one of the most often used machining technologies. In case of ball-end milling the surface roughness can be described theoretically based on the tool diameter and the density of the tool path, but the experience shows than other parameters have effect on the surface roughness. In the article the effect of the different cutting parameters, like feed (fz), depth of cut (ap) and width of cut (ae), is presented in case of plane surface, and the surface roughness is compared with the theoretical roughness, and an estimation method is presented.

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.

Repairing parts from nickel base material alloy by laser cladding and ball end milling

Due to rising costs of raw material, companies of the aerospace industry increasingly seek to repair components of aircraft engines instead of replacing them. Particularly the clad repair of turbine blades made of high strength nickel-base alloys with directionally solidified or single crystalline structure is a difficult issue, especially due to high requirements regarding the conditions of the final part surface. The present work deals with the question whether the prediction of surface and subsurface conditions, e.g. surface topography and residual stresses, is possible after repairing the inhomogeneous nickel-base alloy Rene 80. For this purpose, laser deposition cladding is applied for the polycrystalline Rene 80, using the filler material Rene 142. In the following re-contouring process, the claddings are milled with a ball end mill cutter. The influence of the inhomogeneous base material and the shape of the clad on the cutting forces as well as the final part surface are experimentally investigated. Superficial residual stresses are measured and evaluated. The cutting forces and the final surface reveal characteristic variations in the area of the material deposition and the dendrites. A geometric process simulation shows that the prediction of cutting forces and surface conditions for the polycrystalline material is only possible to some extent.

Error compensation model considering tool wear in milling difficult to cut materials

In this paper, error compensation considering tool wear is studied to improve machining precision of difficult-to-cut material in milling process. First, an error model considering tool wear in milling process is established based on the relationship between the position angle and the radius of the section circle of ball-end milling cutter, and the established error model is solved and verified. Then, based on the verified error model, a new error compensation method based on a scale division idea is proposed to determine the required compensation value and generate the compensated tool path by tracing the initial tool path and tool wear deviations. Based on the above error compensation method, the detailed compensated processes for a plane, cylindrical surface and sculptured surface are analysed and an off-line error compensation software is developed by using Visual C++ programming tool. Finally, experimental tests performed with stainless steel 1Cr18Ni9Ti and cemented carbide cutters, are used to validate the reliability of the proposed error compensation method in milling operations. Experimental results show that the proposed error compensation method can reduce machining error and improve machining surface quality.

Surface Quality Prediction in Case of Steep Free Form Surface Milling

The machining of free form surfaces is a current and important issue in die and mould industry. Beside the complex geometry, an accurate and productive machining and good surface quality are needed. The finishing milling carried out by a ball-end or toroid milling cutter defines the surface quality, which is characterized by the surface roughness and the tool path trace. The surface quality is defined by the properties of the milling cutter, the type of surface and its position, as well as the cutting parameters. This article focuses on the z-level milling of steep surfaces by 2.5D milling strategy. The importance of the different elements of the tool path is presented, the effect of cutting parameters is investigated, and a formula to predict the surface roughness is suggested.

Error Analysis in Surfaces Reconstruction by Fitting and Interpolation Technique

Error between surfaces is the measurement to give us information how similar or different they are. Moreover, since the data associated with error between two matching surfaces are too huge and further need to be filtered into meaningful information. This research shows the suitable ways to represent error, to achieve data reduction and how detailed. Surfacerepresentations that may then be used as a part of many applications in engineering, clinic, virtual and other CAD applications. The statistical tools analysis of error has been developed to provide effective visual inputs that the designer can interpret of meaningful information. The comparison between two matching surfaces was done by using the differences in elevation techniquesthat called distance error between surfaces. A comparison has been made between the two adopted techniques of surface generation (fitting and interpolation) depending on several standard functions (sine-cosine functions, exponential functions and power functions), where the two techniques (fitting and interpolation) have been applied to analyze the representing error statistically. Then the design results have been implemented in manufacturing three of these surfaces using three axis vertical CNC milling machine tool with ball end mill cutter. By applying the proposed surface models, the similarity factor was found to be ranged between 84.86% for one of the models to 100% for other models that are reconstructed by the adopted fitting and interpolating techniques.

