scholarly journals A combination method of the theory and experiment in determination of cutting force coefficients in ball-end mill processes

2015 ◽  
Vol 2 (4) ◽  
pp. 233-247 ◽  
Author(s):  
Yung-Chou Kao ◽  
Nhu-Tung Nguyen ◽  
Mau-Sheng Chen ◽  
Shyh-Chour Huang

Abstract In this paper, the cutting force calculation of ball-end mill processing was modeled mathematically. All derivations of cutting forces were directly based on the tangential, radial, and axial cutting force components. In the developed mathematical model of cutting forces, the relationship of average cutting force and the feed per flute was characterized as a linear function. The cutting force coefficient model was formulated by a function of average cutting force and other parameters such as cutter geometry, cutting conditions, and so on. An experimental method was proposed based on the stable milling condition to estimate the cutting force coefficients for ball-end mill. This method could be applied for each pair of tool and workpiece. The developed cutting force model has been successfully verified experimentally with very promising results. Highlights By investigation of the stable cutting conditions in milling process, the linear function of average cutting force and feed per flute was successfully verified. A combined theoretical-experimental method was proposed with an effective model for the determination of cutting force coefficients in ball-end mill process.

Author(s):  
Han Ul Lee ◽  
Dong-Woo Cho ◽  
Kornel F. Ehmann

Complex three-dimensional miniature components are needed in a wide range of industrial applications from aerospace to biomedicine. Such products can be effectively produced by micro-end-milling processes that are capable of accurately producing high aspect ratio features and parts. This paper presents a mechanistic cutting force model for the precise prediction of the cutting forces in micro-end-milling under various cutting conditions. In order to account for the actual physical phenomena at the edge of the tool, the components of the cutting force vector are determined based on the newly introduced concept of the partial effective rake angle. The proposed model also uses instantaneous cutting force coefficients that are independent of the end-milling cutting conditions. These cutting force coefficients, determined from measured cutting forces, reflect the influence of the majority of cutting mechanisms involved in micro-end-milling including the minimum chip-thickness effect. The comparison of the predicted and measured cutting forces has shown that the proposed method provides very accurate results.


2005 ◽  
Vol 127 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Jeong Hoon Ko ◽  
Dong-Woo Cho

Application of a ball-end milling process model to a CAD/CAM or CAPP system requires a generalized methodology to determine the cutting force coefficients for different cutting conditions. In this paper, we propose a mechanistic cutting force model for 3D ball-end milling using instantaneous cutting force coefficients that are independent of the cutting conditions. The uncut chip thickness model for three-dimensional machining considers cutter deflection and runout. An in-depth analysis of the characteristics of these cutting force coefficients, which can be determined from only a few test cuts, is provided. For more accurate cutting force predictions, the size effect is also modeled using the cutter edge length of the ball-end mill and is incorporated into the cutting force model. This method of estimating the 3D ball-end milling force coefficients has been tested experimentally for various cutting conditions.


2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Yu Guo ◽  
Bin Lin ◽  
Weiqiang Wang

The paper presents a mechanistic cutting force model of serrated end mill to predict cutting forces. Geometric model of serrated end mill is established, which covers variable helix end mill geometries. In this model, the serration of helical cutting flutes is expressed spatially and the wave of serration is defined to be a sine wave. The spatial vector is applied to define chip thickness so as to enhance the spatial expressiveness of the model, which is perpendicular to the curvature of each flute. Each helical flute is scatted into a series of infinitesimal cutting edges. The infinitesimal cutting forces depend on three cutting force coefficients and three edge force coefficients in the tangential, radial, and axial directions at every cutting element. By integrating the infinitesimal cutting forces along each cutting edge, the milling forces with serrated end mill can be predicted. The model feasibility of the serrated end mill is verified by comparing the predicted and measured cutting forces. Moreover, the model is also verified such that it can also predict cutting forces with other types of end mills, such as variable helix serrated end mill, variable helix end mill, and regular end mill.


Author(s):  
Nhu-Tung Nguyen

This paper presents a modeling method of cutting force and a combination approach of theory and experimental methods in the determination of cutting force coefficients in the face milling process using a parallelogram insert. By the theoretical method, the cutting forces were modeled by a mathematical function of cutting cutter geometry (Cutter diameter, the number of inserts, the insert nose radius, insert cutting edge helix angle, etc.), cutting conditions (depth of cut, feed per flute, spindle speed, etc.), and cutting force coefficients (shear force coefficients, edge force coefficients). By the theoretical method, the average cutting forces in three directions (feed – x, normal – y, and axial – z) were modeled as the linear functions of feed per flute. By the experimental method, the average cutting forces in these three directions were also regressed as the linear functions of feed per flute with quite large determination coefficients (R2 were larger than 92 %). Then, the relationship of average cutting forces and feed per flute was used to determine all six cutting force coefficient components. The validation experiments were performed to verify the linear function of average cutting forces, to determine the cutting force coefficients, and to verify the cutting force models in the face milling process using a cutter with one parallelogram insert. The cutting force models were successfully verified by comparison of the shape and the values of predicted cutting forces and measured cutting forces. These proposed methods and models can be applied to determine the cutting force coefficients and predict the cutting force in the face milling process using a parallelogram insert and can be extended with other cutting types or other insert types


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