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.

Effect of Drilling Parameters on Hole Quality of Ti-6Al-4V Titanium Alloy in Dry Drilling

2016 ◽  
Vol 880 ◽  
pp. 33-36 ◽  
Author(s):  
Saad Waqar ◽  
Saad Asad ◽  
Shamraiz Ahmad ◽  
Ch Asad Abbas ◽  
Hassan Elahi
Keyword(s):  
Titanium Alloy ◽  
Drill Hole ◽  
Hole Quality ◽  
Machined Surface ◽  
Machine Material ◽  
Dry Drilling ◽  
Drilling Parameters ◽  
Machining Operations ◽  
Exit Burr

In past few decades, a lot of research has been done in the field of machining to improve the quality of machined surface. Out of these machining operations, drilling is widely used in the areas of marine and aerospace for assembly requirements. Titanium alloy Ti-6Al-4V, owing to its vast applications, is regarded as an important material for these industries. Ti-6Al-4V is categorized as difficult to machine material. Based on above stated facts, an experimental study was conducted on the dry drilling of Ti-6Al-4V. The objective of this study was to establish the correlations between drilling parameters such as feed rate and spindle speed, and quality of machined surface which is evaluated in terms of drill hole diameter deviation, exit burr height and surface roughness.

scholarly journals Implementation of high speed machining in thin-walled aircraft integral elements

2018 ◽  
Vol 8 (1) ◽  
pp. 162-169 ◽  
Author(s):  
Paweł Bałon ◽  
Edward Rejman ◽  
Robert Smusz ◽  
Janusz Szostak ◽  
Bartłomiej Kiełbasa
Keyword(s):  
High Speed ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Raw Material ◽  
Aviation Industry ◽  
Machining Time ◽  
Machined Surface ◽  
Thin Walled ◽  
The Difference ◽  
Complex Integral

Abstract High speed milling (HSM) is currently one of the most important technologies used in the aviation industry, especially concerning aluminium alloys. The difference between HSM and other milling techniques is the ability to select cutting parameters – depth of the cut layer, feed rate, and cutting speed, in order to simultaneously ensure high quality, precision of the machined surface, and high machining efficiency, all of which shorten the manufacturing process of the integral components. By implementing the HSM technology, it is possible to manufacture very complex integral thin-walled aerial parts from the full quantity of the raw material. At present, aircraft structures are designed to mainly consist of integral elements which have been produced by welding or riveting of component parts in technologies utilized earlier in the production process. Parts such as ribs, longitudinals, girders, frames, coverages of fuselage and wings can all be categorized as integral elements. These parts are assembled into larger assemblies after milling. The main aim of the utilized treatments, besides ensuring the functional criterion, is obtaining the best ratio of strength to construction weight. Using high milling speeds enables economical manufacturing of integral components by reducing machining time, but it also improves the quality of the machined surface. It is caused by the fact that cutting forces are significantly lower for high cutting speeds than for standard machining techniques.

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.

THE CHARACTERISTICS OF FUNCTIONAL PROPERTIES OF THE MACHINED SURFACE BASED ON THE TOPOGRAPHY NON-PARAMETRIC AND PARAMETRIC DESCRIPTIONS

Tribologia ◽  
2019 ◽  
Vol 288 (6) ◽  
pp. 65-71
Author(s):  
Magdalena Niemczewska-Wójcik ◽  
Grzegorz Gawłowski
Keyword(s):  
Titanium Alloy ◽  
Surface Topography ◽  
Functional Properties ◽  
Material Properties ◽  
Interference Microscope ◽  
Machined Surface ◽  
Machine Material ◽  
Measuring Devices ◽  
Parametric Description ◽  
Scanning Electron

The shaping of the functional properties of the surface of an object in a technological process plays a key role in the later operation of this object. The paper presents the results of the tests performed on the surface topography of objects made of a selected hard-to-machine material, i.e., titanium alloy. Two measuring devices were used in the research, an interference microscope, and a scanning electron microscope, which enabled the comprehensive (nonparametric and parametric) description of surface topography obtained for three different finishing parameters. It was noted that, in addition to material properties, in the evaluation of the functional properties of a surface, it is important to carry out not only the qualitative, but also quantitative analysis of the machined surface topography.

scholarly journals Chatter Suppression and Stability Analysis of Rotary Ultrasonic Milling Titanium Alloy Thin-walled Workpiece

