Cutting Force Prediction of Ball End Milling Based on Fully Voxel Representation of Cutting Edge and Instantaneous Workpiece Shape

2017 ◽  
Author(s):  
Isamu Nishida ◽  
Ryuma Okumura ◽  
Ryuta Sato ◽  
Keiichi Shirase
Keyword(s):  
Cutting Force ◽  
End Milling ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Surface Shape ◽  
Uncut Chip Thickness ◽  
Ball End Milling ◽  
Voxel Model ◽  
Voxel Representation ◽  
Milling Forces

A new cutting force simulator has been developed to predict cutting force in ball end milling. This new simulator discretely calculates uncut chip thickness based on a fully voxel representation of the cutting edge and instantaneous workpiece shape. Previously, a workpiece voxel model was used to calculate uncut chip thickness under a complex change of workpiece shape. Using a workpiece voxel model, uncut chip thickness is detected by extracting the voxels removed per cutting edge tooth for the amount of material fed into the cutting edge. However, it is difficult to define the complicated shape of a cutting edge using the workpiece voxel model; the shape of the cutting edge must be defined by a mathematical expression. It is also difficult to model the voxels removed by the cutting edge when the tool posture is non-uniformly changed. We therefore propose a new method to detect uncut chip thickness, one in which both the cutting edge and the instantaneous workpiece shape are fully represented by a voxel model. Our proposed method precisely detects uncut chip thickness at minute tool rotational angles, making it possible to detect the uncut chip thickness between the complex surface shape of the workpiece and the particular shape of the cutting edge. To validate the effectiveness of our proposed method, experimental 5-axis milling tests using a ball end mill were conducted. Estimated milling forces for several tool postures were found to be in good agreement with the measured milling forces. Results from the experimental 5-axis milling validate the effectiveness of our proposed method.

Cutting Force Simulation in Minute Time Resolution for Ball End Milling Under Various Tool Posture

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Isamu Nishida ◽  
Ryuma Okumura ◽  
Ryuta Sato ◽  
Keiichi Shirase
Keyword(s):  
Cutting Force ◽  
End Milling ◽  
Chip Thickness ◽  
Cutting Edge ◽  
New Method ◽  
Uncut Chip Thickness ◽  
Tool Posture ◽  
Voxel Model ◽  
Five Axis ◽  
Milling Forces

A new cutting force simulator has been developed to predict cutting force in ball end milling. In this simulator, uncut chip thickness is discretely calculated based on fully voxel models representing both cutting edge and instantaneous workpiece shape. In the previous simulator, a workpiece voxel model was used to calculate uncut chip thickness under a complex change of workpiece shape. Using a workpiece voxel model, uncut chip thickness is detected by extracting the voxels removed per cutting tooth for the amount of material fed into the cutting edge. However, it is difficult to define the complicated shape of cutting edge, because the shape of cutting edge must be defined by mathematical expression. It is also difficult to model the voxels removed by the cutting edge when tool posture is nonuniformly changed. Therefore, a new method to detect uncut chip thickness is proposed, one in which both cutting edge and instantaneous workpiece shape are fully represented by a voxel model. Our new method precisely detects uncut chip thickness at minute tool rotation angles, making it possible to detect the uncut chip thickness between the complex surface shape of the workpiece and the particular shape of the cutting edge. To validate the effectiveness of our new method, experimental five-axis milling tests using ball end mill were conducted. Estimated milling forces for several tool postures were found to be in good agreement with the measured milling forces. Results from the experimental five-axis milling validate the effectiveness of our new method.

