Advanced Materials Research Vols. 126-128

Abstract: Most existing models for abrasive jet machining (AJM) are based on erosion models for either ductile or brittle materials. This classification imposes some limitations, because most materials are neither absolutely ductile nor absolutely brittle, but lay within the continuous spectrum between those two idealizations. This work reports recent progress in the modeling of erosion processes for real materials, and discusses the implications of a new model in estimating the performance of AJM. The new model is more capable in explaining the effects of jet velocity, abrasive particle size, and various material properties on the efficiency of the cutting process.

Abstract: We compared the characteristics and polishing effect of abrasive suspension slurry jets with and without high polymer added. Results show that adding high polymer to the slurry jet leads to more concentrated jet beam and, consequently, surface roughness in the jet polished region is approximately equal and the interface between polished and unpolished regions is narrowed. We also examined the surface forming process polishing with slurry jet added with high polymer, and then proposed a polishing model of the process.

Abstract: In the lapping of magnetic heads and other electronic components composed of multiple materials, differences in the processing characteristics of the composite materials result in “residual steps” forming on the surface at composite interfaces. Residual step heights have been reduced to as little as a few nanometers. We investigated using fine abrasives in fixed abrasive lapping for this purpose, which requires highly secure, high-density embedding of the abrasives on the lapping plate. To this end, we modeled the abrasive embedding process and investigated the relationship between the mechanical properties of the lapping plate and the retention of the abrasive, to determine the direction of further research and development. The results of this investigation revealed a correlation between the work hardening in the plate and the resulting abrasive density and cutting edge height. The investigation also showed that it is possible to suppress the reduction in lapping rate that occurs during use by increasing the work hardening coefficient of the plate.

Abstract: The paper presents an investigation of grinding material removal mechanism using finite element method. Understanding of grinding removal mechanism relies on the investigation of material removal by each individual grain. Although some analytical formulations have been developed to predict and to quantify the machining events in grinding, they do not illustrate every stage of abrasive actions. Finite element analysis provides good facility to present details of physical behaviour in grinding. In this research, material removal mechanism of grinding, namely rubbing, ploughing and cutting, is discussed with the variation friction coefficient. The major emphasis here is on the ploughing. Total force variation exerted during indention and sliding of a grain is also presented along its path.

Abstract: This paper introduces a study on a multi-objective optimization problem of abrasive blasting systems. The aim of the study is to find the optimum exchanged diameter of boron carbide nozzles. In the study, the effects of several parameters such as the maximum nozzle diameter, the nozzle wear and the cost components on the optimum initial nozzle diameter were taken into account. From the study, a regression model for determination of the optimum initial diameter of boron carbide nozzles was introduced.

Abstract: Micro abrasive air jet machining technology is being increasingly used in the fields of micro cutting. Since the aspect ratio is a major interest characteristics of kerf in micro cutting, an experimental investigation is carried out to study the effect of cutting process parameters on the aspect ratio in this study. It is found that the aspect ratio increases with an increase in air pressure, abrasive flow rate and jet incidence angle, while decreases with an increase in nozzle traverse speed. Furthermore a predictive model for aspect ratio is developed using the dimensional analysis technique. It is shown that the model predictions are in good agreement with the experimental results. The research results may be meaningful to efficiently control the aspect ratio.

Abstract: Five-axis-grinding is a process, which merges high surface quality and high shape accuracy for high precision machining of multiple curved surfaces. Until now, characteristic parameters, which describe the interaction of the grinding tool and the workpiece are not available. In the present paper models for the analytical determination of the contact condition for surface normal grinding of double curved surfaces with toric grinding wheels are introduced to evaluate and configure the machining parameters.

Abstract: Super high-speed point grinding is a good performance grinding with high surface quality due to its low force. To model point grinding forces including swivel angle formed by tilting wheel to the horizontal workpiece axis seems necessary. In this research, a point grinding force model was present, and the point grinding forces are influenced by factors such as grinding depth, wheel velocity, swivel angle as well as equivalent diameter. And then some experimental tests are carried out. It is found that the experimental data was in good agreement with theoretical model.