2021 ◽  
Author(s):  
Lianjun Sun ◽  
Kan Zheng ◽  
Wenhe Liao
Keyword(s):  
Titanium Alloy ◽  
Stability Analysis ◽  
Degrees Of Freedom ◽  
Machined Surface ◽  
Thin Walled Structures ◽  
Chatter Suppression ◽  
Ultrasonic Milling ◽  
Thin Walled ◽  
The Stability ◽  
Rotary Ultrasonic Milling

Abstract Titanium alloy and its thin-walled structures are widely used in the aerospace field. Aiming at the processing chatter and difficult-to-machine problem of titanium alloy thin-walled workpieces, rotary ultrasonic milling technology (RUM) is employed to restrict machining vibration in this paper. Firstly, the titanium alloy web with low stiffness is equivalent to a mass-spring-damping system with three degrees of freedom for describing its dynamic characteristics. Then, a novel stability analysis method is proposed for RUM thin-walled workpiece (RUM-tww) through defining an ultrasonic function angle. Furthermore, RUM-tww stability lobe diagrams (SLDs) are achieved based on the semi-discrete method (SDM). The simulation results show that the milling stability of titanium alloy webs is improved effectively under the effect of ultrasonic vibration energy. Compared with conventional milling thin-walled workpiece (CM-tww), the stability region of RUM-tww is increased by 80.32% within the spindle speed from 1000r/min to 5000r/min. Finally, milling experiments are carried out to verify the validity and rationality of SLDs via analyzing chatter marks, cutter marks and flatness on the machined surface. The experimental results are in good agreement with the theoretical prediction.

scholarly journals Influence of turning tool wear on the surface integrity and anti-fatigue behavior of Ti1023

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110112
Author(s):  
Li Xun ◽  
Wang Ziming ◽  
Yang Shenliang ◽  
Guo Zhiyuan ◽  
Zhou Yongxin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Plastic Deformation ◽  
Titanium Alloy ◽  
Fatigue Life ◽  
Tool Wear ◽  
Surface Integrity ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Machined Surface ◽  
Deformation Layer

Titanium alloy Ti1023 is a typical difficult-to-cut material. Tool wear is easy to occur in machining Ti1023, which has a significant negative effect on surface integrity. Turning is one of the common methods to machine Ti1023 parts and machined surface integrity has a direct influence on the fatigue life of parts. To control surface integrity and improve anti-fatigue behavior of Ti1023 parts, it has an important significance to study the influence of tool wear on the surface integrity and fatigue life of Ti1023 in turning. Therefore, the effect of tool wear on the surface roughness, microhardness, residual stress, and plastic deformation layer of Ti1023 workpieces by turning and low-cycle fatigue tests were studied. Meanwhile, the influence mechanism of surface integrity on anti-fatigue behavior also was analyzed. The experimental results show that the change of surface roughness caused by worn tools has the most influence on anti-fatigue behavior when the tool wear VB is from 0.05 to 0.25 mm. On the other hand, the plastic deformation layer on the machined surface could properly improve the anti-fatigue behavior of specimens that were proved in the experiments. However, the higher surface roughness and significant surface defects on surface machined utilizing the worn tool with VB = 0.30 mm, which leads the anti-fatigue behavior of specimens to decrease sharply. Therefore, to ensure the anti-fatigue behavior of parts, the value of turning tool wear VB must be rigorously controlled under 0.30 mm during finishing machining of titanium alloy Ti1023.

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.

Research on chatter stability in milling and parameter optimization based on process damping

2017 ◽  
Vol 24 (12) ◽  
pp. 2642-2655 ◽  
Author(s):  
Lida Zhu ◽  
Baoguang Liu ◽  
Hongyu Chen
Keyword(s):  
Surface Roughness ◽  
Frequency Method ◽  
Processing Efficiency ◽  
Machined Surface ◽  
Process Damping ◽  
Analysis Methodology ◽  
Optimization Of Process Parameters ◽  
Orthogonal Experiments ◽  
Cutting Chatter ◽  
The Stability

Cutting stability is the prerequisite to ensure efficient and high-precision machining, resulting in poor surface quality and damaged tool, which is the basis for the optimization of process parameters and improvement of processing efficiency. Aiming at process damping caused by interference between a tool flank face and a machined surface of part, the dynamic model and critical condition of stability is proposed in the paper. The frequency method is applied to solve the stability of the cutting chatter, and the correctness of the model is validated by experiments. Moreover, through orthogonal experiments, regression analysis methodology are adopted to establish a prediction model of surface roughness and finally combined with the study findings on milling stability based on process damping and surface roughness, achieved optimization of the milling parameters by genetic optimization algorithm. This conclusion provides a theoretical foundation and reference for the milling mechanism research.

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