Abstract: The use of fluids in grinding is necessary to carry out an optimized process that avoids any kind of damage in the ground workpieces. However, the use of fluids in machining processes presents some problems as the economic one and the environmental one. The present work analyzes the industrial viability of a new solution to avoid the use of fluids in grinding, the MCG system. This system combines the use of a MQL (Minimum Quantity Lubricant) commercial system and a gas supplied at low temperatures. In this case the grinding of a component of the engine of a competition motorcycle with the MCG (Minimum Coolant Grinding) system is compared with the classic fluid flow system.
Abstract: There has been increased interest in the use of advanced ceramic materials such as silicon carbide in the recent past, due to its unique physical and mechanical properties. However, the increase of the machining rate relies on the understanding of material removal mechanism on the microstructural scale and the relationship between the grinding characteristics and formation of surface/subsurface machining-induced damage. In this paper, grinding characteristics and surface integrity of SiC ground with diamond wheel on cylindrical grinding machine have been investigated. The grinding chip and the ground surface damage have been studied with scanning electron microscope (SEM). In particular the residual stress distribution has been analyzed by a single exposure technique d - sin2 (Ψ) method with the aid of powder X-ray diffractometer.
Abstract: In this work, grinding test was performed in terms of machining parameters, such as grinding speed, feed rate, etc., in order to study effect of ultrasonic vibration in grinding. The design of experiment (DOE) approach was used for an optimal condition of ultrasonic assisted grinding, which can minimize the grinding forces. In DOE, ultrasonic amplitude power, feed rate, and rotation speed of spindle were chosen as the major machining factors. The grinding forces were measured and compared between the conventional grinding and ultrasonic assisted grinding. From the experiment, it was found that the grinding forces decreased as the ultrasonic vibration power and the rotation speed of spindle increased while the grinding force was reduced as the feed rate increased. In addition, regression model was formulated for obtaining optimal grinding condition.
Abstract: In this paper, a ultrasonic horn, which can vibrate longitudinally with a frequency of 20㎑, was designed using finite element method (FEM). And the ultrasonic horn was fabricated for ultrasonic assisted grinding. To evaluate machining performance of the fabricated ultrasonic horn, grinding test was conducted on alumina ceramic (Al2O3). In the grinding test, grinding forces was measured and compared between the conventional grinding and the ultrasonic assisted grinding. The results showed that the grinding force in the ultrasonic grinding was lowered than the conventional grindign by 3~20%.
Abstract: The surface integrity of the machined components of the high volume fraction SiC particle reinforced Al composites (SiCp/Al) is important as it influences the performance of the part. The grinding experiments of 55% volume fraction SiC particles reinforced Al composite with and without ultrasonic-assisted were performed. The grinding forces were tested, on which the effects of the grinding parameters were analyzed. The surface topography of SiCp/Al after ultrasonic assisted grinding were observed, based on which the material removal mode was discussed.
Abstract: Based on nonlocal theory, The effects of ultrasonic frequencies on the grinding force and nonlocal decay rate are obtained through the experimental study of material properties under ultrasonic vibration grinding test. The results of experiments showed that grinding force is attenuated in the ultrasonic vibration frequency ranges and this attenuation phenomenon becomes more and more evident by the increase of the ultrasonic frequencies. Through analysis of the grinding surface morphology and phase structure, it showed that ultrasonic vibration greatly reduces the average grinding force, and the surface quality are improved, and that it is much easier to achieve ductile-mode machining under ultrasonic vibration. The results of experiments are in accordance with the analysis of nonlocal theory.
Abstract: In this paper, the principle of ultrasonic assisted grinding is introduced. Experiments have been done to reveal the effect of different parameters(including feed rate, spindle speed, grinding depth, vibration amplitude on surface roughness of K9 glass both in ultrasonic assisted grinding and conventional grinding. The experiment results show that in face grinding process, the surface roughness of ultrasonic assisted grinding is worse than that of conventional grinding.
Abstract: During dry grinding of titanium alloy, workpiece burn and chips adhesion phenomenon always takes place, which influences the surface quality of the machined components. In this paper, the solid lubricants, composed of graphite and polyvinyl butyral, are covered on the brazed cubic boron nitride (cBN) mounted wheels using the ultrasonic vibration method. Test of grinding of titanium alloy Ti6Al4V is carried out with the above tools. Comparative dry grinding tests are carried out to reveal the performance this new-type abrasive tools. Experimental study shows that the grinding temperature with the cBN grinding mounted wheels covered by graphite is lower than that of non-lubricant-covered wheels; the grinding surface with the cBN mounted wheels covered by graphite is remarkably improved with a roughness Ra lower than 1.5 μm. And graphite lubricant participates in grinding operation constantly.
Abstract: Medical titanium plates with smooth surface will be long-standing in body under the condition of free state when it used for bone fixation. To solve this problem, function-surface titanium plates with a certain roughness and shape must be grinded. So ceramic CBN abrasion wheel is used to grind titanium alloy in CNC machining tool and the status of force, heat and vibration in the grinding process will be monitored in the same time. The surface morphology which can meet the growth of tissue could be obtained in a certain technological conditions by observing the grinded surface with super depth of field microscopy devices.
Abstract: The carrying of Liquid hybrid bearing for ultra-high speed grinding is complex. The oil film temperature distribution in different input state is obtained through CFD analysis by FLUENT. On this basis, the temperature characteristics laws of the oil film with the input parameters change were obtained. Analysis shows that the relationships of oil film temperature with spindle speed and eccentricity are directly proportional and super linear, the relationship of oil film temperature with oil supply pressure is inverse ratio and the relationship with oil supply temperature is approximation directly proportional to the linear. Finally the significant of the various input parameters are analyzed through the orthogonal test. The results show that the effect of spindle speed is most significantly.