Papers by Keyword: Polishing

Abstract: Abrasive water jet (AWJ) technology, due to its potential advantages, is a promising machining method for precision machining brittle materials. In this research, the AlN ceramics was polished using an AWJ machining system. A considerable processing quality has been achieved and a reduction up to 62% of the surface roughness has been obtained. Effects of different process parameters on the surface roughness of the polished workpiece were analyzed. Under the current conditions of the experiments, using a lower impact angle, smaller abrasives and a lower nozzle traverse speed may be appropriate for polishing AlN ceramics.

Abstract: KDP crystal (Potassium dihydrogen phosphate single crystal) is extremely difficult to obtain flawless surface because of its soft, brittle, and hygroscopic. And a large amount of time has been spend on obtaining flawless surface with ultra-precision machining methods. In order to quickly reduce surface roughness on KDP crystal, a new micro-deliquescence polishing method with fine water mist was proposed, the polishing tool with fine water mist was designed, and the polishing experiment was carried out. The micro-deliquescence polishing with fine water mist can improve the surface quality of KDP crystal quickly, so it is an effective preprocessing before ultra-precision machining.

Abstract: The contact pressure is one of the most important parameter in the industrial polishing process of ceramic tiles. The contact pressure is asically a function of the elasticity moduli of both tile and abrasive tool, the applied load, and also the curvature of the abrasive tool. Due to the wear, this curvature decreases during the polishing process, causing an increase in the contact pressure. The purpose of this work is to research the influence of contact pressure on the evolution of gloss and roughness of the polished ceramic tiles and to improve the quality of generated surface. The variation of curvature was replaced with the direct increment of three different normal forces onto the abrasive tool. It is known from literature that for fine abrasive grits higher tool loads increase gloss gain and decrease roughness. However, there are not many works that research the whole sequence of abrasives for different loads and compare the quality of the final surface. Polishing tests on a laboratory scale CNC-Tribometer have been used to study the industrial polishing process for unglazed porcelain ceramic tiles. Tests were carried out for three different tool loads with a sequence of progressively smaller silicon carbide abrasive particles embedded in a magnesia cement matrix. Tile surface quality was evaluated by roughness and optical gloss. The removed work piece material and the used abrasive were measured with a coordinate measuring machine. The distribution of gloss and roughness of the tile was measured before and during the experiments until a saturation of gloss and roughness for each grit number was achieved, respectively. The topography of the tile was measured before and after the polishing process with particularly grit number. The used abrasives show a general trend of increasing gloss and decreasing roughness during the process. The coarse abrasives caused the major effect on surface roughness and almost no effect on gloss. In opposite finer abrasives caused the major gloss enhancement and almost no effect on surface roughness. The results show the evolution of roughness and gloss for each load as a function of abrasive grit number and polishing time, as well as the material removal rate for each grit number and load.

Abstract: The appropriate planarization layer is the foundation for realization of ion beam deposition correction polishing technology, the significant difference between ion beam deposition correction polishing technology and ordinary ion beam polishing, is using spin or methods of ion beam sputtering deposition, forming sediments which has planarization effect on the processing surface to reduce intermediate frequency error, coupled with ion beam polishing, removing the high-frequency processing error, the typical error is cut marks by single point diamond turning left on the component surface.

Abstract: Polishing, a kind of finishing process done after machining is necessary to obtain a good surface roughness as well as the form accuracy. In this paper, instead of manual polishing work, a robotic polishing system is introduced. A trajectory generator needed for generating the robot polishing path are taken from the cutter location data generated from the postprocessor of a CAD system. Using the trajectory generator, the present polishing robot doesnt need the conventional complicated teaching process. Position interpolation algorithm between two CL data is proposed, and the robot control commands can also be generated using an industrial robot Motoman sv3.

Abstract: The accelerated gas ions collide with the surface material, the atom or molecule on material surface is removed by momentum transferring. Depositing a layer low viscosity of the thin film materials on the original surface of the optical, such materials will form a layer thin film on the surface of optical element that is lower than the original. Remove the high-spatial frequencies and obtain super precision optical surface.

Abstract: Ultra-precision machining is in the forefront of advanced manufacturing technology and also will become the basis of future manufacturing technology. Ultra-precision machining already has turned into the enabling technology to success in the international competition. Some new progresses in traditional ultra-precision machining processes including processing and measuring techniques, machining equipment, and analysis methods are introduced in this paper. Components with high form accuracy and good surface roughness are widely applied to precision apparatuses. Structured surfaces can be acquired by selecting reasonable machining parameters before mechanical process. The continuous growing markets will fuel many industrial sectors by ultra precision machining. We should pay great attention to the further developments of this technology.

Abstract: The paper is mainly to research the subsurface damage depth and morphology on grinding and polishing substrates on optical materials, and analyze different subsurface damage morphologies caused by different processing technologies. The best etching solution is selected by experiments, grinding and polishing substrates are etched for proper time by divided stages. Use 120×optical microscope and scanning electronic microscope to observe subsurface damage morphology and Taylor Hobson PGI1240 to measure the etching depth to obtain the subsurface damage depth.

Abstract: The dynamic changes of the friction properties of the oxide film are characterized by the dynamic changes of the ELID grinding force. The tangential force and normal force are used to represent the friction coefficient in order to obtain the accurate real-time friction coefficient of oxide film. Therefore, the friction coefficient of various grinding wheels with different bonding agents, various grinding parameters, various grinding materials (nano- Al2O3 ceramic, nano ZrO2 ceramic and ordinary ZrO2 ceramic), and ELID grinding and ordinary grinding can be further studied. The results show that: the friction coefficient of the oxide film on the bronze-based grinding wheel is greater than that composed by iron; the friction coefficient of the oxide film decreases with the increase in grinding depth and feeding speed; the friction coefficient of the oxide film and nano-materials is smaller than that of the oxide film and ordinary materials; the transformation from γ-Fe2O3 to α-Fe2O3 in oxide film and the elastic deformation of the oxide film caused by the high-temperature of grinding may make the friction coefficient of ELID grinding greater than that of ordinary grinding, so the oxide film contains better property of friction and polishing. Therefore, excellent surface quality is easier to be obtained by it compared with the ordinary grinding technology.

Abstract: Robotics especially on polishing process has not been exploited successfully in manufacturing, despite tremendous research efforts and potential needs in industries. There is still much concern on how robots are used in industries and stumbling blocks in the deployment of technology. In this study, the techniques to alleviate difficulties in using robots and deploying advanced technologies in the real manufacturing environment will be developed. However, the mirror polishing process still depends on human expert, compared to CNC and CAD/CAM technology. On top of that, undesirable working condition exists due to dust and noise. Next, it is quite difficult to find skilled technicians where existing industrial robot (normally with repetitive accuracy of 0.1mm) not suitable for mirror polishing task requirement (10nm). This study addresses idea to develop and automate the polishing process by using robots. It applies specifically on flat steel surfaces and the image of the workpiece is captured by vision sensor. The image captured is extracted to develop ANFIS (Adaptive Neuro Fuzzy Inference System) to determine the roughness so that correct polishing parameter will be applied on the surface of the workpiece when polishing is done. ANFIS is well suited to the management of uncertainty, is introduced to address the uncertainty problem associated with surface roughness.