Orthogonal Variable Thickness Cutting Modeling of Surface Milling and Physical Fields Simulation

When milling the complex surface with the ball-end milling cutter, the cutting thickness always changes in ball-end milling process. At present, many milling models are actually simplified with unchanged cutting thickness, which ignores the ball-end milling cutting with complex tool-work piece relationship. According to the characteristics of the ball-end milling, orthogonal variable thickness cutting model is established based on the study of three-dimensional contact relationship of tool-work piece. The simulation of the stress field and the temperature field in hardened steel Cr12MoV orthogonal variable thickness cutting process is conducted, and comparative analysis of stress and temperature field distribution of high-speed milling and conventional milling is made. The cutting model of orthogonal variable thickness cutting can reflect the characteristics of surface milling accurately, which can be further used in the study of changing characteristics of physical fields and the optimization of cutting and tool parameters to improve the machining efficiency and quality.

Effect of Tool Wear on Surface Qualities in Milling of TC4

Tool wear is easy occurred in titanium alloy milling process which will affect the surface quality. Surface roughness and surface morphology as an important index to describe and evaluate the surface quality has a great influence on service performance. Therefore, the study on the effect of tool wear on surface qualities is important to improve the surface integrity of titanium alloy parts. Cutting radius of ball-end milling cutter is solved to analyze the effect of tool wear on the cutting radius. The tool wear and the surface qualities of TC4 are achieved through wear experiment. And then the influence law of tool wear on surface qualities and chip morphology are analyzed. The results show that surface roughness value decrease firstly and then increases and that chip morphology with flank wear increase from the unit chip to the serrated chip.

Analysis Method for Surface Topography Model in High Speed Milling Hardened Steel

During high speed milling hardened steel, the problem that tool vibration reducing machining surface quality causes led to a research for the influence characteristics of milled surface topography through high speed milling experiment. To determine the formation condition of milled surface topography, using displacement increment of origin of tool coordinate system which is caused by the milling cutter vibration and installation error, modifies the cutting motion trajectory. Based on the tool-workpiece contact relationship and the cutting layer parameters of contact points on two teeth, the residual units of machined surface are established, thereby proposing a solution method for the deformation and distribution characteristic of residual units under the overhanging volume and the vibration. Therefore, the milled surface topography of cutting hardness steel with high speed ball-end milling cutter is revealed to bring out a striking contrast between the simulation and experiment of milled surface topography of hardness steel.

Design and fabrication of double-circular-arc torus milling cutter

Focusing on the feed rate limitation and high cutting force of regular torus milling cutter in machining dies, a double-circular-arc torus milling cutter is designed and fabricated in this work. The geometric characteristics, cutting force, and milling process of the milling cutter are analyzed and presented. The mathematical models of the cutting edge and radius of the main-circular-arc cutting edge are built. To ensure the cutting performance of the milling cutter, a grinding method combining theory, simulation, fabrication, and test is proposed for the fabrication of the milling cutter. The grinding model is built through coordinate transformation. The evaluation of grinding accuracy is proposed. The milling cutter is shaped on a five-axis NC grinding machine, and its accuracy is tested by a tool test center. The test results show the feasibility of the grinding process and the grinding accuracy is ensured. To verify the cutting performance of the proposed double-circular-arc torus milling cutter, milling experiments are conducted. The cutting force and surface roughness of ball-end milling cutter, regular torus milling cutter, and two double-circular-arc torus milling cutters are measured and compared. It is shown that the double-circular-arc torus milling cutters can generate low cutting force and low surface roughness.

Study on Simulation of Machining Deformation and Experiments for Thin-walled Parts of Titanium Alloy

Deformation problems are main factors affecting the precision of machining the thin-walled parts. This paper focuses on the thin-walled parts of titanium alloy that is the difficult-to-machine material, based on the analysis of deformation characteristics and force, the milling force mathematical model of the ball-end milling cutter was established. On the basis of the 3D milling model of thin-walled parts of titanium alloy, the deformation regularity and cutting force variations were analyzed with the finite element simulation method. Through the experiments of machining thin-walled parts, the cutting force model was verified. The experiments results and simulations results match well. The work provides an effective basis for further study on the control of machining deformation of thin-wall parts of titanium alloy.

