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.

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.

Mechanism of Variable Helix Tools in Suppressing Chatter Using Process Damping for Machining Titanium Alloys at Low Cutting Speed

2013 ◽  
Vol 773-774 ◽  
pp. 370-376
Author(s):  
Muhammad Adib Shaharun ◽  
Ahmad Razlan Yusoff ◽  
Mohammad S. Reza
Keyword(s):  
Titanium Alloy ◽  
Cutting Speed ◽  
Milling Process ◽  
Cutting Process ◽  
Chatter Vibration ◽  
Process Damping ◽  
High Cutting Speed ◽  
Titanium Machining ◽  
Different Types ◽  
Variable Helix

Titanium is difficult-to-cut materials due to its poor machinability and thermal conductivity when machining at high cutting speed. To overcome this machining titanium alloy problem, this study in interaction between machining structural system and the cutting process are very important. One of the main problems in the cutting process is chatter vibration. Due to chatter problem, the mechanism to suppress chatter named, process damping is a useful method can be manipulated to improve the limited productivity of titanium machining at low speed machining in milling process. In the present study, experiment are conducted to evaluate and study the process damping mechanism in milling using different types of variable tools geometries. These tools are variable he-lix/uniform pitch, variable pitch/uniform helix and variable helix and pitch and uniform helix/pitch. The result showed that the variable helix and pitch tools is very significantly improve process damping performance in machining titanium alloy compare to traditional of regular tools and other irregular tools.

Analytical Prediction and Experimental Investigation of Burnishing Force in Rotary Ultrasonic Roller Burnishing Titanium Alloy Ti–6Al–4V

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Jian Zhao ◽  
Zhanqiang Liu ◽  
Bing Wang ◽  
Yukui Cai ◽  
Qinghua Song
Keyword(s):  
Titanium Alloy ◽  
Prediction Model ◽  
Milling Process ◽  
Analytical Prediction ◽  
Ultrasonic Power ◽  
Machined Surface ◽  
Softening Effect ◽  
Force Prediction ◽  
Contact Width ◽  
Acoustic Softening

Abstract Ultrasonic burnishing is usually applied to make machined surface modification. The acoustic softening effect caused by ultrasonic vibration is beneficial to the machining of difficult-to-cut materials. In the present work, a burnishing force prediction model was proposed for rotary ultrasonic burnishing of titanium alloy Ti–6Al–4V, whose surface had been machined with the face milling process. Firstly, the contact between the burnishing roller and one single milling mark was analyzed with plane strain assumption based on the Boussinesq–Flamant contact problem. Then, the effect of ultrasonic softening on the yield stress of Ti–6Al–4V was investigated. The critical contact width and contact load that the burnishing roller crushed on one single milling mark were examined to confirm the feasibility of the proposed ultrasonic burnishing force prediction model. The experimental verifications were carried out at various ultrasonic powers. The burnishing forces from experiment measurements were consistent with the calculated results from the proposed model. The mean deviations between theoretical and experimental results of the ultrasonic burnishing force were 10.4%, 12.2%, and 15.2%, corresponding to the ultrasonic power at the level of 41 W, 158 W, and 354 W, respectively.

scholarly journals Modeling and Application of Process Damping in Milling of Thin-Walled Workpiece Made of Titanium Alloy

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xin Li ◽  
Wei Zhao ◽  
Liang Li ◽  
Ning He ◽  
ShengWei Chi
Keyword(s):  
Titanium Alloy ◽  
Aviation Industry ◽  
Structural Stiffness ◽  
Nonlinear Dynamic Model ◽  
Machined Surface ◽  
Machine Material ◽  
Process Damping ◽  
Clearance Angle ◽  
Flank Face ◽  
Thin Walled

The modeling as well as application of process damping in milling of thin-walled workpiece made of titanium alloy is investigated. Titanium alloy used commonly in aviation industry is one typical difficult-to-machine material. Chatter usually occurs in cutting of titanium alloy, which results in poor surface quality and damaged tool. Thus, chatter is one important restriction for the quality and efficiency of titanium alloy manufacture, especially for the thin-walled workpiece made of titanium alloy due to poor structural stiffness. Process damping results from interference between flank face and machined surface, which is critical but usually ignored in chatter analysis for difficult-to-machine material. The paper presents one nonlinear dynamic model considering process damping for milling of thin-walled workpiece made of titanium alloy and designs antivibration clearance angle to suppress chatter based on the model. The experimental and computational results indicate that the presented methods for chatter stability analysis are reasonable, and the antivibration clearance angle designed is effective in suppressing chatter and improving machining quality.

