scholarly journals Mechanics and Dynamics of Ball End Milling

1998 ◽  
Vol 120 (4) ◽  
pp. 684-692 ◽  
Author(s):  
Y. Altıntas¸ ◽  
P. Lee
Keyword(s):  
Time Domain ◽  
Transfer Functions ◽  
End Milling ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Milling Process ◽  
Body Motion ◽  
Ball End Milling ◽  
Cutting Model ◽  
End Milling Process

Mechanics and dynamics of cutting with helical ball end mills are presented. The helical ball end mill attached to the spindle is modelled by orthogonal structural modes in the feed and normal directions at the tool tip. For a given cutter geometry, the cutting coefficients are transformed from an orthogonal cutting data base using an oblique cutting model. The three dimensional swept surface by the cutter is digitized using the true trochoidal kinematics of ball end milling process in time domain. The dynamically regenerated chip thickness, which consists of rigid body motion of the tooth and structural displacements, is evaluated at discrete time intervals by comparing the present and previous tooth marks left on the finish surface. The process is simulated in time domain by considering the instantaneous regenerative chip load, local cutting force coefficients, structural transfer functions and the geometry of ball end milling process. The proposed model predicts cutting forces, surface finish and chatter stability lobes, and is verified experimentally under both static and dynamic cutting conditions.

Shear and Friction Processes in Intermittent Cutting

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1401-1407
Author(s):  
Young Moon Lee ◽  
Seung Han Yang ◽  
Seung Il Chang
Keyword(s):  
End Milling ◽  
Chip Thickness ◽  
Shear Plane ◽  
Milling Process ◽  
Oblique Cutting ◽  
Shear Process ◽  
Cutting Processes ◽  
Cutting Model ◽  
Intermittent Cutting ◽  
End Milling Process

In intermittent cutting processes, characterized by the use of rotating tools, the undeformed chip thickness varies periodically according to the phase change of tool. Although many studies have already concentrated on intermittent cutting processes, there has been no previous analysis of the shear and friction processes. In the current study, an up-end milling process is transformed into an equivalent oblique cutting process. The varying undeformed chip thicknesses and cutting forces in the up-end milling process are thus replaced with the equivalent average ones. As a result, the shear process in shear plane and the chip-tool friction process of intermittent cutting are analyzed using the equivalent oblique cutting model. The validity of the proposed analysis was verified based on two sets of cutting tests i.e. up-end milling and equivalent oblique cutting tests.

A Mechanistic Cutting Force Model for 3D Ball-end Milling

2000 ◽  
Vol 123 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Hsi-Yung Feng ◽  
Ning Su
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
End Milling ◽  
Chip Thickness ◽  
Milling Process ◽  
Force Model ◽  
Cutting Force Model ◽  
Ball End Milling ◽  
End Milling Process ◽  
Force Relationship

This paper presents an improved mechanistic cutting force model for the ball-end milling process. The objective is to accurately model the cutting forces for nonhorizontal and cross-feed cutter movements in 3D finishing ball-end milling. Main features of the model include: (1) a robust cut geometry identification method to establish the complicated engaged area on the cutter; (2) a generalized algorithm to determine the undeformed chip thickness for each engaged cutting edge element; and (3) a comprehensive empirical chip-force relationship to characterize nonhorizontal cutting mechanics. Experimental results have shown that the present model gives excellent predictions of cutting forces in 3D ball-end milling.

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

2016 ◽  
Vol 693 ◽  
pp. 788-794
Author(s):  
Xiao Xiao Chen ◽  
Jun Zhao
Keyword(s):  
Contact Zone ◽  
Measurement Method ◽  
End Milling ◽  
Milling Process ◽  
Ball End Milling ◽  
Geometrical Modeling ◽  
Section Area ◽  
Inclination Angles ◽  
Area And Perimeter ◽  
End Milling Process

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.