Modelling and prediction of tool wear using LS-SVM in milling operation

This article focuses on the least squares support vector machine (LS-SVM), which can solve highly nonlinear and noisy black-box modelling problems, and tool wear model based on LS-SVM for ball-end milling cutter is established by considering the joint effect of machining conditions. In the established model, machining parameters and position parameter of ball-end cutter are considered as input and the output of the proposed model is tool wear of cutting edge position. The experimental measured tool wear is used to train the established model, and the interconnection relationship between input and output parameters is determined after training. The analysis and comparison of predicted performance are given by taking different tuning parameters and data regularisation. Some interesting analysis results are deduced from the established LS-SVM-based tool wear model. In order to further show the effectiveness of LS-SVM-based tool wear model, the verified comparison between LS-SVM-based and ANN-based model is given. Finally, the discussion of interactional effect of machining parameters on tool wear estimation is used to evaluate prediction performance of LS-SVM-based model. The verification shows that the LS-SVM-based tool wear model is suitable to predict tool wear at certain range of cutting conditions in milling operation.

Tool Path Generation, for Complex Surface Machining, Using Point Cloud Data

This paper gives a detailed explanation of the project, related to reverse engineering, which was conducted by the authors of this paper. The project was based on direct machining, which is done by generating efficient tool paths directly from point cloud data, stored in STL format. The primary objective was to achieve high efficiency in the machining of free-form surface geometries, having complex machining areas. Reverse engineering traditionally involves surface fitting. However, it has several drawbacks. To overcome these drawbacks, the concept of direct machining is used. This skips the surface fitting process and consists of three main steps: digitizing, tool path generation and machining. Therefore, an algorithm to generate tool paths for direct machining was developed. The algorithm works for three-axis milling, using a ball-end mill cutter. It includes dividing the surface into ranges and generating B-spline curves which are best fit curves within each range. These curves are the required tool paths. A few case studies have also been conducted using this algorithm.

Modeling/analysis of four-half axis machine tool via modified denavit-hartenberg notation

Four-half axis and five-axis machine tools have five moving members (X, Y, Z, A, and B). Four-half axis systems cannot simultaneously operate the B axis with translational or rotational axes, thus limiting tool machining ability and complicating NC codes. This study employs modified Denavit-Hartenberg notation to model four-half axis machine tool kinematics and obtain corresponding ability matrixes. NC data equations for the A, B, X, Y, and Z axes with respect to the workpiece frame are derived by inverse kinematics. Machine tool active parameters and workpiece home position are simultaneously measured by using a ball-end milling cutter as a measuring probe.

Based on the Titanium Alloy Milling Forces Modeling and Simulation Study

A common mechanical model of ball-end milling cutter is analyzed in this paper, and take advantage of the orthogonal experiment method to make experiment of milling to identify the milling force coefficients with the titanium alloy material as the test object.Then put the coefficients in the mechanical model of ball to use MATLAB software to predict the milling force. The results of experiment and results of simulation are basically identical, it shows that the mechanics model of ball milling is proved to be correct.

Micro Ball End Milling of Nickel-Based Alloy for Laval Nozzle

The performance of the micro nozzle is determined primarily by its machined surface topology and geometric profile. A circular cross-section micro-Laval nozzle is modeled and studied by using numerical simulation in this paper. The real residual height and residual area of machined nozzle surface with ball-end milling cutter are proposed. A micro-Laval nozzle was machined successfully. It is found that the ball end milling cutter with large radius is suitable for finishing operations in the viewpoint of nozzle performance. Moreover, the serial process of drilling and milling has been proved by experiments with which both high-level machining accuracy and performance can meet the nozzle requirement.

Parametric Design of Ball-End Milling Tools for High Speed Milling

Ball-end milling cutter is widely used in machining complex surface parts , and it is need to select a reasonable geometric parameters of the milling cutter for different work piece materials and shapes and cutting parameters. This article is based on UG secondary development technology to develop the Multi-blade ball-end milling cutter parametric design system, it is automatic, fast and efficient to build all kinds of parameters of double, three and four blades ball-end milling cutter model required for user.