Voxel Based Cutting Force Simulation of Ball End Milling Considering Cutting Edge Around Center Web

2018 ◽  
Author(s):  
Isamu Nishida ◽  
Takaya Nakamura ◽  
Ryuta Sato ◽  
Keiichi Shirase
Keyword(s):  
Cutting Force ◽  
End Milling ◽  
Chip Thickness ◽  
Previous Method ◽  
Cutting Edge ◽  
Force Model ◽  
End Mill ◽  
Uncut Chip Thickness ◽  
Ball End Mill ◽  
Tool Rotation

A new method, which accurately predicts cutting force in ball end milling considering cutting edge around center web, has been proposed. The new method accurately calculates the uncut chip thickness, which is required to estimate the cutting force by the instantaneous rigid force model. In the instantaneous rigid force model, the uncut chip thickness is generally calculated on the cutting edge in each minute disk element piled up along the tool axis. However, the orientation of tool cutting edge of ball end mill is different from that of square end mill. Therefore, for the ball end mill, the uncut chip thickness cannot be calculated accurately in the minute disk element, especially around the center web. Then, this study proposes a method to calculate the uncut chip thickness along the vector connecting the center of the ball and the cutting edge. The proposed method can reduce the estimation error of the uncut chip thickness especially around the center web compared with the previous method. Our study also realizes to calculate the uncut chip thickness discretely by using voxel model and detecting the removal voxels in each minute tool rotation angle, in which the relative relationship between a cutting edge and a workpiece, which changes dynamically during tool rotation. A cutting experiment with the ball end mill was conducted in order to validate the proposed method. The results showed that the error between the measured and predicted cutting forces can be reduced by the proposed method compared with the previous method.

Prediction of Ball End Milling Forces

1996 ◽  
Vol 118 (1) ◽  
pp. 95-103 ◽  
Author(s):  
G. Yu¨cesan ◽  
Y. Altıntas¸
Keyword(s):  
Cutting Forces ◽  
End Milling ◽  
Chip Thickness ◽  
Cutting Conditions ◽  
Analytic Representation ◽  
Rake Face ◽  
Uncut Chip Thickness ◽  
Ball End Milling ◽  
Helical Flute ◽  
Milling Forces

Mechanics of milling with ball ended helical cutters are modeled. The model is based on the analytic representation of ball shaped helical flute geometry, and its rake and clearance surfaces. It is assumed that friction and pressure loads on the rake face are proportional to the uncut chip thickness area. The load on the flank contact face is concentrated on the in cut portion of the cutting edge. The pressure and friction coefficients are identified from a set of slot ball end milling tests at different feeds and axial depth of cuts, and are used to predict the cutting forces for various cutting conditions. The experimentally verified model accurately predicts the cutting forces in three Cartesian directions.

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.

A HIGHER FIDELITY MODELING OF THE CUTTING EDGE OF BALL-END MILLING TOOL

2011 ◽  
Vol 10 (01) ◽  
pp. 101-108 ◽  
Author(s):  
XIULIN SUI ◽  
IMRE HORVATH ◽  
JIATAI ZHANG ◽  
PING ZHANG
Keyword(s):  
End Milling ◽  
Milling Process ◽  
Cutting Edge ◽  
Ball End Milling ◽  
Machining Conditions ◽  
Milling Tool ◽  
Efficient Planning ◽  
Pilot Implementation ◽  
Physical Changes ◽  
Milling Forces

Ball-end milling tools have been widely used in machining of complex freeform surfaces. The precision and efficiency of ball-end milling process can be improved by an accurate modeling of the tools, the tools' paths and the machining conditions. However, only rough geometric models have been applied so far, which do not consider the machining conditions and the physical changes. To achieve the best results, an accurate modeling of the cutting edge and the physical behavior of the entire cutter is needed. This paper proposes an articulated model that enumerates both the geometric characteristics and the physical effects acting on the cutting edge-segment of a ball-end milling cutter. The model considers the deformations caused by the milling forces, vibration, spindle eccentricity, together with thermal deformation and wear of the cutter. The mathematical description of the behavior has been transferred into a computational model. The pilot implementation has been tested in a practical application. The first findings show that the proposed theoretical model and implementation provide sufficiently precise information about the behavior of the cutter in virtual simulations; hence it can be the basis of a fully fledged and more efficient planning of milling processes.

