scholarly journals Research on Cutting Performance in High-speed Milling of TC11 Titanium Alloy Using Self-propelled Rotary Milling Cutters

Author(s):  
Yujiang Lu ◽  
Tao Chen

Abstract Titanium alloy materials, with excellent chemical and physical properties, are widely applied to the manufacture of key components in the aerospace industry. Nevertheless, its hard-to-machine characteristic causes various problems in the machining process, such as severe tool wear, difficulty to ensure good surface quality, etc. To achieve high efficiency and quality of machining titanium alloy materials, this paper conducted an experimental research on the high-speed milling of TC11 titanium alloy with self-propelled rotary milling cutters. In the work, the wear mechanism of self-propelled rotary milling cutters was explored, the influence of milling velocity was analyzed on the cutting process, and the variation laws were obtained of milling forces, chip morphology and machined surface quality with the milling length. The results showed that in the early and middle stages of milling, the insert coating peeled off evenly under the joint action of abrasive and adhesive wear mechanisms. As the milling length increased, the dense notches occurred on the cutting edge of the cutter, the wear mechanism converted gradually into fatigue wear, and furthermore coating started peeling off the cutting edge with the occurrence of thermal fatigue cracks on the insert. As the milling length was further extended, the milling forces tended to intensify, the chip deformation worsened, and the obvious cracks occurred at the bottom of chips. Moreover, the rise in milling velocity reduced the tool wear resistance, increased obviously the milling forces and the surface roughness.

2021 ◽  
Author(s):  
Qimeng Liu ◽  
Jinkai Xu ◽  
Huadong Yu

Abstract Large-scale slender beam structures with weak stiffness are widely used in the aviation field. There will be a great deformation problem in machining because the overall stiffness of slender beam parts is lower. Firstly, the cutting mechanism and stability theory of the Ti6Al4V material are analyzed, and then the auxiliary support is carried out according to the machining characteristics of the slender beam structure. The feasibility of the deformation suppression measures for the slender beam is verified by experiments. The experimental analysis shows that on the basis of fulcrum auxiliary support, the filling of paraffin melt material is capable of increasing the damping of the whole system, improving the overall stiffness of the machining system, and inhibiting the chatter effect of machining. This method is effective to greatly improve the accuracy and efficiency during machining of slender beam parts. On the premise of the method of processing support with the combination of fulcrum and paraffin, if the tool wear is effectively controlled, the high precision machining of large-scale slender beams can be realized effectively, and the machining deformation of slender beams can be reduced. Although high speed milling has excellent machining effect on the machining accuracy of titanium alloy materials, severe tool wear is observed during high-speed milling of titanium alloy materials. Therefore, high-speed milling of titanium alloy slender beam is suitable to be carried out in the finishing process, which can effectively control tool wear and improve the machining accuracy of parts. Finally, the process verification of typical weak stiffness slender beam skeleton parts is carried out. Through the theoretical and technical support of the experimental scheme, the machining of large-scale slender beam structure parts with weak stiffness is realized.


Author(s):  
Tao Chen ◽  
Weijie Gao ◽  
Guangyue Wang ◽  
Xianli Liu

Torus cutters are increasingly used in machining high-hardness materials because of high processing efficiency. However, due to the large hardness variation in assembled hardened steel workpiece, the tool wear occurs easily in machining process. This severely affects the machined surface quality. Here, we conduct a research on the tool wear and the machined surface quality in milling assembled hardened steel mold with a torus cutter. The experimental results show the abrasive wear mechanism dominates the initial tool wear stage of the torus cutter. As the tool wear intensifies, the adhesive wear gradually occurs due to the effect of alternating stress and impact load. Thus, the mixing effect of the abrasive and adhesive wears further accelerates tool wear, resulting in occurrence of obvious crater wear band on the rake face and coating tearing area on the flank face. Finally, the cutter is damaged by the fatigue wear mechanism, reducing seriously the cutting performance. With increase of flank wear, moreover, there are increasingly obvious differences in both the surface morphology and the cutting force at the two sides of the joint seam of the assembled hardened steel parts, including larger height difference at the two sides of the joint seam and sudden change of cutting force, as a result, leading to decreasing cutting stability and deteriorating seriously machined surface quality.


Author(s):  
Emel Kuram

Tool coatings can improve the machinability performance of difficult-to-cut materials such as titanium alloys. Therefore, in the current work, high-speed milling of Ti6Al4V titanium alloy was carried out to determine the performance of various coated cutting tools. Five types of coated carbide inserts – monolayer TiCN, AlTiN, TiAlN and two layers TiCN + TiN and AlTiN + TiN, which were deposited by physical vapour deposition – were employed in the experiments. Tool wear, cutting force, surface roughness and chip morphology were evaluated and compared for different coated tools. To understand the tool wear modes and mechanisms, detailed scanning electron microscope analysis combined with energy dispersive X-ray of the worn inserts were conducted. Abrasion, adhesion, chipping and mechanical crack on flank face and coating delamination, adhesion and crater wear on rake face were observed during high-speed milling of Ti6Al4V titanium alloy. In terms of tool wear, the lowest value was obtained with TiCN-coated insert. It was also found that at the beginning of the machining pass TiAlN-coated insert and at the end of machining TiCN-coated insert gave the lowest cutting force and surface roughness values. No change in chip morphology was observed with different coated inserts.


