Dynamic Models of Stability Lobes of Milling Thin-Walled Plates

2012 ◽  
Vol 443-444 ◽  
pp. 622-627
Author(s):  
Hai Long Ma ◽  
Ai Jun Tang ◽  
Qing Kui Chen

In the process of milling thin-walled plate, chatter is one of the major limitations on productivity and part quality even for high speed and high precision milling machines. Therefore, it is necessary to avoid chatter with a suitable choice of cutting condition. This paper studies the dynamic stability models of milling the thin-walled plate by analyzing the geometrical relationship of cutting, and derives the mathematic expressions in theory. Moreover, this paper develops a three-dimensional lobes diagram of the spindle speed, the axial depth and the radial depth. Through the three-dimensional lobes, it is possible to choose the appropriate cutting parameters according to the dynamic behavior of the chatter system.

2012 ◽  
Vol 490-495 ◽  
pp. 2829-2833
Author(s):  
Hai Long Ma ◽  
Ai Jun Tang ◽  
Qing Kui Chen

In the process of milling thin-walled plate, chatter is one of the major limitations on productivity and part quality even for high speed and high precision milling machines. Therefore, it is necessary to avoid chatter with a suitable choice of cutting condition. This paper studies the dynamic stability models of milling the thin-walled plate by analyzing the geometrical relationship of cutting, and derives the mathematic expressions in theory. Moreover, this paper develops a three-dimensional lobes diagram of the spindle speed, the axial depth and the radial depth. Through the three-dimensional lobes, it is possible to choose the appropriate cutting parameters according to the dynamic behavior of the chatter system.


Mechanik ◽  
2017 ◽  
Vol 90 (8-9) ◽  
pp. 726-729 ◽  
Author(s):  
Paweł Bałon ◽  
Edward Rejman ◽  
Robert Smusz ◽  
Bartłomiej Kiełbasa

Machining operations of thin-walled elements generate a lot of production process issues related to deformations and elastic and plastic displacements of the workpiece. Due to displacements of the milled workpiece, vibrations can occur, and thus, geometric errors may occur on surface in the structure of the workpiece. Furthermore, plastic deformation can also cause shape problems and be a source of internal stresses in the surface layer, which are highly difficult to remove and lead to deformation of the workpiece after machining. Consequently, this leads to an increase in the manufacturing costs of machining operations, especially of thin-walled elements, due to shortages and increased manufacturing time. It is recommended that multiple methods for minimizing machining errors be utilized to improve the quality of thin walled elements, such as: optimization of the machining strategy, increase of the cutting speed vc, optimization of cutting parameters, especially feed per blade fz, the radial depth of cut ae due to the minimization of the cutting force component perpendicular to the surface of the milled wall.


2006 ◽  
Vol 315-316 ◽  
pp. 319-323 ◽  
Author(s):  
Z.L. Hu ◽  
Cheng Yong Wang ◽  
L. Zhou ◽  
H. Fu ◽  
J. Chen

Graphite electrode material has been extensively used for thin-walled electrode manufacturing, due to its typical brittleness, HSM becomes the main process method to obtain higher productivity and good surface finish. According to the structure characteristics of the thin-walled graphite electrode and the problems arising in its high-speed milling, through high-speed milling experiments, researches have been done into the effect of the main cutting parameters on cutting forces, which include cutting speed, feed per tooth, radial cutting depth, axial cutting depth, down or up milling. Finally, cutting parameters optimization strategies of high-speed milling of thin-walled graphite electrode aiming to obtain higher efficiency and high quality are presented as follows: down-cut mode, moderate radial depth of cut and flat endmill should be adopted in high-speed milling of graphite electrode.


2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Mohd Shahfizal Ruslan ◽  
Kamal Othman ◽  
Jaharah A.Ghani ◽  
Mohd Shahir Kassim ◽  
Che Hassan Che Haron

Magnesium alloy is a material with a high strength to weight ratio and is suitable for various applications such as in automotive, aerospace, electronics, industrial, biomedical and sports. Most end products require a mirror-like finish, therefore, this paper will present how a mirror-like finishing can be achieved using a high speed face milling that is equivalent to the manual polishing process. The high speed cutting regime for magnesium alloy was studied at the range of 900-1400 m/min, and the feed rate for finishing at 0.03-0.09 mm/tooth. The surface roughness found for this range of cutting parameters were between 0.061-0.133 µm, which is less than the 0.5µm that can be obtained by manual polishing. Furthermore, from the S/N ratio plots, the optimum cutting condition for the surface roughness can be achieved at a cutting speed of 1100 m/min, feed rate 0.03 mm/tooth, axial depth of cut of 0.20 mm and radial depth of cut of 10 mm. From the experimental result the lowest surface roughness of 0.061µm was obtained at 900 m/min with the same conditions for other cutting parameters. This study revealed that by milling AZ91D at a high speed cutting, it is possible to eliminate the polishing process to achieve a mirror-like finishing.