Single Edge Cutting Phenomenon and Instantaneous Uncut Chip Thickness Model of Micro-Ball-End Milling

2011 ◽  
Vol 4 (4) ◽  
pp. 1387-1393 ◽  
Author(s):  
Zhenyu Han ◽  
Xiang Zhang ◽  
Yazhou Sun ◽  
Hongya Fu ◽  
Yingchun Liang
Keyword(s):  
End Milling ◽  
Chip Thickness ◽  
Single Edge ◽  
Uncut Chip Thickness ◽  
Ball End Milling ◽  
Instantaneous Uncut Chip Thickness

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.

Two-Step Identification of Instantaneous Cutting Force Coefficients and Cutter Runout

2014 ◽  
Vol 887-888 ◽  
pp. 1179-1183 ◽  
Author(s):  
Hong Yan Hao ◽  
Wen Cheng Tang ◽  
Bao Sheng Wang
Keyword(s):  
Cutting Force ◽  
End Milling ◽  
Chip Thickness ◽  
Key Factors ◽  
Cutter Runout ◽  
Cutting Force Coefficients ◽  
Force Coefficients ◽  
Instantaneous Cutting Force Coefficients ◽  
Identification Approach ◽  
Milling Forces

Cutting force coefficients and cutter runout parameters are the key factors for accurate prediction of instantaneous milling forces. A new two-step identification method is presented to calibrate them in end milling. Based on analyzing effects of cutter runout on milling forces, a method of extracting nominal milling forces from measured milling forces is proposed. By calibrating average cutting force coefficients and corresponding average chip thickness, an approach to evaluate the instantaneous cutting force coefficients is proposed. Then, an iterative method is presented to identify cutter runout, and the procedure is also given in detail. Milling tests are performed to test the proposed method, and validity of the identification approach is proved by a good agreement between predicted results and experimental results.

An Approach to Modeling Cutting Forces in Five-Axis Ball-End Milling of Curved Geometries Based on Tool Motion Analysis

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Guo Dongming ◽  
Ren Fei ◽  
Sun Yuwen
Keyword(s):  
Motion Analysis ◽  
Cutting Forces ◽  
End Milling ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Axis Orientation ◽  
Undeformed Chip Thickness ◽  
Ball End Milling ◽  
Tool Motion ◽  
Five Axis

The prediction of five-axis ball-end milling forces is quite a challenge due to difficulties of determining the underformed chip thickness and engaged cutting edge. To solve these concerns, this paper presents a new mechanistic model of cutting forces based on tool motion analysis. In the model, for undeformed chip thickness determination, an analytical model is first established to describe the sweep surface of cutting edge during the five-axis ball-end milling process of curved geometries. The undeformed chip thickness is then calculated according to the real kinematic trajectory of cutting edges under continuous change of the cutter axis orientation. A Z-map method is used to verify the engaged cutting edge and cutting coefficients are subsequently calibrated. The mechanistic method is applied to predict the cutting force. Validation tests are conducted under different cutter postures and cutting conditions. The comparison between predicted and measured values demonstrates the applicability of the proposed prediction model of cutting forces.

Modeling of Ball-End Milling Forces With Cutter Axis Inclination

1999 ◽  
Vol 122 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Ismail Lazoglu ◽  
Steven Y. Liang
Keyword(s):  
End Milling ◽  
Chip Thickness ◽  
Helix Angle ◽  
Force Model ◽  
Ball End Mill ◽  
Ball End Milling ◽  
Model Predictions ◽  
Milling Forces ◽  
Analytical Force Model ◽  
Convolution Method

In the machining of sculpture surfaces with ball-end mill, the cutter axis or workpiece is often inclined to generate an admissible orientation. This paper primarily presents an enhanced cutting force model for ball-end milling with cutter axis inclination. It involves the kinematic reasoning of cutting edge geometry, local helix angle and average chip thickness followed by the analysis of effects of axis inclination in the contact zone between cutter and workpiece. Thereupon, development of the analytical force model for inclined-axis machining is achieved using cutter angle domain convolution method. Experimental evaluation of the model is discussed, and experimental results and model predictions under various cutting conditions are compared in the frequency as well as in the angular domain. [S1087-1357(00)70601-0]

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