Showing papers by "Jie Sun published in 2013"
TL;DR: In this article, the authors introduced the signal processing methods such as time domain, frequency domain, and time-frequency domain analysis to identify the chatter and select suitable cutting parameters to avoid chatter at high material removal rate (MRR).
Abstract: In metal cutting processes, the chatter may cause fast wear of tools and poor surface quality of the processed parts; it can happen on different cutting parameters, but how do we identify the chatter and how do we select suitable cutting parameters to avoid chatter at high material removal rate (MRR). In this paper, the signal processing methods such as time domain, frequency domain, and time–frequency domain analysis are introduced. The signals of cutting force that were collected in milling titanium alloy Ti–6Al–4V at variable cutting speeds varied from 80 to 360 m/min; signal analysis methods such as time domain, frequency domain, and time–frequency domain were put forward. Further analysis results reveal that the chatter occur when cutting speeds are 240 and 360 m/min, when the maximum value of cutting forces increase by 61.9–66.8%, the standard deviation increase by 84.1–86.1%, and the surface roughness increase by 34.2–40.5% compared with that of at 80 m/min. Detail signal d2 is employed to monitor cutting stability state from the result of wavelet analysis.
73 citations
TL;DR: In this article, the relationship between cutting force and tool flank wear of a solid carbide tool during the wet end milling of Ti6Al4V was investigated, and the results showed that the proposed mathematical model can help to predict 3D cutting force under the tool's flank wear effect with high accuracy.
Abstract: This paper presented a study of the relationship between cutting force and tool flank wear of solid carbide tool during the wet end milling Ti6Al4V. The modeling of 3D cutting force in end milling considering tool flank wear was discussed, which showed that for the given cutting conditions, tool geometries, and workpiece material, cutting force under the tool flank wear effect can be predicted easily and conveniently. In addition, the experimental work of end milling Ti6Al4V with solid carbide tool was developed to investigate the relationship between cutting force and tool flank wear, and comparison between experimental results and predicted results was discussed. The results showed that the proposed mathematical model can help to predict 3D cutting force under the tool flank wear effect with high accuracy.
34 citations
TL;DR: In this article, a high speed milling experiment by means of orthogonal method with four factors was conducted for aluminum alloy 7050-T7451, and the residual stresses on the surface and subsurface of the work pie were investigated.
Abstract: A high-speed milling experiment by means of orthogonal method with four factors was conducted for aluminum alloy 7050-T7451. The residual stresses (RS) on the surface and subsurface of the work pie...
30 citations
TL;DR: In this article, a new model for determining the undeformed chip thickness in milling process with higher accuracy is proposed, based on the true trochoid path of tool tooth, the true instantaneous chip thickness can be derived by solving the deduced transcendental equation.
Abstract: An accurate approach of the instantaneous undeformed chip thickness is a key issue for analyzing milling process. The presented models for approximating instantaneous undeformed chip thickness are oversimplified and complex for use in academic and manufacture practice. In this paper, a new model for determining the undeformed chip thickness in milling process with higher accuracy is proposed. According to the true trochoid path of tool tooth, the true instantaneous undeformed chip thickness can be derived by solving the deduced transcendental equation. An iterational algorithm is used to approach the value in the transcendental equation with infinitesimal calculation error. Our main contributions include that the accurate positions of the geometric points of the undeformed chip profile with different level of width of cut are analyzed and derived, as well as the accurate undeformed chip thicknesses of the chip cross-section profile are approached by iterative algorithm. Case studies with different parameter combinations show that the new model has a higher accuracy compared with the presented models. With this innovative approach, a method of accurate prediction of the geometric profile and thickness of the undeformed chip profile in milling process is provided.
27 citations
TL;DR: In this paper, the vibration reduction mechanism of variable pitch end mill was analyzed by the theory of energy balance of the frequency spectrum line for high-speed cutting of titanium alloy Ti6Al4V under dry and down-milling environment.
Abstract: The vibration reduction mechanism of variable pitch end mills was analyzed by the theory of energy balance of the frequency spectrum line. The variable pitch mill can reduce the forced vibration in the cutting process due to the uniform distribution of frequency spectrum line energy and lower peak energy of the cutting force. Aimed at the vibration phenomenon which restricted the efficiency in cutting aero material titanium alloy, high-speed cutting experiments of titanium alloy Ti6Al4V were set with variable and equal pitch mills under dry and down-milling environment. The influences of cutting speeds on cutting forces and tool vibration were analyzed at time domain and frequency domain, respectively, by which the vibration reduction mechanism of variable pitch mill was verified. Due to the misalignment of end mill no. 3, high-level cutting forces and tool vibration were caused by the unequal cutting load on each edge. It is found that severe tool vibration was produced under the cutting speed of 150 m/min because of low-frequency resonance in the cutting process.
20 citations
TL;DR: Results indicate that the ethanol pretreatment followed by APPJ treatment is a permanent surface treatment with negligible aging for at least five months.
