Papers by Keyword: Grinding Wheel

Abstract: The chip formation mechanisms during grinding are not yet fully understood. The abrupt interruption of the grinding process with a quick stop device is a suitable method to analyze the chip formation mechanisms during grinding. However, there is no device available that enables a reproducible interruption at cutting speeds above vc = 5 m/s. Therefore a new method for the interruption of face grinding processes in order to analyze the chip formation mechanisms is presented in this paper. A quick stop device is designed and constructed based on the advantages and disadvantages of former approaches of other researchers. Grinding experiments with different rotational speeds confirm the potential of this new device. Interruptions of the grinding process at cutting speeds of vc = 5 m/s, 15 m/s, 25 m/s and 35 m/s are successfully accomplished. A detailed analysis of the contact zone with the help of SEM pictures impressively shows the interaction of hundreds of cutting edges along the contact zone.

Abstract: Cylindrical parts with a protrusion are expected to be used in the components of consumer electronics and automotive products. The machining efficiency of these parts is very low, making them difficult to be mass-produced. The aim of our present work is to develop a highly accurate and highly efficient grinding process for a cylindrical surface with a protrusion. This paper describes the results of experiments using a straight cup-shaped grinding wheel. The following conclusions can be drawn. (1) To prevent uneven wear of the grinding wheel, an oscillation operation is necessary during the grinding process. (2) By employing the straight cup-shaped grinding wheel, the grinding process is realized with the aim of achieving the following: high machining accuracy, roundness below 3 μm, straightness below 2 μm, and surface roughness below 2 μmRzjis.

Abstract: In grinding process, the grinding wheel profiles are copied to workpiece surface. Therefore, the finished workpiece surface can be estimated by the grinding wheel surfaces. In this paper, new measuring method of the distribution of cutting edge in grinding wheel surface by two AE sensors is proposed. From experimental results, it is confirmed that the distribution of cutting edges in wheel surface can be measured easily by the proposed method compared to another measuring method.

Abstract: The work described in this paper pertains to the identification of some features of micro- and macroprofile formation of surfaces to be machined with flat face grinding, with inclination of the spindle axis. The question of the formation of machined surface profile at through-feed grinding and multiple-pass scheme are considered by using computer-aided simulations in COMPASS environment. More specifically, for flat face through-feed grinding, a generalized empirical equation exhibiting the dependency of concavity from the outer diameter of the face grinding wheel, the spindle axis inclination angle and the width of the surface of the workpiece is acquired. Furthermore, based on the maximum allowable value of flatness deviation and with pre-determined grinding wheel diameter and workpiece width, it is possible to identify the maximum inclination angle at which concavity falls within acceptable limits. For the case of multiple pass flat face grinding, the role of factors such as inclination angle of spindle axis, cross-feed and diameter of the grinding wheel on the height of residual ridges on the surface of the parts is determined through the proposal of an empirical equation. With the aforementioned equations the machinist may reasonably prescribe machining conditions in practice. The conducted research contributes to the expansion of ideas regarding technological possibilities of improvement of flat face grinding.

Abstract: Diamond grinding wheel is used in high precision grinding process, when work piece has a very high hardness. For a specific grinding interval, the wheel must be properly dressed, in order to remove swarf, sharpen the worn diamond grits, open up new diamond protrusions, and recondition the bond material. Dressing of diamond grinding wheel by alumina dressing tool has been simulated in a pin-on-disk machine in the research. Sharpening of the wheel is indicated by the increase of its roughness value, and surface microstructure with protruding sharp diamond grits. It was found that increasing of sliding distant from 100 to 500 m will increase the roughness of the wheel. The increase of contact load from 10 to 20 N will also increase roughness of the wheel, and the severity of wheel wear, indicated by high values of friction coefficient. A proper dressing of this nickel bonded SD1200 diamond wheel is by sliding against alumina dressing tool for at least 300 m under 10 N load. Sliding velocity has minimal effect to the results. A too large sliding distant and load will cause severe damage to wheel surface, and severe wheel wear, indicated by its large mass loss.

