A Model-Based Computationally Efficient Method for On-Line Detection of Chatter in Milling

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Lei Ma ◽  
Shreyes N. Melkote ◽  
James B. Castle
Keyword(s):  
Cutting Force ◽  
Efficient Method ◽  
Frequency Estimation ◽  
Chip Thickness ◽  
Computationally Efficient ◽  
Model Based ◽  
Chatter Suppression ◽  
Force Signal ◽  
Regeneration Effect ◽  
Milling Chatter

This paper presents a model-based computationally efficient method for detecting milling chatter in its incipient stages and for chatter frequency estimation by monitoring the cutting force signals. Based on a complex exponentials model for the dynamic chip thickness, the chip regeneration effect is amplified and isolated from the cutting force signal for early chatter detection. The proposed method is independent of the cutting conditions. With the aid of a one tap adaptive filter, the method is shown to be capable of distinguishing between chatter and the dynamic transients in the cutting forces arising from sudden changes in workpiece geometry and tool entry/exit. To facilitate chatter suppression once the onset of chatter is detected, a time domain algorithm is proposed so that the dominant chatter frequency can be accurately determined without using computationally expensive frequency domain transforms such as the Fourier transform. The proposed method is experimentally validated.

A Model Based Computationally Efficient Method for On-Line Detection of Chatter in Milling

2013 ◽  
Author(s):  
Lei Ma ◽  
Shreyes Melkote ◽  
James Castle
Keyword(s):  
Efficient Method ◽  
Chip Thickness ◽  
Line Detection ◽  
Chatter Detection ◽  
Computationally Efficient ◽  
Model Based ◽  
Force Signal ◽  
On Line ◽  
Regeneration Effect ◽  
Milling Chatter

This paper presents a model-based computationally efficient method for detecting milling chatter in its incipient stages. Based on a complex exponentials model for the dynamic chip thickness, the chip regeneration effect is amplified and isolated from the cutting force signal for early chatter detection. The proposed method is independent of the cutting conditions. With the aid of a one tap adaptive filter, the proposed method is also found to be able to distinguish between chatter and the dynamic transients in the cutting forces due to sudden changes in workpiece geometry and tool entry/exit. The proposed method is experimentally validated.

scholarly journals An Open Modular Architecture Controller Based Online Chatter Suppression System for CNC Milling

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Zhenyu Han ◽  
Hongyu Jin ◽  
Maoyue Li ◽  
Hongya Fu
Keyword(s):  
Cutting Parameters ◽  
Cnc Milling ◽  
Modular Architecture ◽  
Part Quality ◽  
Chatter Suppression ◽  
Command Generation ◽  
Force Signal ◽  
Milling Chatter ◽  
The Relationship ◽  
Acceleration Signals

In milling processes, chatter is a kind of sudden relative vibration appearing between the cutter and the workpiece, which results in poor part quality, accelerated tool wear, and shortened spindle life. In this paper, an open modular architecture controller (OMAC) of machine tool which integrates the algorithms including chatter recognition, compensation command generation, and execution is proposed with the aim of providing an integrated solution for milling chatter suppression in CNC kernel. To effectively identify chatter, experiments are designed to determine the optimal installation place of accelerometer and then triaxial cutting forces and acceleration signals are compared to see which are more sensitive to chatter onset. In terms of data processing, 16 sampling points in time domain are chosen to perform online fast Fourier transform (FFT) in consideration of signal effectiveness and computational efficiency. To implement real-time chatter suppression in CNC kernel, a simplified dynamic model of milling system is used to obtain the relationship between chatter frequency and spindle speed. Finally, an adaptive control module which completes force signal extraction and processing by FFT and has the ability to modify related cutting parameters is designed to interact with other modules in OMAC where data acquisition thread and interpolation thread are synchronized. The proposed system is experimentally validated.

scholarly journals Generalized cutting force model for peripheral milling of wood, based on the effect of density, uncut chip cross section, grain orientation and tool helix angle

