Papers by Keyword: Grinding System

Abstract: To solve the interference problem during the grinding process of large lead ball nut, a new forming grinding system based on flexible shaft has been designed in this paper. The paper analyzed and compared with three grinding methods including reducing setting angle, deflecting setting angle and adopting flexible shaft grinding system to figure out their influence on possibility, precision and efficiency of grinding. The result shows that the flexible shaft grinding system designed can avoid interference effectively. Additionally, it can also meet the requirement of efficiency and precision when grinding the large lead ball nut.

Abstract: An orbital grinding system is developed for manufacturing high precision crankshafts for 5ton-5m class ship engines. Structural analysis is carried out by 3D modeling and FEM simulation using a commercial software. The grinding system can conduct high precision grinding process for crankshafts of ship engines as well as normal small crankshafts.

Abstract: A crankshaft is the most critical component, and it can dominate the life of the engine. Nowadays an orbital grinding is widely used to grind a crankshaft. In this study, static analysis is done to find deformation of an orbital grinding system due to weight, modal analysis is done to obtain the natural frequencies, and harmonic analysis is done to investigate the compliance. It is found that all the results show that first frequencies are found to be near 70-80Hz. The machine will be weak to vibration near 70-80Hz. It is also found that the peak value of x compliance is smaller than that for other axes, and grinding in the x direction will be more stable than grinding in other direction.

Abstract: In this study, Zingiber officinale (ginger) rhizome fine particles were prepared by using food processor, hammer mill and planetary ball mill and tested for their physical and thermal properties. The physical changes by means of particle size, surface morphology, FT-IR and thermal stability (TGA) were investigated. The size reduction method had a distinct effect on physical and thermal properties of ginger rhizome tested. Average particle size of ginger rhizome after using food processor and hammer mill was around 50µm and 20µm respectively while after using planetary ball mill the ginger rhizome was successfully reduced to nanoscale (222.3 nm). Higher degree of granule surface fractured was observed as a result of a planetary ball milling process based on FESEM images. There were also some notable differences of FT-IR spectra detected. By comparing the spectra, the stretching vibration peak of OH at 3292 cm^-1[U1] and the symmetric stretching vibration peak of the NO₂ and C=C at 1369 – 1639.51cm-1 for ginger rhizome ground using food processor were disappeared. Yet, presence of possibly strong alkenes group (in the range 2850 – 2970cm-1) were observed in all samples tested. Ginger rhizome particles obtained from hammer milling process were found to be more stable to thermal effect where the decomposed temperature was 276.64°C as compared to samples milling using food processor and planetary ball mill. These results would provide useful insight for exploring the potential applications of ginger rhizome fine powder as functional food ingredient as well as in pharmaceutical applications. [U1]Check typing of superscript.

Abstract: In this paper we present the results of numerical simulation of the stiffness of gear grinding system using finite element method (FEM). Since the rigidity of system can be characterized by two aspects, one static and one dynamic. We will concentrate on the low stiffness of components inside the system to find errors that may affect the precision on the horizontal, vertical and rotational direction of technological system elements.

Abstract: In mineral processing the high material volumes yield the fact that benefits of even small improvements in the production quality and product efficiency are remarkable. During the operation of the mineral material processing, the grinding circuit (GC) is the key unit and its product particle size and circulating load are two controlled indexes directly related to the quality and efficiency of the whole mineral material processing. Therefore, an appropriate control of GC is especially significant to improve the operation performance of the mineral material processing. Due to the GCs are essentially multivariable dynamic systems with high interaction among process variables. It is hard to improve the quality and efficiency in the mineral material processing by controlling the grinding system with the conventional methods. In this paper, a novel multivariable decoupling control scheme is adopted to handle such intricate process. Simulations have shown the proposed method can greatly improve the production quality and product efficiency of the mineral material processing.

Abstract: In order to decrease the development costs, shorten the developing cycle, improve the overall performance and reduce the environmental pollution of the wafer precision grinding machine, the structure, transmission, movement of grinding system for wafer precision grinding machine is analyzed based on mechanical system mechanics, the three-dimensional model of the grinding system is established, based on frame animation technology and via secondary development of Pro/E in the environment of VS 2008, the virtual prototype of grinding system for wafer precision grinding machine is developed, the kinematics and dynamics simulation of the grinding system is realized.

Abstract: According to the complex characteristics of grinding process, a method of fuzzy internal model control (FIMC) is put forward. By adjusting the filter parameters t in internal model control on line, the problem that the control performance is poor in the condition of internal model mismatching, and through simulation, it shows that this method has short adjusting time, small overshoot, and also is feasible and effective.

Abstract: In this paper, the mathematical model with two associated coordinates is established for two-dimension ultrasonic vibration group system by impedance analysis, and natural frequency equation of 2D vibration system is deduced by which the influence of natural frequency change of individual components on the natural frequency of group system is analyzed. Amplitude-frequency characteristics of system were tested which verified the correctness of the theory. In simulation experiment on large plate under two-dimensional ultrasonic vibration grinding, superimposed tracks of a number of irregular ovals exist in vibrating plane, that is different from previous research that only one simply oval track exists in the vibrating plane apparently. The results supply a reliable theoretical and experimental basis for the further discussions on the abrasive removal mechanism under two-dimensional ultrasonic vibration.

Abstract: Systems “spindle – bearings” will inevitably have some errors and discrepancies in the dimensions and form of elements. These inaccuracies cause spindle’s run out. The run out is a complex periodic process which may include three types of frequency components: with frequencies exceeding the spindle’s rotary frequency, with frequency equal to the spindle’s rotary frequency and with frequencies lower that the spindle’s rotary frequency. Each individual frequency component may be caused by eccentricity or out-of-roundness of the inner race, out-of-roundness of the outer race, spread of ball diameters, and inaccuracy of their form. Self-adjustable pad-type bearings are sensitive to technological, service and construction perturbations. This is characteristic of vortex trajectories of the spindles. Character of these trajectories depends on the thickness of lubricant film over the pad supports and on the geometrical precision of the spindle journal and pads (segments). Geometrical precision under a high unbalance of the grinding wheel is crucial for functional quality, size and form of the orbit. Geometrical precision of trajectories and its state are subject to change depending on a number of parameters especially on the rigidity of the lubricant film and dynamic system.