Abstract: There is the grade as one of the selection criteria of a grinding wheel like WA whetstone or GC whetstone. The grade of grinding wheel is defined as an index which shows the strength of connection of a grain and a grain, and is usually estimated by bending strength. There are many papers about the relationship between the grade of a grinding wheel and the grinding performance. And, the relationship between the grade of a grinding wheel and the grinding performance is almost clear. Also, the relationship between mechanical properties of a grinding wheel and the grade is also clear. On the other hand, since the grain layer of a super abrasive grinding wheel is thin, it is difficult to apply the conventional evaluation test of the grade. And, the evaluation method of the grade which can be adapted the super abrasive grinding wheel is not established. In addition, since the grade of a super abrasive grinding wheel is a manufacture manufacturer's original standard, there is a minute difference by manufacturer. The super abrasive grinding wheel as well as the grinding wheel is conjectured that the grade influences the grinding performance. Namely, it is important to relate the grade and the mechanical properties of a grain layer. However, researches which relate the grade, the grinding performance and the mechanical properties of a super abrasive grinding wheel are not done so far. Therefore, this study examined the relationship between the mechanical properties of a grain layer of a super abrasive grinding wheel and the grade, the grinding performance. The final objective of this study is to evaluate the grinding performance from mechanical properties of a grain layer of a super abrasive grinding wheel. The purpose of this report is to clarify relationship between the grade and the grinding force in a resinoid bond diamond wheel. The specific experiment procedure is as follows. When carrying out surface grinding of the diamond sticks using a grinding wheel, the relationship of the grade and the grinding force was clarified. And based on the knowledge acquired in this experiment, relationship between the grade of a super abrasive grinding wheel and the grinding force was considered. As the results, it confirmed that the grade of a resinoid bond diamond wheel could be evaluated by the grinding force.

Abstract: This paper presents a general mathematical model for NC-machining an APT-LIKE rotating cutter. The design model of cutting-edge and helical groove are also developed by using the principles of differential geometry and kinematics. The analytical solution for the resolution profile of helical groove has also been developed. The results of numerical experiment indicate that the proposed systematic design method by using 2-axis NC machine setup are feasible and reliable.

Abstract: We explored the effect of supplying coolant from the inner side of a grinding wheel on the residual stress caused by grinding. Effect of depth of cut on grinding temperature and residual stress was also studied. Results clarified that grinding with an internal coolant supply induced a larger compressive residual stress compared to a conventional external grinding fluid supply when depth of cut was large. In addition, grinding temperature in the internal grinding fluid supply was lower than in the external grinding fluid supply, as measured by infrared thermograph camera. Findings suggested that large compressive residual stress was obtained in the case of the coolant supplied from the inner side of the grinding wheel because temperature was lower than external coolant supply.

Abstract: The surface of the grinding wheel and the conditions under which it is prepared has a profound influence upon the grinding performance as characterised by the grinding forces, power consumption, cutting zone temperature and component surface finish. Only by having a clear understanding of the wheel topography can the interaction of the grinding wheel surface with the workpiece be fully understood. Two dimensional measurements or profilometry, while being a relatively quick measurement to perform, suffers from information quality issues due to the subjectiveness of the profile location as well as questions regarding how representative a profile is of a three-dimensional real surface. While profilometric measurement has long been standardised in the form of various international standards, topographic standards have only recently been agreed upon and formalised as ISO 25178. In this paper a comprehensive approach to wheel topographic characterisation will be undertaken. Factors such as measurement strategy, filtering, active grain identification as well as the fidelity of surface replication will be considered. The paper will propose a recommended measurement strategy and surface parameter set deemed sufficient to provide a comprehensive understanding of the grinding wheel topography.

Abstract: The surface of a grinding wheel dressed by a diamond rotary dresser was generated by computer-aided simulation for the case of multipass dressing on the assumption that the grinding wheel is a homogeneous solid body and the dressing trajectories of the diamond grits are perfectly copied on the grinding wheel surface. The dressing process was visualized as a contour map of the dressed surface profile and the effects of the dressing strategy, i.e., down-cut dressing or up-cut dressing, on the grinding wheel removal process were investigated. It was found that the diamond grits remain the residual depth of cut on the surface of the grinding wheel, resulting in an actual depth of cut larger than that given by the rotary dresser.