Dynamic characteristics of “tool-workpiece” elastic system in the low stiffness parts milling process

2021 ◽  
pp. 225-236
Author(s):  
Y. Danylchenko ◽  
A. Petryshyn ◽  
S. Repinskyi ◽  
V. Bandura ◽  
M. Kalimoldayev ◽  
...  
2013 ◽  
Vol 820 ◽  
pp. 67-70
Author(s):  
Tuo Li ◽  
Hong Bai Bai ◽  
Chun Hong Lu

Knitted-dapped metal rubber was developed to solve problems of metal rubber with low stiffness and test samples with different sizes were manufactured. Static tests and dynamic tests were carried out to study influences of density and thickness on the static stiffness and influences of frequency, amplitude and preload on dynamic characteristics. Results show that static stiffness rises when density or thickness increases. Frequency has little influence on dynamic characteristics. Knitted-dapped metal rubber will have smaller stiffness and better characteristics of damping, if amplitude increases; if preload increases, energy consumed in the vibration will be more.


2012 ◽  
Vol 723 ◽  
pp. 124-129
Author(s):  
Zhi Gang Liu ◽  
Hou Jun Qi ◽  
Yu Jun Cai

The thin-walled blade of aero engine has low stiffness, during machining, it easily generates deflection due to the milling force, but because high accuracy of such component is required, the prediction of the deflection exactly becomes extremely important. Therefore, this paper analyzes the milling process, and simplifies it reasonably. The deformation of the blade is predicted based on ABAQUS using FEM, and then the machining deflection curves of the blade is got. The result is analyzed soon afterwards, and deflection law is summarized. Finally, an experiment has been designed. The reliability of the method of predicting deflection is proved by comparing the measurement results and the simulation ones.


2012 ◽  
Vol 518-523 ◽  
pp. 3878-3886 ◽  
Author(s):  
Yu Rong Wang ◽  
Tian Xing Wu

The dynamic response of double cantilever vibro-impact system such as the stability of periodic motion, bifurcation etc., is an extremely important research content. However, the system dynamic characteristics are often influenced by the system parameters. Therefore, the theoretical modal of a double cantilevers vibro-impact system was established in this work, and the influence of clearance, damping and cubic nonlinear item on the dynamic characteristics of double cantilever vibro-impact system is detailedly analyzed through the numerical method .The results is helpful to analyze the practical engineering and to explore the nonlinear phenomena and the instability mechanism of the vibro-impact system such as milling process.


2005 ◽  
Vol 128 (1) ◽  
pp. 194-203 ◽  
Author(s):  
Sang Won Lee ◽  
Rhett Mayor ◽  
Jun Ni

Miniaturized machine tools, referred to as mesoscale machine tools (mMTs) henceforth, have been proposed as a way to manufacture micro/mesoscale mechanical components. A thorough study of the dynamic behavior of the mMT is required for the successful development of its machine structure. This paper demonstrates the development of an mMT, the performance evaluation of its mesoscale milling process, and the characterization of its dynamic behavior. The mMT is developed by using an air turbine spindle and three piezoelectric linear stages, and its volumetric size is 150×70×140mm. A series of micro/mesoscale milling experiments are conducted, and the performances in the developed mMT testbed are evaluated. The dynamic characteristics of the mMT can be different from those of conventional machine tools because the mMT is a miniaturized structure and comprises different machine components. Therefore, the effect of the miniaturization of a structure on the change of its dynamic behavior, called scaling law of the structural dynamics, is studied numerically and experimentally. The dynamic characteristics of the developed mMT that are estimated from the scaling law of the structural dynamics are much different from those obtained from an experimental modal analysis, and the flexible joints of the developed mMT are mainly responsible for this significant difference. Therefore, the joint dynamics of the mMT are studied by introducing an equivalent lumped parameter model, thus enabling simple identification of the joint dynamics and the effective modification of its critical joints to enhance a machining performance.


2016 ◽  
Vol 836-837 ◽  
pp. 529-535
Author(s):  
Gang Gang Ju ◽  
Qing Hua Song ◽  
Zhan Qiang Liu ◽  
Jia Hao Shi ◽  
Yi Wan ◽  
...  

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).


Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2083 ◽  
Author(s):  
Haining Gao ◽  
Xianli Liu

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.


2017 ◽  
Vol 107 (01-02) ◽  
pp. 39-44
Author(s):  
O. Kuklevskyi ◽  
S. Weiland ◽  
T. Stehle

Bei der Fräsbearbeitung mit Industrierobotern sowie anderen Sonderkinematiken werden aufgrund der niedrigen Steifigkeit die Fertigungsgenauigkeit und die Produktivität durch prozessinduzierte Schwingungen und Vibrationen eingeschränkt. Es werden in diesem Fachartikel verschiedene grundlegende Möglichkeiten diskutiert, wie sich die Genauigkeit beim Fräsen erhöhen lässt. Anschließend werden einige mögliche Konzepte zur Erzeugung von inertial-dynamischen Kräften zum Zerspankraftausgleich vorgeschlagen.   Due to vibrations induced by the milling process industrial robots and other guiding kinematics with low stiffness suffer of reduced productivity and machining accuracy. In the following paper we will discuss various alternatives to improve milling accuracy. Subsequently we will propose several concepts for cutting force compensation using inertial-dynamic forces.


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