Rounded diamond cutting tools are used for ultraprecision cutting widely. The lapping qualities of the nose arc play a
quite important role on the achieved accuracy of the machined surface. Therefore, it is urgent to solve the high-precision
lapping problem of the nose arc. Firstly, based on the periodic bond chain (PBC) model, ratio model of material removal
rate is proposed for tool nose arc, in which the {100} crystal plane is oriented as the rake face. And then, the optimal
lapping direction is obtained for the nose arc of diamond cutting tools. More over, two lapping methods are proposed for
tool nose arc according to the formula of material removal amount. The first is the lapping under variable pressure; the
other is the lapping under variable time. After that, a new type lapping machine is designed by top-down method of
Pro/Engineering. According to the requirements of the tools, a novel measuring method based on atomic force microscope (AFM) is put forward for nose roundness. A complete system is built for lapping of nature diamond cutting tools' nose arc.
In order to satisfy the machining of high precision components, much higher accuracies have been put forward for diamond cutting tools. From the viewpoints of fabrication and utilization of rounded diamond cutting tools, the material removal mechanism of lapped diamond surface layer is studied by lapping experiments. And also, the crucial processes for tool fabrication and re-lapping are analyzed and discussed. Moreover, the working state of lapping equipment affecting tool lapping quality is lucubrated. At the same time, the representative qualifications of rounded diamond cutting tools are defined and their assessment methods are proposed, respectively. Finally, in terms of the relationship of the removal mechanism and tool lapping quality, the lapping parameters are optimized for the fabrication of high precision diamond cutting tools. The results indicate the sharpness can be reduced to 30nm.
There has been much interest in the field of laser radar (ladar) owing to its high-resolution three-dimensional imagery. However, the coherent ladar images are affected badly by speckle, which is a multiplicative noise and has the statistical features of the negative exponential density. In the paper, the morphological filter based on the parametric edge detection is introduced in detail. Then, this detector and the ratio edge detector are compared with the conventional LOG (Laplacian of Gaussian) operator and Canny operator. At last, the edge detection results for coherent laser radar image are obtained. The experimental results show that the morphological filter based on parametric edge detection and the ratio edge detector are better than other algorithms for coherent ladar image, and the morphological filter based on the parametric edge detection is the best algorithm in this paper.
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