2013 ◽  
Vol 300-301 ◽  
pp. 62-67
Author(s):  
Kun Ye ◽  
Ren Xian Li

Cutting is an effective device to reduce crosswind loads acting on trains. The cutting depth, width and gradient of slope are important factors for design and construction of cutting. Based on numerical analysis methods of three-dimensional viscous incompressible aerodynamics equations, aerodynamic side forces and yawing moments acting on the high-speed train, with different depths and widths of cutting,are calculated and analyzed under crosswinds,meanwhile the relationship of the gradient of cutting slope and transverse aerodynamic forces acting on trains are also studied. Simulation results show that aerodynamic side forces and yawing moments acting on the train(the first, middle and rear train)decrease with the increase of cutting depth. The relationship between transverse forces (moments) coefficients acting on the three sections and the cutting depth basically is the three cubed relation. The bigger is cutting width,the worse is running stability of train. The relationship between yawing moments coefficients acting each body of the train and the cutting width approximately is the three cubed relation. The transverse Aerodynamic forces decreased gradually with the increase of the gradient of cutting slope, the relationship between yawing moments coefficients acting each body of the train and the gradient of cutting slope basically is the four cubed relation.


2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985318
Author(s):  
Amon Gasagara ◽  
Wuyin Jin ◽  
Angelique Uwimbabazi

In this article, a new model of regenerative vibrations due to the deflection of the cutting tool in turning is proposed. The previous study reported chatter as a result of cutting a wavy surface of the previous cut. The proposed model takes into account cutting forces as the main factor of tool deflection. A cantilever beam model is used to establish a numerical model of the tool deflection. Three-dimensional finite element method is used to estimate the tool permissible deflection under the action of the cutting load. To analyze the system dynamic behavior, 1-degree-of-freedom model is used. MATLAB is used to compute the system time series from the initial value using fourth-order Runge–Kutta numerical integration. A straight hard turning with minimal fluid application experiment is used to obtain cutting forces under stable and chatter conditions. A single-point cutting tool made from high-speed steel is used for cutting. Experiment results showed that for the cutting parameters above 0.1mm/rev feed and [Formula: see text]mm depth of cut, the system develops fluctuations and higher chatter vibration frequency. Dynamic model vibration results showed that the cutting tool deflection induces chatter vibrations which transit from periodic, quasi-periodic, and chaotic type.


2009 ◽  
Vol 69-70 ◽  
pp. 428-432 ◽  
Author(s):  
Qing Hua Song ◽  
Yi Wan ◽  
Shui Qing Yu ◽  
Xing Ai ◽  
J.Y. Pang

A method for predicting the stability of thin-walled workpiece milling process is described. The proposed approach takes into account the dynamic characteristics of workpiece changing with tool positions. A dedicated thin-walled workpiece representative of a typical industrial application is designed and modeled by finite element method (FEM). The workpiece frequency response function (FRF) depending on tool positions is obtained. A specific 3D stability chart (SC) for different spindle speeds and different tool positions is then elaborated by scanning the dynamic properties of workpiece along the machined direction throughout the machining process. The dynamic optimization of cutting parameters for increasing the chatter free material removal rate and surface finish is presented through considering the chatter vibration and forced vibration. The investigations are compared and verified by high speed milling experiments with flexible workpiece.


Author(s):  
M.A. Baburin ◽  
V.D. Baskakov ◽  
S.V. Eliseev ◽  
K.A. Karnaukhov ◽  
V.A. Tarasov

The main factors controlling the formation of the stern of explosively formed projectiles are investigated using numerical calculations in a three-dimensional formulation of a problem. To form folds in the stern, it is proposed to use thin-walled spherical segments with a peripheral thickness deviation in terms of decreasing or increasing with respect to the thickness in the central part. The configurations of explosively formed projectiles with inclined folds in the stern are shown, and it is proposed to describe the fold inclination by two angles of its position. The effect of folds in the stern on the change in aerodynamic coefficients for a wide range of angle of attack is numerically studied. The angular velocity of the axial rotation of explosively formed projectiles with inclined folds in the stern is estimated based on the Newton method and considering the angles of its position. The results obtained are of interest to specialists working in the field of physics of explosion and high-speed impact, as well as those dealing with aerodynamics of aircrafts, mainly of axisymmetric shape


Author(s):  
Rui Zhang ◽  
Haitao Wang ◽  
Guiyin Zeng ◽  
Changhai Zhou ◽  
Runduo Pan ◽  
...  

The Ostrich is a native bird of Africa, and is highly accomplished in terrestrial locomotion in desert and grassland environments. The foot is an important segment in the ostrich body, critical for damping vibration, absorbing energy, and maintaining balance; however, detailed information on the ostrich foot is sparse. In this study, the gross anatomy of locomotor system of the ostrich foot was investigated using dissection and medical scan modeling. The paper contains a detailed study of the organizational structure and relative positional relationship of bones, tendons, and ligaments, which can be used for further three-dimensional (3D) reconstruction, providing a solid foundation for the research of high speed, heavy load, and shock absorption mechanisms. The study also provides a theoretical basis for the research of robot travelling mechanisms and vehicles traversing desert or planetary terrain.


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