2021 ◽  
Author(s):  
R. Curti ◽  
B. Marcon ◽  
L. Denaud ◽  
M. Togni ◽  
R. Furferi ◽  
...  
Keyword(s):  
Cutting Force ◽  
Chip Thickness ◽  
Helix Angle ◽  
Force Model ◽  
Cutting Force Model ◽  
Peripheral Milling ◽  
Grain Angle ◽  
Model Based ◽  
Cutting Coefficients ◽  
Machining Operations

AbstractThe influence of the grain angle on the cutting force when milling wood is not yet detailed, apart from particular cases (end-grain, parallel to the grain, or in some rare cases 45°-cut). Thus, setting-up wood machining operations with complex paths still relies mainly on the experience of the operators because of the lack of scientific knowledge easily transferable to the industry. The aim of the present work is to propose an empirical model based on specific cutting coefficients for the assessment of cutting force when peripheral milling of wood based on the following input: uncut chip thickness and width, grain angle (angle between the tool velocity vector and the grain direction of the wood), density and tool helix angle. The specific cutting coefficients were determined by peripheral milling with different depths of cut wood disks issued from different wood species on a dynamometric platform to record the forces. Milling a sample into a round shape (a disk) allows to measure the cutting forces toward every grain angle into a sole basic diameter reduction operation. Force signals are then post-processed to carefully clean the natural vibrations of the system without impacting their magnitudes. The experiment is repeated on five species with a large range of densities, machining two disks per species for five depths of cut in up- and down milling conditions for three different tool helix angles. Finally, a simple cutting force model, based on the previously cited parameters, is proposed, and its robustness analysed.

scholarly journals An Effective Potential for Frenkel Excitons

2020 ◽  
Author(s):  
Bartosz Błasiak ◽  
Wojciech Bartkowiak ◽  
Robert Władysław Góra
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Efficient Method ◽  
Effective Potential ◽  
Excitation Energy Transfer ◽  
Computationally Efficient ◽  
Frenkel Excitons

Excitation energy transfer (EET) is a ubiquitous process in life and materials sciences. Here, a new and computationally efficient method of evaluating the electronic EET couplings between interacting chromophores is...

scholarly journals Correction and accuracy improvement of non-parallel shear zone model

2018 ◽  
Vol 207 ◽  
pp. 02002
Author(s):  
Yaoke Wang ◽  
Meng Kou ◽  
Wei Ding ◽  
Huan Ma ◽  
Liangshan Xiong
Keyword(s):  
Experimental Data ◽  
Cutting Force ◽  
Shear Zone ◽  
Coordinate Transformation ◽  
Chip Thickness ◽  
Zone Model ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
Experimental Values ◽  
1045 Steel

When applying the non-parallel shear zone model to predict the cutting process parameters of carbon steel workpiece, it is found that there is a big error between the prediction results and the experimental values. And also, the former approach to obtain the relevant cutting parameters of the non-parallel shear zone model by applying coordinate transformation to the parallel shear zone model has a theoretical error – it erroneously regards the determinant (|J|) of the Jacobian matrix (J) in the coordinate transformation as a constant. The shape of the shear zone obtained when |J| is not constant is drew and it is found that the two boundaries of the shear zone are two slightly curved surfaces rather than two inclined planes. Also, the error between predicted values and experimental values of cutting force and cutting thrust is slightly smaller than that of constant |J|. A corrected model where |J| is a variable is proposed. Since the specific values of inclination of the shear zone (α, β), the thickness coefficient of the shear zone (as) and the constants related to the material (f0, p) are not given in the former work, a method to obtain the above-mentioned five constants by solving multivariable constrained optimization problem based on experimental data was also proposed; based on the obtained experimental data of AISI 1045 steel workpiece cutting force, cutting thrust, chip thickness, the results of five above-mentioned model constants are obtained. It is found that, compared with prediction from uncorrected model, the cutting force and cutting thrust of AISI 1045 steel predicted by the corrected model with the obtained constants has a better agreement with the experimental values obtained by Ivester.

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