Papers by Keyword: Polishing

Abstract: The waste generated in the process of polishing of ceramic materials represents a challenge for the ceramic industries, because it is necessary conciliate environmental protection to expenses with disposal and proper packaging. The study of the reuse of this material in the production cycle becomes a necessary alternative to solve the industrial problem. The replacement of the abrasive agent is a viable option in order to avoid the presence of silicon carbide and the residue therefore enabling the direct incorporation of the residue in the porcelain production. If the atomized paste contains silicon carbide when the material is burned occurred the formation of porosity and cracks in the piece. This work aims to study new alternatives of abrasive agents and evaluate the efficiency of polishing generated by new tools. To evaluate the performance of the abrasive tests were conducted simulating the polishing step. The study is based on the computational processing of the image generated by optical micrographs. From this, it will be possible find the best abrasives for polishing ceramic material.

Abstract: This study examines the feasibility of using high-porosity and conductive bamboo charcoal in electrophoretic deposition (EPD)-assisted polishing of silicon wafers and explored the influence of various parameters on surface roughness. EPD-assisted polishing with bamboo charcoal offers an alternative to the lapping process prior to CMP. According to the results, the best parameter combination obtained under the current experimental setting is machining time, 12 min; rotational speed of platen, 75 rpm; and voltage, 6V. EPD indeed contributes to more effective and efficient polishing, with better surface quality attained within a shorter machining time.

Abstract: Grinding technology is used in this study to overcome the hard machining of ceramic with hard and brittle characteristics. The grinding machine with diamond grain size 25 and 5 , spindles speed 1720 rpm and 3450 rpm are applied. Combining the unintentional roll clamp and the grinding machine, ceramic rods can be ground to the desired size.In the research, surface profilometer is applied to measure the rod surface roughness of processing results under different conditions. The results show that the grinding wheel with finer particle, the roughness of the ground ceramic rod will be better. While the rotation speed of grinding wheel is increased, the surface roughness will have the same trend.

Abstract: A kind of elastic coated abrasives used for polishing large mould surface, such as automobile panel mould, is investigated in this research. Many polishing experiments were finished by using elastic coated abrasives in order to study the effects of grit and workpiece material on surface roughness and machining efficiency. It is concluded that surface roughness is minimum and polishing efficiency is the highest when using 120^# abrasives at the same condition, surface roughness is the lowest and polishing efficiency is the highest for AISI 1045 steel in three materials. The difficulty of material removal is different if the textures prior to polishing are different in workpiece surface. Surface texture prior to polishing has effects on surface roughness and polishing efficiency. The research results provide foundation for process planning to achieve good surface roughness and high efficiency in the future research.

Abstract: Polishing is a secondary process in machining. The application of polishing process is crucial to obtained final appearance of a product. This study addresses parameter analysis on flat and dry polishing to determine the most influence parameter which effect surface roughness. For this purpose, Design of Experiment (DOE) is used as a methodology in the analysis. The polishing process is conducted on Comau robotic cell and the combination of grit size, polishing time and polishing force are subjected on the material by using pneumatic polishing tool. Two-level factorial experiment design is conducted and result is interpreted by using statistical software. From the result it is shown that grit size and polishing time give the main effect on surface roughness. However for 2-way interaction effect, polishing time and polishing force contribute significantly on surface roughness. This suggested that for flat and dry polishing, consideration on these parameters is an essential aspect in order to achieve a good surface finished.

Abstract: This paper aims at studying the effect of polishing parameters on surface roughness by using the cloth wheel polishing process. Stainless steel was used as a specimen in this study. The investigation firstly accounted for the comparison between two polishing compounds, and the best one was used to be applied in a set of experiment. The effect of spindle speed, current and polishing time on the surface roughness of stainless steel was examined, and the results showed that polishing time and current played the significant role in degree of roughness. The optimum condition under the range of parameters considered in this work was determined, whose surface roughness was about 0.0466 μm.

Abstract: A polishing process is generally used for improving work surface quality through the abrasive machining scheme. In this study, a stainless steel cookware was polished by using a sisal wheel and its surface roughness was examined. A comparison of three different sisal wheels was initially made to evaluate their performance in terms of capability to achieve the required surface finish against the processing time. The polishing force, time and velocity were the three main parameters, taken into consideration in this study. The optimum condition of 61 m/s, 15 seconds and 65 N for polishing velocity, time and force was suggested, respectively. After implementing the optimum condition and comparing to the current setting, the processing time can be reduced by half.

Abstract: In this work, optical K9 glass surface has been flattened by nanoparticle colloid jet machining, which is an ultra-smooth surface processing technique utilizing surface chemical effect between work surface atoms and nanoparticles in alkaline colloid to remove the uppermost surface atoms. The surface removal process of nanoparticle colloid jet machining has been investigated through K9 glass polish experiments. And the characterizations of ultra-smooth K9 glass surface polished by nanoparticle colloid jet machining have also been studied in this paper. Surface profiler and atomic force microscopy (AFM) are used to observe the surface microscopic morphological characteristics of K9 glass sample before and after polishing by nanoparticle colloid jet machining. The measurement results of processed surface prove that the primary scratches on the original surface have been completely wiped off by nanoparticle colloid jet machining and the roughness of the K9 glass surface has been improved to be less than 1 nm (Rq). Autocovariance (ACF) is investigated along a cross section of the K9 glass surface to determine the dominant spatial frequencies. The ACF curves show that the surface morphology of K9 glass processed by nanoparticle colloid jet machining is completely different from the preprocessed surface. The final K9 glass surface has been flattened by nanoparticle colloid jet machining. The microscopic morphological profile of the final K9 glass surface becomes increasingly smooth and eventually close to a flat state.

Abstract: The production of 150 mm-diameter SiC epitaxial wafers is the key to the spread of SiC power devices. We have developed production technology of the epitaxial growth for 4° off Carbon face (C-face) 4H-SiC epitaxial layers on 150 mm diameter substrates. Several growth parameters and hardware were optimized to obtain high uniformity wafers. We have succeeded in fabricating high quality C-face wafers with smooth surface and high uniformity.

Abstract: A novel abrasive-free polishing method called catalyst-referred etching (CARE) has been developed. CARE can be used to chemically planarize a silicon carbide (SiC) surface with an etching agent activated by a catalyst. Platinum (Pt) and hydrofluoric (HF) acid are used as the catalyst and etchant, respectively. CARE can produce an atomically flat and crystallographically highly ordered surface of 4HSiC (0001) with a root-mean-square roughness of less than 0.1 nm regardless of the cut-off angle. However, industrial use of CARE is difficult because of HF acid usage. In this study, pure water was investigated as an alternative etchant to HF acid. We examined CARE using pure water by applying it to the planarization of a 4HSiC substrate and observed a feasible performance. The removal mechanism is considered to be the dissociative adsorption of water molecules to the SiC bonds of the topmost Si atom, namely the hydrolysis of the back bond, and the catalysis of Pt is considered to enhance the reaction. CARE with pure water is expected to represent a breakthrough method for surface processing of SiC, and will be widely applied in industrial processes such as planarization after high temperature processing in device fabrication.