Papers by Keyword: Material Removal Mode

Abstract: Fixed abrasive technology which has many advantages is one of the future machining directions. Free and fixed abrasive lapping of BK7 glass was investigated and different material removal modes and surface damage categories by lapping were discussed. The results show that material removal rate is larger for free abrasive lapping than that of fixed abrasive lapping with four abrasive sizes and decreases with diamond size decreasing in two lapping processes. Surface quality is better for fixed abrasive lapping than that of free abrasive lapping at the same diamond size and gets better with the decreasing of diamond size. Fixed abrasive lapping can achieve simultaneously high MRR and good surface quality.

Abstract: The machining characteristics of cemented carbide YG8 under high speed grinding conditions are reported in this paper. The experimental investigation focused on the grinding force, surface roughness and surface characteristics influenced by various wheel speeds, feed rates and depths of cut. Surface roughness was slightly improved by increasing of wheel speed, and the increase in h_max generated bigger grinding force and decreased specific energy, which could be explained by material removal mode and SEM micrographs of surface. The results revealed that high machining efficiency was achieved and relatively good surface roughness was obtained simultaneously.

Abstract: Based on the single diamond grit scratching and normal grinding assisted with ELID (Electrolytic in Process Dressing), the surface/subsurface integrity of machined spectrosil 2000 and BK7 glasses under various material removal modes have been investigated. In Single diamond grit scratching tests, the scratching traces display four kinds of scratch characteristics according to different material removal modes. In the diamond normal grinding, the surface/subsurface integrity analysis shows BK7 glass has a better machinability than that of spectrosil 2000. Moreover, with the increasing a_e(depth of cut), these two kinds of glasses had the opposite variation trends about the Ra values and the force ratio, which is attributed to various material removal modes. While contrasting these two kinds of optical glasses ground under the same a_e parameters, the smaller grinding force and grinding force ratio (F_n/F_t), as well as the more stable force curves correspond to a better surface quality.

Abstract: The main function of the wheel side is to remove the material and the main function of the wheel edge is to finish the workpiece in quick-point grinding process. So the grinding layer model of conventional cylindrical grinding process is not fit for quick-point grinding process anymore. Based on the technical characters and the principle of the process, a new side contact layer model and the formulas to calculate the contact layer parameters are presented. It is basement to study the mechanism of materials removal and wheel wear in quick-point grinding process.

Abstract: In order to improve the application of neutron scattering technique, a new neutron optical device, which optical system consists of an array of several ten neutron Fresnel lenses, is designed by the researcher engaging in the study of neutron optics. Neutron Fresnel lenses for this new device have the same symmetric concave form. Its center is a spherical surface and the other surfaces are conic section. MgF2 single crystal glass is selected as the material for making neutron Fresnel lens because of its high transparence. Considering the form complicity and the brittle properties of MgF2 material, the fabrication of neutron Fresnel lens is of very difficulty. Form ELID (electrolytic in-process dressing) grinding was used for grinding the neutron Fresnel lens in this first study. The optima of grinding conditions for #325, #1200 and #4000 cobalt bonding diamond abrasive wheels are obtained through a series of tests. The MgF2 material is removed at the ductile mode by using #4000 abrasive wheel. Thus, the neutron Fresnel lens fabricated has low roughness and high transparence. The transmission of an array of 50 pieces of neutron Fresnel lens is 92.5 percents to neutron beam with wavelength 5Å and 79.3 percents to 16Å.