Abstract: In order to investigate hydrophilic recovery of hydrophobic treatment of cellulose fibers, ramie fibers are ethanol-pretreated followed by atmospheric pressure plasma jet (APPJ) treatment using helium as the treatment gas and age for up to 150 days in 20 °C and 65% relative humidity. Scanning electron microscopy shows the fiber surfaces of the ethanol-pretreated + APPJ-treated group of freshly prepared, aged for 30 days, and aged for 150 days are covered with polypropylene matrix after fiber pullout tests. X-ray photoelectron spectroscopy shows that the freshly prepared ethanol-pretreated + APPJ-treated group has a 31% reduction in atomic ratio of oxygen to carbon and maintains at a similar level even after 150 days of aging. Water contact angle measurement demonstrates that the wettability of fiber surface of the freshly prepared ethanol-pretreated + APPJ-treated group drastically decreases and remains at the same lever after aging. Interfacial shear strength test reveals that the interfacial adhesion be...
8 citations
TL;DR: In this paper, a finite element analysis is made to the modal analysis of the impeller, and a finite-element model of a impeller with cracks is established, which provides a basis for modal calculation.
Abstract: In this paper, the finite element analysis is made to the modal analysis of the impeller, a finite element model of a impeller with cracks was established. This paper presents results of the modal of the compressor blade subjected to centrifugal force and aerodynamic equilibrium pressure. In this analysis, the numerical models without defects and also with cracks were defined. The simulation results showed that the centrifugal force due to rotational speed can greatly influence the frequency of the impeller. The distribution of two cracked blades effect the natural frequence of the impeller. When two cracked blades locate in the interval position, the increasing value of frequence is maximum. When the two cracked blades interval 150°, the increasing value of frequence is minimum. It provides a basis for modal calculation of the impeller.
TL;DR: In this article, two angles from design concept and design psychology at first to assumed, then the relations between design concepts and psychology are analyzed, the target is use of design psychology knowledge to improve the design concept better so as to lead a good design.
Abstract: The generation of design concept is the first step in the process of design which related the design direction and thematic. Design psychology is a new cross subject. Both seemed unrelated, actually, it is a close relationship between them. Design psychology is an auxiliary of helping Design concept creation. Design psychology is the basis and skills of the design concept. In this paper two angles from design concept and design psychology at first to assumed, then the relations between design concept and design psychology are analyzed. The target is use of design psychology‘s knowledge to improve the design concept better so as to lead a good design.
TL;DR: Easy to learn and easy to use of the product which are fully consider and won't have wrong operation in the design are advocated and shows that the design method of usability is easier to design a rational product with high performance and practical value.
Abstract: The usability design is also an important part in product design process. Product is a service, but we often confused about the operation of the product in our daily life. So far, the theoretical researches about the usability have been widely investigated. However, the methods of usability are seldom researched in the process of design. In this paper, easy to learn and easy to use of the product which are fully consider and won't have wrong operation in the design are advocated. Principles and affecting factors of usability are analyzed in the design. The methods of usability are proposed at the beginning of the design and in the process of late. According to the principles and influencing factors, it shows that the design method of usability is easier to design a rational product with high performance and practical value.
TL;DR: In this paper, a finite element analysis is made to the structure of the impeller and a finite-element model of a impeller with cracks is established, and the results of the stress analysis of the compressor blade subjected to centrifugal force and aerodynamic equilibrium pressure are presented.
Abstract: In this paper, the finite element analysis is made to the structure of the impeller, a finite element model of a impeller with cracks was established. This paper presents results of the stress analysis of the compressor blade subjected to centrifugal force and aerodynamic equilibrium pressure. A nonlinear finite element method was utilized to determine the stress state of the blades. In this analysis, the numerical models without defects and also with cracks were defined. The simulation results showed that high stresses occurred in the areas where the cracks initiated under both centrifugal force and aerodynamic equilibrium pressure. The distribution of two cracked blades can greatly influence the stress level of the impeller; when two cracked blades locate in the adjacent positions，the increasing value of stress is minimum. When the two cracked blades separated by 150°, the increasing value of stress is maximum. It provides a basis for strength calculation of the impeller.
TL;DR: In this paper, a purely analytical method based on the meshing theory is presented to establish the exact helical groove and circumferential cutting edge model of end mills, for the solution of its low design precision and efficiency problems.
Abstract: A purely analytical method, based on the meshing theory, is presented to establish the exact helical groove and circumferential cutting edge model of end mills, for the solution of its low design precision and efficiency problems. Firstly, a coordinate system to represent the relative space position relations between grinding wheels and end mills is built and the mathematical model of the helical groove is precisely calculated with a given wheel profile and relative movements between the wheel and the workpiece. Then, the rake angle, inner radius and wheel positions of machining the clearance faces is computed. Finally, a 3D model of the end mill is generated by using OpenGL.