Papers by Keyword: Diamond Cutting

Abstract: This paper describes the cutting characteristics of lithium niobate, which is used for surface acoustic wave type micropumps, regarding the formation of micro grooves by direct cutting. Since lithium niobate is a brittle material with a strong crystal orientation dependency, significant differences were observed in the characteristics of the finished surface according to different directions of cutting. The ductile mode cutting of lithium niobate was found to be feasible with cutting depths of approx. 5 μm or less. Also, results of the study show the feasibility of the formation of minute grooves through the cutting of lithium niobate, using milling with an end mill.

Abstract: In diamond cutting of optical glasses, the magnitude of critical depth of cut for brittle-ductile transition is an important factor affecting the machinability of the work material in terms of production rate and surface quality. In this work, scratching tests with increasing depths of cut were conducted on glass BK7 to evaluate the influence of the cutting fluid properties on the critical depth of cut. Boric acid solutions of different concentrations were selected as cutting fluids in the tests. The resulting scratches were examined utilizing a white light interferometer and the values of the critical depth of cut were determined based on the observations of the micro-morphology of the scratch surfaces produced. Experimental results indicated that compared with the process without cutting fluid action, the critical depth of cut in diamond cutting of glass BK7 can be increased by using boric acid solution as the cutting fluid.

Abstract: Tool wear in diamond cutting sinusoidal mircostructured surfaces may be quite different from that in conventional diamond turning as the sharp point tip tool is used and the depth of cut changes cyclically along the profile of the cutting surfaces. In present paper, the diamond tool geometry requirements for cutting sinusoidal microstructured surfaces were analyzed. A series of controlled cutting tests of LY12 were executed on a 2-aixs bench type ultra-precision turning machine which equipped a fast tool servo (FTS). Tool wear patterns were investigated with varied feed speed in diamond cutting sinusoidal microstructured surfaces. The scanning electron microscope (SEM) examination results of tool wear showed that the visible wear was occurred after a short cutting distance. The gradual wear around tool tip and along cutting edges was predominant wear pattern with a low feed speed. The catastrophic fracture wear at tool tip was happened with a high feed speed and the wear of sharp point tip of tool was more serious than that of cutting edges of tool.

Abstract: Glass possesses poor machinability in diamond cutting due to its high hardness and high brittleness. In order to investigate the effect of cutting fluids on the machinability of glass, this paper first conducted soda-lime indentation experiment, and then examined the resulting indentation by optical microscope. Based on this, turning tests were carried out to evaluate the influence of the cutting fluid properties on the machinability of glass. Boric acid solutions were selected as cutting fluids in the tests. The surface processing quality of soda-lime was assessed based on the observations of the micro- morphology of the turned surfaces utilizing AFM. Experimental results indicated that compared with the process without cutting fluid action, the machinability of glass soda-lime can be improved by using boric acid solution as the cutting fluid.

Abstract: Air bearings had been widely used in ultra-precision machine tools. In order to suppress the micro-vibration caused by air bearing, an effective way is keeping the air flow in laminar state. Porous bearing to control the micro-vibration was proposed in this paper, and the related experiments show that it can meet the requirement of decreasing the micro-vibration to less than 1nm, and the surface of diamond surface can be improved.

Abstract: Optical glass is one of the most difficult-to-cut brittle materials due to its high brittleness and high hardness. In this work, an experimental study was conducted to diamond-cut glass SF6 in ductile mode. Nano-indentation analysis was performed for understanding the material deformation behavior in practical cutting process. The effect of process conditions, i.e. conventional turning and ultrasonic vibration assisted cutting, on the tool wear and surface quality was discussed based on the observations of the tool wear zone microstructure and the machined surface topography. The investigation presents the feasibility of achieving optical quality surfaces on glass with the application of ultrasonic vibration cutting technology. The tool life and surface finish were improved significantly by applying ultrasonic vibration to the cutting tool.