2017 ◽  
Author(s):  
Hongliang Shi ◽  
Zhichao Wang ◽  
Huanhuan Ren ◽  
Haoteng Yuan

2016 ◽  
Vol 693 ◽  
pp. 1129-1134
Author(s):  
Zhao Ju Zhu ◽  
Jie Sun ◽  
Lai Xiao Lu

A series of research on the interactions among tool wear, cutting force and cutting vibration were conducted through high speed milling experiment in this paper, which objected the titanium alloy as difficult-to-cut materials. The results showed that the increasing of tool wear led to enlarging the cutting force and cutting vibration; and vice versa, the increasing of cutting force and cutting vibration aggravated the tool wear in the process of machining. Besides, the variation trend of tool wear with cutting was similar to the trend of cutting force, while the variation trend between cutting vibration and tool wear was different. Especially in the sharply cutting tool wear stage, the influence of tool wear on cutting vibration became more complicated.


2006 ◽  
Vol 532-533 ◽  
pp. 644-647
Author(s):  
Yi Ping Zhang ◽  
Jiu Hua Xu ◽  
Guo Sheng Geng

Ti-6.5Al-2Zr-1Mo-1V is a near alpha titanium alloy strengthened by solid solution with Al and other components. In this study, a series of experiments on tool wear and surface integrity in high speed milling (HSM) of this alloy were carried out. The tool lives under different cutting speeds were studied and the corresponding empirical equation of tool life was derived. Additionally, the wear mechanism of cutting tools was also discussed. Finally, surface integrity, including surface roughness, metallograph, work hardening and residual stresses, were examined and analysed. The result shows that good surface quality of workpiece could be obtained in HSM of the alloy.


2012 ◽  
Vol 723 ◽  
pp. 177-181 ◽  
Author(s):  
Qi Shi ◽  
Yin Fei Yang ◽  
Ning He ◽  
Liang Li ◽  
Wei Zhao

TC4-DT is a new damage-tolerant titanium alloy. In the paper, a series of experiments on tool wear and surface integrity in high speed milling of the alloy were carried out. The tool lives of different tool materials were studied and the wear mechanism of cutting tools was also investigated. Then surface integrity, including surface roughness, microhardness and metallurgical structure was studied and analyzed in high speed milling at different tool wear status. Results showed that K10 is the most suitable cutting tool after considering a combination of factors. And good surface integrity could be obtained in high speed milling of TC4-DT under all cutting situations. In addition, even with acutely worn stages, there has been no so-called serious hardening layer (or white layer) according to the study of microhardness and metallurgical structure beneath the machined surface.


Author(s):  
P. Krishnakumar ◽  
K. Rameshkumar ◽  
K. I. Ramachandran

Mechanical and chemical properties of titanium alloy have led to its wide range of applications in aerospace and biomedical industries. The heat generation and its transfer from the cutting zone are critical in machining of titanium alloys. The process of transferring heat from the primary cutting zone is difficult due to poor thermal conductivity of titanium alloy, and it will lead to rapid tool wear and poor surface finish. An effective tool monitoring system is essential to predict such variations during machining process. In this study, using a high-speed precision mill, experiments are conducted under optimum cutting conditions with an objective of maximizing the life of tungsten carbide tool. Tool wear profile is established and tool conditions are arrived on the basis of the surface roughness. Acoustic emission (AE) signals are captured using an AE sensor during machining of titanium alloy. Statistical features are extracted in time and frequency domain. Features that contain rich information about the tool conditions are selected using J48 decision tree (DT) algorithm. Tool condition classification abilities of DT and support vector machines are studied in time and frequency domains.


2014 ◽  
Vol 67 (3) ◽  
Author(s):  
H. Safari ◽  
S. Izman

Surface quality is one of the most critical restraints for determining cutting parameters and selecting of machining process in metal cutting process. In this study, the effects of cutting parameters and tool wear on the surface and sub-surface quality of high speed dry end milling Ti-6Al-4V were investigated. PVD Coated carbide tools were used under different high cutting speeds and feed rates. The quality of the machined surface and corresponding alteration on the sub-surface and entry/exit edges were characterized through scanning electron microscopy. The results showed that the better surface quality was obtained when machining at higher cutting speeds and feed rates. High speed dry end milling using the worn tool causes to plastic deformation of the alloy which is resulted in developing the lamellae on the surface and causing poor surface finish. Worn tools with the uniform tool wear land generated better surface quality compare to those with chipping and flaking on the tool edge surface. Tool wear is suggested as the other contributing factor in developing entry and exit edge damages. The results of sub-surface alteration measurement revealed that the worn tool enhanced the sub-surface alteration resulted in 45% increase in plastic deformation compare to the new tool.


2014 ◽  
Vol 800-801 ◽  
pp. 526-530 ◽  
Author(s):  
Shu Cai Yang ◽  
Yu Hua Zhang ◽  
Quan Wan ◽  
Jian Jun Chen ◽  
Chuang Feng

The milling experiments were carried out using TiAlN and PCD coated carbide tools in high speed milling Ti6Al4V to compare and analyze tool wear and tool life of the two kinds of coating carbide tools. In addition, the effect of cooling and lubricating on tool wear is also studied. The results showed that fluid environment is not suitable for milling Ti6Al4V. PCD coating carbide tool can effectively increase the life of tool in high speed milling of Ti6Al4V.


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