scholarly journals Prediction of Dynamic Milling Stability considering Time Variation of Deflection and Dynamic Characteristics in Thin-Walled Component Milling Process

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Li Zhang ◽  
Weiguo Gao ◽  
Dawei Zhang ◽  
Yanling Tian
Keyword(s):  
Computational Model ◽  
Dynamic Characteristic ◽  
Dynamic Characteristics ◽  
Time Variation ◽  
Material Removal ◽  
Manufacturing Industry ◽  
Experimental Testing ◽  
Milling Process ◽  
Milling Stability ◽  
Thin Walled

The milling stability of thin-walled component is an important problem in the aviation manufacturing industry. The milling stability is influenced by both deflection characteristic and dynamic characteristic of workpiece. Moreover, in the material removal, the deflection and dynamic characteristics of workpiece are time-variant on the change of machining positions. Thus, the milling stability is also time-variant. In order to investigate the time variation of deflection and dynamic characteristics of workpiece, a new computational model was established in this paper. Based on the influences of the deflection and the dynamic characteristics of workpiece, a new stability lobes diagram which can show different stability domains and chatter domains in different process positions was obtained. Experimental testing has been conducted to validate the established new model.

scholarly journals Position-Dependent Stability Prediction for Multi-Axis Milling of the Thin-Walled Component with a Curved Surface

2020 ◽  
Vol 10 (24) ◽  
pp. 8779
Author(s):  
Xiaojuan Wang ◽  
Qinghua Song ◽  
Zhanqiang Liu
Keyword(s):  
Material Removal ◽  
Variable Mass ◽  
Milling Process ◽  
Machining Process ◽  
Curved Surface ◽  
Structural Dynamic ◽  
Milling Stability ◽  
Integrated Method ◽  
Thin Walled ◽  
Cutting Path

Time-varying dynamic behaviors are essential to investigate the stability in the thin-walled workpiece milling process, which is usually affected by material removal and position-dependent characteristics of the workpiece along with the tool feed direction. To predict the milling stability with position-dependent, thin-walled component multi-axis milling, an improved structural dynamic modification method with variable mass is proposed in the paper. Firstly, the extraction of multi-axis milling material and the removal process of thin-walled parts with a complex curved surface and variable thickness is completed with CAM software. Then, the material removal of one cutting path as a modification of the structure is divided into multi-cutting steps with equal length to obtain the corrected FRFs in the machining process on the basis of the extended Sherman-Morrison-Woodbury formula. Furthermore, the dynamic characteristics of the initial un-machined workpiece and final machined workpiece are calculated by both experimental modal analysis and FEM. Finally, the multi-axis milling stability is predicted using the extended numerical integrated method, and an aero-engine blade is used to validate the accuracy and effectiveness of the proposed method for multi-axis milling molding parts.

scholarly journals Stability Research Considering Non-Linear Change in the Machining of Titanium Thin-Walled Parts

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2083 ◽  
Author(s):  
Haining Gao ◽  
Xianli Liu
Keyword(s):  
Titanium Alloy ◽  
Prediction Model ◽  
Dynamic Characteristics ◽  
Material Removal ◽  
Milling Process ◽  
Damping Coefficient ◽  
Linear Change ◽  
Process Damping ◽  
Thin Walled ◽  
The Stability

Aiming to solve the problem whereby the damping process effect is significant and difficult to measure during low-speed machining of titanium alloy thin-walled parts, the ploughing coefficient of the flank face is obtained based on the frequency-domain decomposition (FDD) of the measured vibration signal and the energy balance principle, and then the process-damping prediction model is obtained. Aiming to solve the problem of non-linear change of dynamic characteristics of a workpiece caused by the material removal effect in the machining of titanium alloy thin-walled parts, a prediction model of dynamic characteristics of a workpiece is established based on the structural dynamic modification method. Meanwhile, the effect of material removal on the process-damping coefficient is studied, and the internal relationship between the process-damping coefficient and the dynamic characteristics of the workpiece is revealed. The stability lobe diagram is obtained by the full discretization in the titanium alloy milling process. The correctness of the model and stability prediction is verified by experiments under different working conditions. It is found that the coupling characteristics of process-damping and workpiece dynamic characteristics control the stability of the milling process. The research results can provide theoretical support for accurate characterization and process optimization of titanium alloy thin-walled workpiece milling.

