Identification of Machining System Dynamics by Equation Error Minimization

1978 ◽  
Vol 100 (3) ◽  
pp. 332-339 ◽  
Author(s):  
K. Srinivasan ◽  
C. L. Nachtigal
Keyword(s):  
System Dynamics ◽  
Cutting Force ◽  
Analog Computer ◽  
System Response ◽  
Error Minimization ◽  
Minimization Method ◽  
Identification Method ◽  
Dynamic Cutting Force ◽  
Equation Error ◽  
Machining System

The application of a sequential equation error minimization method to the identification of the dynamics of machining systems is described here. The development of the identification method was motivated by the need for models of machining system dynamics for the design of active chatter controllers. The dynamic cutting force parameters as well as the machine structure transfer function parameters are required for this task. This identification method is novel in the machine tool area in that it identifies both cutting force parameters and structure parameters with the same experimental data. A convenient excitation of the system dynamics is chosen. The system response is prefiltered before being processed and the equation error minimization scheme is refined to insure the validity of the results obtained. The correctness of the identification scheme is verified by using it to identify parameters in analog computer simulations of practical maching systems. The results of structural identification for experimental plunge cutting operations are also presented here.

Modeling of residual stresses by correlating surface topography in machining of AISI 52100 steel

2021 ◽  
pp. 1-26
Author(s):  
Chao Liu ◽  
Yan He ◽  
Yufeng Li ◽  
Yulin Wang ◽  
Shilong Wang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Cutting Force ◽  
Surface Topography ◽  
Analytical Model ◽  
Analytical Models ◽  
Workpiece Surface ◽  
Dynamic Cutting Force ◽  
Intermittent Cutting ◽  
Effect Of Surface

Abstract The residual stresses could affect the ability of components to bear loading conditions and also the performance. The researchers considered workpiece surface as a plane and ignored the effect of surface topography induced by the intermittent cutting process when modeling residual stresses. The aim of this research develops an analytical model to predict workpiece residual stresses during intermittent machining by correlating the effect of surface topography. The relative motions of tool and workpiece are analyzed for modeling thermal-mechanical and surface topography. The influence of dynamic cutting force and thermal on different positions of surface topography is also considered in analytical model. Then the residual stresses model with the surface topography effect can be developed in intermittent cutting. The analytical models of dynamic cutting force, surface topography and residual stresses are verified by the experiments. The variation trend of evaluated values of the residual stress of workpiece is basically consistent with that of measured values. The compressive residual stress of workpiece surface in highest point of the surface topography are higher than that in the lowest point.

Analysis of the effect of tool posture on stability considering the nonlinear dynamic cutting force coefficient

2021 ◽  
pp. 1-19
Author(s):  
Zepeng Li ◽  
Rong Yan ◽  
Xiaowei Tang ◽  
Fang Yu Peng ◽  
Shihao Xin ◽  
...  
Keyword(s):  
Cutting Force ◽  
Nonlinear Dynamic ◽  
Chip Thickness ◽  
Cutting Depth ◽  
Force Coefficient ◽  
Critical Cutting Depth ◽  
Dynamic Cutting Force ◽  
Cutting Force Coefficient ◽  
Tool Posture ◽  
Instantaneous Uncut Chip Thickness

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.

A New Approach to the Early Prediction of Turning Chatter

1994 ◽  
Vol 116 (4) ◽  
pp. 485-488 ◽  
Author(s):  
Shan-Fei Bao ◽  
Wen-Guo Zhang ◽  
Jun-Yi Yu ◽  
Si-Mao Qiao ◽  
Fu-Lun Yang
Keyword(s):  
Theoretical Analysis ◽  
Cutting Force ◽  
Frequency Difference ◽  
Early Prediction ◽  
New Approach ◽  
Dynamic Cutting Force

A new approach to the early prediction of turning chatter is described in this paper; the interval frequency difference H in the amplitude domain of the dynamic cutting force is taken as a prediction parameter. The theoretical analysis and experiments results indicate that the approach presented can lead to a quick prediction of turning chatter with higher accuracy and adaptability.

Improved dynamic cutting force modelling in micro milling of metal matrix composites part II: Experimental validation and prediction

2019 ◽  
Vol 234 (8) ◽  
pp. 1500-1515
Author(s):  
Zhichao Niu ◽  
Kai Cheng
Keyword(s):  
Cutting Force ◽  
Metal Matrix Composites ◽  
Cutting Forces ◽  
Metal Matrix ◽  
Micro Milling ◽  
Force Model ◽  
Matrix Composites ◽  
Cutting Force Model ◽  
Side Milling ◽  
Dynamic Cutting Force

The effects of cutting dynamics and the particles' size and density cannot be ignored in micro milling of metal matrix composites. This article presents the improved dynamic cutting force modelling for micro milling of metal matrix composites based on the previous analytical model. This comprehensive improved cutting force model, taking the influence of the tool run-out, actual chip thickness and resultant tool tip trajectory into account, is evaluated and validated through well-designed machining trials. A series of side milling experiments using straight flutes polycrystalline diamond end mills are carried out on the metal matrix composite workpiece under various cutting conditions. Subsequently, the measured cutting forces are compensated by a Kalman filter to achieve the accurate cutting forces. These are further compared with the predicted cutting forces to validate the proposed dynamic cutting force model. The experimental results indicate that the predicted and measured cutting forces in micro milling of metal matrix composites are in good agreement.

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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