Polishing surface integrity of TC17 aeroengine blades

De Liu,Yaoyao Shi,Xiaojun Lin,Chao Xian,Zhiyang Gu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.2

Aeroengine blades have high requirements for surface integrity. Through the flexible polishing of TC17 engine blades, the surface integrity of polished blades is improved. First, the influence of process parameters on polishing force and polishing temperature is analyzed through experiments. The influence of parameters on surface roughness is analyzed, and the relationship between wear debris shape and surface morphology under different process parameters are analyzed from the microscopic level. Second, the influence of process parameters on the residual stress of the polished surface is analyzed in accordance with the polishing force and polishing temperature. Then, the variation of the residual stress of the blade after milling and polishing is analyzed. In addition, the microstructure of the metamorphic layer after milling and polishing is analyzed. Experimental results show that reasonable polishing parameters can effectively improve the surface integrity of the blade.

Roughness modeling for polishing an aero-engine blade with an abrasive cloth wheel

Chao Xian,Yaoyao Shi,Xiaojun Lin,De Liu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.8

Roughness is a crucial factor that determines workpiece quality. In this paper, the time-domain signals of polishing force for polishing an aero-engine blade with an abrasive cloth wheel were experimentally obtained, and the contact arc lengths were determined based on these signals. A mathematical model for the representative R a of blade surface roughness after polishing was then established, and this model is only related to the contact arc length. This model was experimentally verified, and the prediction results agree well with the measurement results.

An adaptive flexible polishing path programming method of the blisk blade using elastic grinding tools

Wenbo Huai,Yaoyao Shi,Hong Tang,Xiaojun Lin 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.7

As for blisk blade profile polishing, the “five-axis numerical control + flexible grinding head + elastic grinding tool” polishing process equipment has advantages of high precision, little interference, good adaptivity, etc.; in order that the elastic grinding tool (abrasive cloth wheel) can effectively fit in with the blade profile in the polishing process and polishing quality and efficiency can be improved, a polishing path programming method of the elastic grinding tool was studied, feed mode of the elastic grinding tool and parametric method of the blade profile were proposed, and calculation methods of offset surface, polishing spacing, polishing step size and cutter-axis vector were given; this polishing path programming method makes it possible for the flexible spindle mechanism keeps a reasonable pose during the polishing process so that the elastic grinding tool can not only effectively fit in with the blade profile but also the polishing force direction of the elastic grinding tool is basically identical with normal vector direction of the polishing point; the polishing test results indicate that: After polishing, blade surface roughness is smaller than 0.4 µm and blade profile tolerance is within the tolerance zone, thus satisfying technical requirements and indicating that the technology proposed in this paper can satisfy blisk blade profile polishing requirements.

Optimization of abrasive flow polishing process parameters for static blade ring based on response surface methodology

Zhao Tao,Shi Yaoyao,Lin Xiaojun,Huang Tianran 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.3

Static blade ring process technology is a key part for gas turbine manufacturing, and the surface quality of the static blade ring has great influence on a gas turbine. To improve surface roughness of static blade ring, abrasive flow polishing process technology is studied. First, the range of extrusion pressure is obtained by using ANSYS software to analyze the blade deformation. Then a simplified model of surface roughness is estabalished according to experimental results and ANOVA’s results. At the same time, the optimal polishing parameters are confirmed through the response surface methodology. Finally, the polishing experiment is carried out by using the optimal polishing parameters. The experimental results demonstrate that the surface roughness of static blade ring decreased greatly (nearly 14.7%) compared with result using normal parameters.

Parameter optimization of five-axis polishing using abrasive belt flap wheel for blisk blade

Junfeng Zhang,Yaoyao Shi,Xiaojun Lin,Zhishan Li 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.10

Considering the weak rigidity of blisk blades and the limited accessibility of blisk tunnels, polishing blisk blades is difficult when using tools with poor flexibility and large dimension. Hence, to reduce the surface roughness (SR) of a blisk blade, five-axis polishing method with abrasive belt flap wheel (ABFW) is employed to polish the blisk blade based on the analysis of the blisk structure and advantages of ABFW polishing. Polishing experiments based on central composite design are performed using ABFW. Response surface method (RSM) is employed to establish a predictive model between SR and various parameters, including ABFW size, contact force, spindle speed, and feed rate. Analysis of variance is then performed to evaluate the proposed model. The degree of influence of each factor on SR after polishing using ABFW is determined by plotting main effects. The interactions of polishing factors on SR are analyzed by RSM. Optimal parameters are obtained by response surface optimization. Finally, an experiment on blisk blade polishing using ABFW on a five-axis polishing machine is carried out for confirmation. Results indicate that the surface quality of the blisk blade after polishing is significantly improved, with SR being less than 0.4 μm.

Sensitivity of surface roughness to flexible polishing parameters of abrasive cloth wheel and their optimal intervals

Wenbo Huai,Yaoyao Shi,Hong Tang,Xiaojun Lin 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2

High-speed rotating abrasive cloth wheel is a highly flexible material that can be used to polish aviation engine blades. In this study, sensitivity and relative sensitivity to processing parameters were described on the basis of an empirical model of surface roughness to control the polishing of rough surfaces with abrasive cloth wheels. A mathematical model of the sensitivity and relative sensitivity of surface roughness to processing parameters was also established on the basis of an orthogonal test of polishing TC4 blade workpieces by utilizing abrasive cloth wheels. The sensitivity of the analytical method for processing parameter interval was examined, and the division principle and approach for the stable and unstable ranges of processing parameters were proposed. The influence curve of polishing parameters on surface roughness was obtained by combining the analyzed ranges in the orthogonal test. The optimization of processing parameter interval was also presented to identify the optimal intervals of surface-roughness-oriented polishing parameters of abrasive cloth wheels. The polishing test based on an aviation engine blade confirmed that the optimal intervals of the parameters were reliable. This research provides a basis for theoretical studies and tests to evaluate blade polishing technique with abrasive cloth wheels and surface roughness control.

Ganoderic acid A attenuates high‑fat‑diet‑induced liver injury in rats by regulating the lipid oxidation and liver inflammation

Fuli Liu,Kejian Shi,Jiaojiao Dong,Zhousheng Jin,Yiquan Wu,Yaoyao Cai,Tingting Lin,Qianqian Cai,Le Liu,Yujian Zhang 대한약학회 2020 Archives of Pharmacal Research Vol.43 No.7

Ganoderic Acid A (GA) has many pharmacologicaleffects such as anti-tumor, antibacterial, anti-inflammatory,and immunosuppressive effects. However, the protectiveeffect of GA on liver injury has not been reported. Thisstudy aimed to investigate the action of GA on insufficientmethionine and choline combined with high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) in rats. NAFLD model was established by insufficient methionineand choline combined with high fat feeding to rats. The levelsof Acetyl-CoA carboxylase, fatty acid synthase, sterolregulatory element binding protein, liver X receptors, AMPactivatedprotein kinase, peroxisome proliferator-activatedreceptor α, PPARg coactivator 1α and NF-κB pathway inthe liver were detected by western blot. The results of thisstudy demonstrated that the expression of GA can not onlysignificantly decrease the live weight and liver weight perbody weight of HFD mice, but also restore the alanine aminotransferase,aspartate aminotransferase, total bilirubinlevels, triglyceride and cholesterol in serum. In addition,the expression of GA increased the levels of high-densitylipoprotein cholesterol in serum, ameliorated pathologicalchanges and decreased NAS score of mice’s liver. In conclusion,the treatment with GA could improve NAFLD in ratsby regulating the levels of signaling events involved in freefatty acid production, lipid oxidation and liver inflammation.