Modeling and Analysis Effects of Material Removal on Machining Dynamics in Milling of Thin-Walled Workpiece

2011 ◽  
Vol 223 ◽  
pp. 671-678 ◽  
Author(s):  
Ming Luo ◽  
Ding Hua Zhang ◽  
Bao Hai Wu ◽  
Ming Tang
Keyword(s):  
Material Removal ◽  
Dynamic Properties ◽  
Removal Rate ◽  
Milling Process ◽  
Machining Process ◽  
Machining Accuracy ◽  
Modeling And Analysis ◽  
Process System ◽  
Material Choice ◽  
Thin Walled

In aerospace industry, thin-walled workpieces are widely used in order to reduce the weight and to fulfill the high demands of their later applications. These workpieces are usually highly sophisticated and difficult to machine according to their geometry and material choice. In this paper, influence of material removal within the thin-walled workpiece machining operation on the dynamic properties of the workpiece and the machining process system is discussed. Aiming at learning about dynamic properties evolution during the machining operation, different milling processes of thin-walled plate are studied. Numerical simulation methods are employed in the study to investigate the dynamic properties evolution and machining stability with the material removal process in the milling process of thin-walled workpiece. The investigation results are expected to be used for designing optimized material removal sequence, which will guarantee highly material removal rate as well as highly machining accuracy of thin-walled workpiece.

Instantaneous Dynamics of Multi-Axis Milling Thin-Walled Workpiece with Complex Curved Surface

2016 ◽  
Vol 836-837 ◽  
pp. 529-535
Author(s):  
Gang Gang Ju ◽  
Qing Hua Song ◽  
Zhan Qiang Liu ◽  
Jia Hao Shi ◽  
Yi Wan ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Turbine Blades ◽  
Variable Mass ◽  
Milling Process ◽  
Cutting Process ◽  
Curved Surface ◽  
Structural Dynamic ◽  
Loading Effects ◽  
Thin Walled ◽  
Tool Position

The first step to predict the milling stability is to identify the dynamic characteristics of cutting process. And the mass loading effects of removal material play an important role on the dynamic characteristics of milling process for thin-walled parts, such as impeller, turbine blades and automobile components, which is changing with cutting time or tool position. Therefore, how to identify the instantaneous dynamic characteristics of milling process is one of the most significant problems. In the paper, a structural dynamic modification method with variable mass to predict the instantaneous dynamic characteristics of multi-axis milling thin-walled workpiece with complex curved surface is proposed. The proposed method takes into account the variations of dynamics characteristics of workpiece with the tool position and material removal. And the material cutting process is regarded as the structural dynamic modifications of cutting system, the instantaneous dynamic characteristics of which can be estimated by the extended Sherman-Morrison-Woodbury formula to obtain the corrected frequency response function (FRF). Experiments were carried out to obtain the instantaneous dynamics of a thin-walled workpiece and the results were verified by finite element method (FEM).

Research on Chatter Suppression in Machining Thin-Walled Components Based on Rigidity Optimization

2010 ◽  
Vol 97-101 ◽  
pp. 1947-1951 ◽  
Author(s):  
Jun Xue Ren ◽  
Bi Qi Yang ◽  
Yong Shou Liang ◽  
Wei Jun Tian ◽  
Chang Feng Yao
Keyword(s):  
Cutting Force ◽  
Material Removal ◽  
Milling Process ◽  
Precision Machining ◽  
Chatter Vibration ◽  
Sequence Optimization ◽  
Chatter Suppression ◽  
Stiffness Optimization ◽  
Machining Errors ◽  
Thin Walled

Precision machining of thin-walled complex components has been a serious challenge, and the machining errors are mainly due to cutting force which can induce tool-workpiece deformation and chatter vibration phenomenon. Based on the principle of stiffness optimization and material removal sequence optimization, rigidity of thin-walled component is greatly improved with non-uniform allowance distribution and spiral milling process techniques.

On-Site Experimental Testing to Study the Vibration of Composite Floors

2014 ◽  
Vol 601 ◽  
pp. 231-234
Author(s):  
Cristian Lucian Ghindea ◽  
Dan Cretu ◽  
Monica Popescu ◽  
Radu Cruciat ◽  
Elena Tulei
Keyword(s):  
Dynamic Characteristics ◽  
Experimental Testing ◽  
Concrete Slab ◽  
Human Perception ◽  
Experimental Tests ◽  
International Standards ◽  
Structural Element ◽  
Element Analysis ◽  
Floor Slabs ◽  
Composite Floors

As a general trend, in order to reduce material consumption or to reduce the mass of the structures, composite floor slabs solutions are used to achieve large spans floor slabs. This solutions led to floors sensitive to vibrations induced generally by human activities. As a verification of the design concepts of the composite floors, usually, it is recommended a further examination of the floor after completion by experimental tests. Although the experimental values of the dynamic response of the floor are uniquely determined, the processing can take two directions of evaluation. The first direction consist in determining the dynamic characteristics of the floor and their comparison with the design values. Another way that can be followed in the processing of the experimental results is to consider the human perception and comfort to the vibration on floors. The paper aims to present a case study on a composite floor, with steel beams and concrete slab, tested on-site. Both aspects of data processing are analyzed, in terms of the structural element, and in terms of the effect on human perception and comfort. Experimentally obtained values for the dynamic characteristics of the floor are compared with numerical values from finite element analysis, while the second type of characteristic values are compared with various human comfort threshold values found in international standards.

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