Intelligent Monitoring and Prediction of Surface Roughness in Ball-End Milling Process

2011 ◽  
Vol 121-126 ◽  
pp. 2059-2063 ◽  
Author(s):  
Somkiat Tangjitsitcharoen ◽  
Angsumalin Senjuntichai
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Prediction Accuracy ◽  
End Milling ◽  
Milling Process ◽  
Ball End Milling ◽  
Roughness Model ◽  
Force Ratio ◽  
Tool Diameter ◽  
End Milling Process

In order to realize the intelligent machines, the practical model is proposed to predict the in-process surface roughness during the ball-end milling process by utilizing the cutting force ratio. The ratio of cutting force is proposed to be generalized and non-scaled to estimate the surface roughness regardless of the cutting conditions. The proposed in-process surface roughness model is developed based on the experimentally obtained data by employing the exponential function with five factors of the spindle speed, the feed rate, the tool diameter, the depth of cut, and the cutting force ratio. The prediction accuracy and the prediction interval of the in-process surface roughness model at 95% confident level are calculated and proposed to predict the distribution of individually predicted points in which the in-process predicted surface roughness will fall. All those parameters have their own characteristics to the arithmetic surface roughness and the surface roughness. It is proved by the cutting tests that the proposed and developed in-process surface roughness model can be used to predict the in-process surface roughness by utilizing the cutting force ratio with the highly acceptable prediction accuracy.

Generalized Mechanistic Force System Model of Ball-End Milling for Sculpture Surface Machining

2001 ◽  
Author(s):  
Ismail Lazoglu
Keyword(s):  
End Milling ◽  
Mechanistic Model ◽  
Milling Process ◽  
Force System ◽  
Workpiece Surface ◽  
Surface Machining ◽  
Ball End Milling ◽  
End Milling Process ◽  
Validation Experiments ◽  
Good Agreement

Abstract In this paper, a new mechanistic model is developed for the prediction of cutting force system in ball-end milling process. The key feature of the model includes the ability to calculate the workpiece / cutter intersection domain automatically for a given cutter location (CL) file, cutter and workpiece geometries. Moreover, an analytical approach is used to determine the instantaneous chip load and cutting forces. The model also employs a Boolean approach for given cutter, workpiece geometries, and the CL file in order to determine the surface topography and scallop height variations along the workpiece surface which can be visualized in 3-D. Some of the typical results from the model validation experiments performed on Ti-6A1-4V are also reported in the paper. Comparisons of the predicted and measured forces as well as the surface topographies show good agreement.

Analytical Prediction of Stability Lobes in Ball End Milling

1999 ◽  
Vol 121 (4) ◽  
pp. 586-592 ◽  
Author(s):  
Y. Altıntas¸ ◽  
E. Shamoto ◽  
P. Lee ◽  
E. Budak
Keyword(s):  
Cutting Force ◽  
End Milling ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Transformation Method ◽  
Quadratic Equation ◽  
Analytical Prediction ◽  
Force Coefficient ◽  
Ball End Milling ◽  
Stability Lobes

The paper presents an analytical method to predict stability lobes in ball end milling. Analytical expressions are based on the dynamics of ball end milling with regeneration in the uncut chip thickness, time varying directional factors and the interaction with the machine tool structure. The cutting force coefficients are derived from orthogonal cutting data base using oblique transformation method. The influence of cutting coefficients on the stability is investigated. A computationally efficient, an equivalent average cutting force coefficient method is developed for ball end milling. The prediction of stability lobes for ball end milling is reduced to the solution of a simple quadratic equation. The analytical results agree well with the experiments and the computationally expensive and complex numerical time domain simulations.

Dynamic cutting force prediction for micro end milling considering tool vibrations and run-out

2018 ◽  
Vol 233 (7) ◽  
pp. 2248-2261 ◽  
Author(s):  
Xuewei Zhang ◽  
Tianbiao Yu ◽  
Wanshan Wang
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
End Milling ◽  
Chip Thickness ◽  
Milling Process ◽  
Force Model ◽  
Dynamic Cutting Force ◽  
Micro End Milling ◽  
Tool Vibrations ◽  
End Milling Process

An accurate prediction of cutting forces in the micro end milling, which is affected by many factors, is the basis for increasing the machining productivity and selecting optimal cutting parameters. This paper develops a dynamic cutting force model in the micro end milling taking into account tool vibrations and run-out. The influence of tool run-out is integrated with the trochoidal trajectory of tooth and the size effect of cutting edge radius into the static undeformed chip thickness. Meanwhile, the real-time tool vibrations are obtained from differential motion equations with the measured modal parameters, in which the process damping effect is superposed as feedback on the undeformed chip thickness. The proposed dynamic cutting force model has been experimentally validated in the micro end milling process of the Al6061 workpiece. The tool run-out parameters and cutting forces coefficients can be identified on the basis of the measured cutting forces. Compared with the traditional model without tool vibrations and run-out, the predicted and measured cutting forces in the micro end milling process show closer agreement when considering tool vibrations and run-out.

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