Papers by Keyword: High Speed Lapping

Abstract: A new method is proposed that high speed lapping aspheric surface workpiece using lapping tool by means of bending because there processing difficult, In this study, the principle of high speed lapping has been presented, the mathematical model for the lapping tool has been established, and the equidistance curve error of the lapping tool has been analyzed. The results of the experiment indicate that the forming precision of the lapping tool is high using this method, the surface precision of the workpiece reaches micron grade, furthermore, the aspheric surface workpiece can been machined using this method in lapping, and that it can meet the need of medium precision of machining the aspheric surface workpiece. The experiment result indicates that the the lapping tool shape precision is high, the lapping error of the workpiece is 0.0108mm, and lapping efficiency is high and the cost is low. This aspheric lapping method has incomparable superiority of other processing methods.

Abstract: This paper proposes a new method of controlling abrasives density distribution on the machining surface of a lapping tool making full use of controllability of abrasives density distribution in solid abrasive lapping, based on the present actual problems in solid abrasive lapping blind holes in manufacturing process. This method makes the abrasives density distribution on the lapping tool surface fit the wear intensity distribution of lapping tool, which makes the lapping tool wear uniformly in this manufacturing process, does not lose its original surface accuracy, ensures shape accuracy of the machined holes of the workpiece, also avoids the trouble of dressing lapping tools, reduces auxiliary machining time, improves machining efficiencies, reduces the consumption of abrasives and reduces machining costs of the manufacturing process.

Abstract: The surface roughness of machined surface is one of the important indicators to evaluate the workpiece machining quality. In order to clarify the change law of surface roughness in ultrasonic aided high-speed lapping with solid diamond abrasive, a series of ultrasonic and conventional lapping experiments of different engineering ceramics, such as Al2O3, ZrO2 and ZTA, were carried out on precision lathe with self-made high-speed ultrasonic lapping device. The research results show that the value of surface roughness in ultrasonic aided lapping is lower than that in conventional lapping. With the assistance of ultrasonic vibration, the surface quality can be improved obviously. In ultrasonic aided lapping, there is an optimum lapping pressure from which a better surface roughness value can be obtained. Because of different physical and mechanical properties, material removal mechanisms of the three kinds of engineering ceramics present different characteristics, which lead to the different surface roughness even though under the same lapping conditions. The research of the paper is helpful to optimize lapping technique and improve the surface quality.

Abstract: Because of its high machining efficiency and good machining quality, ultrasonic aided high-speed lapping with solid abrasive is regarded as a good method of cylindrical machining for engineering ceramics. Compared with conventional lapping, ultrasonic aided high speed lapping has unique surface topography distribution characteristics for the difference of the surface formation mechanism and material removal mechanism. In the paper, the surface topography characteristics of engineering ceramics in different lapping mode were researched. Research results show that the lapped surfaces with and without ultrasonic assistance present different surface topography characteristics. Under the same lapping mode, the lapped surface topography is distinctly different for different ceramics. With the assistance of ultrasonic vibration, more ductile material removal can be obtained and the surface quality can be improved correspondingly.

Abstract: Considering the shock between the press head and press disk in high speed lapping is more serious, this paper proposes a new method to reduce this shock. By this method a hole is machined for air passing on the press head axis. The topper of the hole is connecting with a pressure air resource. Thus an air cushion between the press head bottom and press disk on the workpiece is produced. With the distance between them reducing gradually, the damping of air cushion on the press head increases gradually. This makes speed of the press head approaching the workpiece decrease gradually and until reach zero. The pressure of the press head acts on the press disk increases gradually from zero to working pressure, which can reduce the shock between the press head and workpiece effectively, prevent weak workpiece from destroying in lapping and improve machining accuracy and quality. This method possess the advantages of easy to carry out, simple to operate and convenient to apply.

Abstract: An experimental investigation is carried out to machine SiC ceramic material through method of high speed plane lapping with fixed abrasive. The results show that the material removal mechanism and the surface roughness are chiefly related to the granularity of abrasive and the lapping pressure for the brittle materials such as SiC ceramic. It is easily realized to machine SiC ceramic material in ductile mode with a high efficiency and a low cost using W3.5 grit under a lapping pressure of 0.1MPa and then a smooth surface with surface roughness of Ra 2.4nm can be achieved.

Abstract: This paper discusses a new lapping ellipsoid method, which combines high-speed lapping technology with solid abrasives and lapping tool bending method. In this method, a bending moment is acted on lapping tool with solid abrasives, which makes it bend to form a shape on its working surface, which is the same as generant of workpiece shape. This kind tool is used in forming lapping on a high speed lapping machine. With the development of science and technology, the requirements for optics systems become higher and higher, e.g. good quality of imaging, little loss light energy, small size and light weight etc. It is difficult to reach above requirements by using traditional sphere lens/mirrors in optics systems. Aspheric optics elements can be used to solve these problems. In optics systems, by using aspheric optics elements, the number of optics elements can be reduced, the system structure can be simplified, the weight and size of the system can be reduced, light energy loss can be reduced too, imaging errors can be avoided and imaging quality can be improved. Ellipsoid is a kind of surface being used widely within all kinds of aspheric surfaces. The main purpose of this paper is to introduce a method of lapping this kind of surface at high speed.