High Speed Lapping Research Articles

Grinding Hyperboloid Part by Bending Method

In view of the machining difficult problem of hyperboloid, a new method is presented that high speed lapping hyperboloid parts using the bended lapping tool, and the principle of high speed lapping by the bending method is discussed. The mathematical model of bended lapping tool has been established using mechanics and higher mathematics, and the expression of width function of lapping tool is deduced. Analysis of the calculating example indicated that this method is possible to design the needed lapping tool. The bending experiment of lapping tool has confirmed the feasibility using this method, the biggest error of face shape was 1.0038μm, the face shape precision can satisfy the majority part request.

Lapping Aspheric Workpiece Using Bending Method

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.

Research on Expert System of High-Speed Plane Lapping Machine with NC Based on Network Knowledge Acquisition

This paper focuses on integrated development of high-speed lapping technology, expert system and network technology. Data mining objects are high-speed lapping experiments and previous experiences, in the plane high-speed lapping processing; the network technology is embedded in NC machine, through inputting the processing requirements of the work piece surface roughness, and the network expert system reasons out the appropriate processing parameters to insure precise high speed lapping.

S133024 枚葉式ラップ盤による工作物位置が加工特性に及ぼす影響

The lapping is one of the processing to remove waviness and roughness of the workpiece. Therefore, this processing is used to process of the silicon wafers. In this lapping process, the four-way lapping machine is generally using at the wafer processing of semiconductor chips. However, the silicon wafers have been changed to the large sized wafers to decrease the wafer cost, year by year. According to large size of wafers, the four-way lapping machine becomes large, the deterioration of wafer accuracy by deflection of heavy machine parts and the transportation of lapping machine have been a problem. In this study, it is an aim to study the possibility of high speed lapping using trial manufactured single-wafer lapping machine by authors. This lapping system is able to lap the single wafer using divided lapping plate. In this study, the relation between the position of workpiece and the accuracy of wafers was studied. At the results, it is clear that the surface waviness of cp200 wafer improves to 2um.

Experimental Study on the Characteristics of Surface Roughness in Ultrasonic Aided High-Speed Lapping of Engineering Ceramics

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.

Surface Topography Characteristics in Ultrasonic Aided High Speed Lapping of Engineering Ceramics

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.

Influences of Ultrasonic Assistance in High Speed Lapping of Nano ZTA Engineering Ceramic on the Surface Machining Quality

Ultrasonic aided high speed lapping with solid abrasive material was put forward aimed at the precision finishing of nano ZTA engineering ceramic. Through theoretical analysis and contrast lapping experiments, the influences of ultrasonic assistance on the surface machining quality were clarified. Research results show that the maximum undeformed chip thickness in ultrasonic aided lapping is smaller than that in conventional lapping under the same conditions; ultrasonic assistance is beneficial to enlarging the range of ductile lapping regime and improving the surface quality of nano ZTA ceramic; with the application of ultrasonic vibration, smaller surface roughness and more regular surface profile can be obtained.

A New Method of Reducing Shock between Press Head and Press Disk in High Speed Lapping

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.

High Speed Lapping of SiC Ceramic Material with Fixed Abrasive

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.

Nanometer lapping technology at high speed

In floating lapping with solid abrasives, the workpiece is taken as an isolated body. The forces that act on it are analyzed. A differential equation about the forces that act on it is set up, so the forces that act on it and its motion rule are received. Combining it with known lapping tool motion, the relative motion rule between the lapping tool and workpiece is determined too. According to the relative motion, the distribution of abrasives density is designed reasonably, which makes the lapping tool wear uniformly, which, in turn, avoids redressing the lapping tool, saves abra-sives, and increases machining accuracy. Combining it with advantages in high speed lapping with solid abrasives, the low cost, high efficiency nanometer lapping at high speed is realized.

High Speed Lapping Ellipsoid by Means of a Lapping Tool Bending Method

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.