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.

Analysis on the Effect of System Parameter on Double Cantilevers Vibro-Impact System Response

2012 ◽  
Vol 518-523 ◽  
pp. 3878-3886 ◽  
Author(s):  
Yu Rong Wang ◽  
Tian Xing Wu
Keyword(s):  
Dynamic Characteristics ◽  
Milling Process ◽  
System Response ◽  
Nonlinear Phenomena ◽  
Important Research ◽  
Instability Mechanism ◽  
System Parameters ◽  
Impact System ◽  
Practical Engineering ◽  
The Stability

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.

Stability Prediction of Milling Process With Closed Machining System Dynamics With Flexible Thin-Walled Workpiece

2015 ◽  
Author(s):  
Chao Xu ◽  
Pingfa Feng ◽  
Dingwen Yu ◽  
Zhijun Wu ◽  
Jianfu Zhang
Keyword(s):  
Support System ◽  
Milling Process ◽  
Machining Process ◽  
Stability Lobe Diagram ◽  
Closed Model ◽  
Flexible Support ◽  
Stability Lobe ◽  
Machining System ◽  
Thin Walled ◽  
The Stability

Despite recent advances and improvements in modeling and prediction of the dynamics of the machining process, an efficient machining process is limited due to chatter and instability of machining system. In fact, the machining system contains various kinds of joints, which cause difficulties in dynamics modeling, simulation and prediction. Moreover, the flexible support system results in large deformation and violent vibration of the workpiece when machining, and the thin-walled workpiece easily gives rise to the chatter of the machining system. Therefore, the dynamics of the flexible support system was considered to calculate stability lobe diagram in the modeling of milling process. The whole machining system was regarded as a closed loop composed by the machine tool structures, support, workpiece and machining process. In this paper, the receptance coupling (RC) method was introduced to predict the dynamics of the closed machining system. A milling process was taken for example to predict the chatter limitations using the dynamics of closed model. The mathematical model of the machining system (machine tool structures, spindle, holder and tool), together with the details of joint contacts, was given based on the RC method. The RC model was used to obtain the dynamics of the system, while receptance of the tool point was coupled. Based on the coupling model of the machining system, the depth limitations under different speeds were estimated for the technology parameter optimization in milling process. The response was considered to be the sum of the cutting point and the support system. The flexibility of the support system was considered to be the feedback of the cutting stiffness. By this means, the traditional model was modified to calculate the stability lobe diagram based on the dynamics of the spindle and support system. Furthermore, the milling experiment was carried out to verify the prediction results, and the dominant natural frequencies of receptance at tool point were obtained by modal testing to define the stability lobe diagram. It was found that the chatter results matched well with the stability lobes. It was concluded that the support system with poor stiffness might cause violent chatter especially when the workpiece was thin-walled. The cutting depth limitations of the flexible support system were lower than that of the rigid one. Moreover, this closed model of the machining system is appropriate for the chatter prediction of the flexible support system or thin-walled workpiece, so it is helpful for a better parameter optimization.

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.

Influence of Cutter Geometric Parameters on the Stability of Milling Process of Thin-Walled Blades

2012 ◽  
Vol 443-444 ◽  
pp. 21-26 ◽  
Author(s):  
Wei Wei Liu ◽  
Xiao Juan Gao ◽  
Chen Wei Shan ◽  
Wei Jun Tian
Keyword(s):  
High Performance ◽  
Cutting Parameters ◽  
Milling Process ◽  
Chatter Vibration ◽  
Clamping System ◽  
Cutting Deformation ◽  
Thin Walled ◽  
Simulation Results ◽  
The Stability ◽  
New System

In this paper, a new experiment procedure is proposed to study the influence of cutter parameters and clamping methods on the stability of the milling process of thin-walled blade. A dedicated fixture is designed to carry out the experiment. Simulation results show that the new clamping system can enhance the rigidity of thin-walled blade to reduce cutting deformation and chatter vibration phenomenon. Then, cutter and cutting parameters can be optimized properly to make the system obtain high rigidity and high performance stable milling process. Industrial application indicates that the new system can improve the cutting performance and ensure the cutting quality.

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