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Gu J.,Shanghai University of Engineering Science | Wang D.,Shanghai University of Engineering Science | Xiao L.,Shanghai Aerospace Precision Machinery Research Institute | Li F.,Shanghai JiaoTong University | And 4 more authors.
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2016

The storage modulus and loss modulus of the wax during cooling process were measured by the advanced rheometric expansion system. The main modulus curves and wax relaxation time spectrum were calculated according to time-temperature equivalence principle. Finally, viscoelastic deformation of wax pattern during deposited process was predicted by using the finite element software Abaqus. © 2016, Journal Office of Special Casting and Nonferrous Alloys. All right reserved. Source


Gu J.,Shanghai University | Wang D.,Shanghai University | Xiao L.,Shanghai Aerospace Precision Machinery Research Institute | Li F.,Shanghai JiaoTong University | And 4 more authors.
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2016

Numerical simulation technology is an important method which based on the flow and solidifi-cation theory of polymer materials for investment casting process to research wax prepared. In this pa-per, we use experimental method to determine the basic performance parameters of wax. Firstly, use the capillary rheometer to test the rheological properties of wax with the Cross-WLF viscosity model to fit the viscosity model parameters. Secondly, the Netzsch type of differential scanning calorimeter was used to analysis the thermal properties of the wax. Finally, the indirect heat expansion analyzers was used to measure PVT properties of wax. By the performance of wax such as thermal, mechanical, rheological, compressibility, it can achieve numerical simulation during wax injection molding process, which can improve the dimensional accuracy and quality of wax pattern for investment casting, this laid a theoretical basis. © 2016, Journal Office of Special Casting and Nonferrous Alloys. All right reserved. Source


An Q.,Shanghai JiaoTong University | Wang C.,Shanghai JiaoTong University | Xu J.,Shanghai JiaoTong University | Liu P.,Shanghai Aerospace Precision Machinery Research Institute | Chen M.,Shanghai JiaoTong University
International Journal of Refractory Metals and Hard Materials | Year: 2014

High strength steel 30Cr3SiNiMoVA (30Cr3) is usually used to manufacture the key parts in aviation industry owing to its outstanding mechanical properties. However, 30Cr3 has poor machinability due to its high strength and high hardness. Hard milling is an efficient way in machining high strength steels. This paper investigated hard milling of 30Cr3 using a PVD-AlTiN coated cemented carbide tool with regard to cutting forces, surface roughness, chip formation and tool wear, respectively. The experimental results indicated that the increase of cutting speed from 70 to 110 m/min leads to direct reduction of cutting forces and improvement of surface finish, while both feed rate and depth of cut have negative effect on surface finish. The occurrence of oxidation on chip surfaces under high cutting temperature makes the chips show different colors which are strongly influenced by cutting speed. Saw-toothed chips were observed with the occurrence of the thermo-plastic instability within the primary shear zone. Micro-chipping and coating peeling were confirmed to be the primary tool failure modes. Serious abrasion wear and adhesive wear with some oxidative wear were confimed to be the main wear mode in hard milling of 30Cr3. © 2013 Elsevier Ltd. Source


He X.,Shanghai JiaoTong University | He X.,Shanghai Aerospace Precision Machinery Research Institute | Guo G.,Shanghai JiaoTong University | Li K.,Shanghai JiaoTong University | Chen M.,Shanghai JiaoTong University
Key Engineering Materials | Year: 2016

Slender shaft is of high slenderness ratio and bad rigidity. The factors, for example, cutting force, cutting heat, vibration and so on, which are produced in the processing, will affect directly the size precision of workpieces. In this research, slender shaft is 304 stainless steel bar, with length of 450mm and diameter of 10mm. In order to resolve the problem of slender shaft machining with CNC slant bed lathe not configured with the follow-rest, a self-made follow-rest was developed. With both ends clamped processing mode, it is possible to use the CNC lathe turning slender shaft. Moreover, better effect of turning of slender shaft can be attained if ultrasonic vibration cutting technology is involved. After turning process is completed, size accuracy is checked to evaluate the effect of self-made follow-rest and both ends clamped processing mode. In this study, the experimental results show that quality of the slender shaft processing has been significantly improved with the use of self-made follow-rest and both ends clamped processing mode, which has definite effects on solving the practical problems of processing. © 2016 Trans Tech Publications, Switzerland. Source


Song J.B.,Shanghai JiaoTong University | Wang C.Y.,Shanghai JiaoTong University | Zan L.,Shanghai Aerospace Precision Machinery Research Institute | Chen M.,Shanghai JiaoTong University
Materials Science Forum | Year: 2014

Ultra-high strength steel 30Cr3SiNiMoVA is a typical difficult-to-cut material. During the machining process of 30Cr3SiNiMoVA, tool wear is an important factor which needs to be investigated seriously. In this work, one kind of CVD coated tools was used to investigate the tool wear mechanism of face milling of Ultra-high Strength Steel 30Cr3SiNiMoVA. Cutting forces during the wear process were measured with a kistler dyna-mometer. Surface roughness and tool wear evolution were determined. © (2014) Trans Tech Publications, Switzerland. Source

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