Gaussian approach–based cutting force coefficient identification for flat-end milling operation

Abstract In aviation and navigation, complicated parts are milled with high-speed low-feed-per-tooth milling to decrease tool vibration for high quality. Because the nonlinearity of the cutting force coefficient (CFC) is more evident with the relatively smaller instantaneous uncut chip thickness, the stable critical cutting depth and its distribution against different tool postures are affected. Considering the nonlinearity, a nonlinear dynamic CFC model that reveals the effect of the dynamic instantaneous uncut chip thickness on the dynamic cutting force is derived based on the Taylor expansion. A five-axis bull-nose end milling dynamics model is established with the nonlinear dynamic CFC model. The stable critical cutting depth distribution with respect to tool posture is analyzed. The stability results predicted with the dynamic CFC model are compared with those from the static CFC model and the constant CFC model. The effects of tool posture and feed per tooth on stable critical cutting depth were also analyzed, and the proposed model was validated by cutting experiments. The maximal stable critical cutting depths that can be achieved under different tool postures by feed per tooth adjustment were calculated, and corresponding distribution diagrams are proposed for milling parameter optimization.

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FRACTAL-BASED ANALYSIS OF THE VARIATIONS OF CUTTING FORCES ALONG DIFFERENT AXES IN END MILLING OPERATION

Fractals ◽

10.1142/s0218348x18500895 ◽

2018 ◽

Vol 26 (06) ◽

pp. 1850089 ◽

Cited By ~ 19

Author(s):

HAMIDREZA NAMAZI ◽

ALI AKHAVAN FARID ◽

TECK SENG CHANG

Keyword(s):

Fractal Dimension ◽

Cutting Force ◽

Cutting Forces ◽

End Milling ◽

Fractal Theory ◽

Radial Force ◽

Machining Conditions ◽

Feed Force ◽

Milling Operation ◽

Force Signal

Analysis of cutting forces in machining operation is an important issue. The cutting force changes randomly in milling operation where it makes a signal by plotting over time span. An important type of analysis belongs to the study of how cutting forces change along different axes. Since cutting force has fractal characteristics, in this paper for the first time we analyze the variations of complexity of cutting force signal along different axes using fractal theory. For this purpose, we consider two cutting depths and do milling operation in dry and wet machining conditions. The obtained cutting force time series was analyzed by computing the fractal dimension. The result showed that in both wet and dry machining conditions, the feed force (along [Formula: see text]-axis) has greater fractal dimension than radial force (along [Formula: see text]-axis). In addition, the radial force (along [Formula: see text]-axis) has greater fractal dimension than thrust force (along [Formula: see text]-axis). The method of analysis that was used in this research can be applied to other machining operations to study the variations of fractal structure of cutting force signal along different axes.

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Prediction of Nonlinear Micro-Milling Force with a Novel Minimum Uncut Chip Thickness Model

Micromachines ◽

10.3390/mi12121495 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1495

Author(s):

Tongshun Liu ◽

Kedong Zhang ◽

Gang Wang ◽

Chengdong Wang

Keyword(s):

Cutting Force ◽

Chip Thickness ◽

Micro Milling ◽

Force Model ◽

Force Coefficient ◽

Uncut Chip Thickness ◽

Milling Force ◽

Minimum Uncut Chip Thickness ◽

Cutting Force Coefficient ◽

Milling Force Model

The minimum uncut chip thickness (MUCT), dividing the cutting zone into the shear region and the ploughing region, has a strong nonlinear effect on the cutting force of micro-milling. Determining the MUCT value is fundamental in order to predict the micro-milling force. In this study, based on the assumption that the normal shear force and the normal ploughing force are equivalent at the MUCT point, a novel analytical MUCT model considering the comprehensive effect of shear stress, friction angle, ploughing coefficient and cutting-edge radius is constructed to determine the MUCT. Nonlinear piecewise cutting force coefficient functions with the novel MUCT as the break point are constructed to represent the distribution of the shear/ploughing force under the effect of the minimum uncut chip thickness. By integrating the cutting force coefficient function, the nonlinear micro-milling force is predicted. Theoretical analysis shows that the nonlinear cutting force coefficient function embedded with the novel MUCT is absolutely integrable, making the micro-milling force model more stable and accurate than the conventional models. Moreover, by considering different factors in the MUCT model, the proposed micro-milling force model is more flexible than the traditional models. Micro-milling experiments under different cutting conditions have verified the efficiency and improvement of the proposed micro-milling force model.

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Identification of static surface form errors from cutting force distribution in flat-end milling processes

Journal of the Brazilian Society of Mechanical Sciences and Engineering ◽

10.1007/s40430-014-0224-1 ◽

2014 ◽

Vol 37 (3) ◽

pp. 1001-1013 ◽

Cited By ~ 10

Author(s):

Mehmet Aydın ◽

Mehmet Uçar ◽

Abdulkadir Cengiz ◽

Mustafa Kurt

Keyword(s):

Cutting Force ◽

End Milling ◽

Force Distribution ◽

Surface Form ◽

Form Errors ◽

Flat End Milling

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Analytical Prediction of Stability Lobes in Ball End Milling

Journal of Manufacturing Science and Engineering ◽

10.1115/1.2833064 ◽

1999 ◽

Vol 121 (4) ◽

pp. 586-592 ◽

Cited By ~ 85

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.

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