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Search Results: 1 - 10 of 10756 matches for " surface finishing "
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Influencia del Acabado Superficial en el Digitalizado con Sensores de Triangulación por Láser
Cuesta,Eduardo; Fernández,Pedro; álvarez,Braulio J; Blanco,David;
Información tecnológica , 2008, DOI: 10.4067/S0718-07642008000300015
Abstract: the present work deals with the measurement of the influence that surface finishing has on the accuracy and quality of the scanning performed using laser triangulation sensors. amongst the great number of parameters that influence the scanning quality, the effect of roughness is analysed. to achieve this, a procedure for constraining the variables while providing an excellent repeatability and reproducibility was proposed. this procedure has been applied to several manufacturing processes that produce parts with very different quality of surface finishing. as a result, certain correlations have been extracted that quantify the influence of the roughness on the quality of the cloud-point, the spatial distribution of the cloud-point dispersion and the optimal laser intensity for each manufacturing process.
Effect of different finishing and polishing techniques on the surface roughness of microfilled, hybrid and packable composite resins
Barbosa, Silvia Helena;Zanata, Régia Luzia;Navarro, Maria Fidela de Lima;Nunes, Osvaldo Benoni;
Brazilian Dental Journal , 2005, DOI: 10.1590/S0103-64402005000100007
Abstract: this study examined the average surface roughness (ra, μm) of 2 microfilled (durafill and perfection), 1 hybrid (filtek z250) and 2 packable composite resins (surefil and fill magic), before (baseline) and after eight different finishing and polishing treatments. the surface roughness was assessed using a profilometer. ten specimens of each composite resin were randomly subjected to one of the following finishing/polishing techniques: a - carbide burs; b - fine/extrafine diamond burs; c - sof-lex aluminum oxide discs; d - super-snap aluminum oxide discs; e - rubber polishing points + fine/extrafine polishing pastes; f - diamond burs + rubber polishing points + fine/extrafine polishing pastes; g - diamond burs + sof-lex system; h - diamond burs + super-snap system. data were analyzed using two-way anova and tukey's hsd test. significant differences (p<0.05) were detected among both the resins and the finishing/polishing techniques. for all resins, the use of diamond burs resulted in the greatest surface roughness (ra: 0.69 to 1.44 μm). the lowest ra means were obtained for the specimens treated with sof-lex discs (ra: 0.11 to 0.25 μm). the ra values of durafill were lower than those of perfection and filtek z250, and these in turn had lower ra than the packable composite resins. overall, the smoothest surfaces were obtained with the use the complete sequence of sof-lex discs. in areas that could not be reached by the aluminum oxide discs, the carbide burs and the association between rubber points and polishing pastes produced satisfactory surface smoothness for the packable and hybrid composite resins, respectively.
Difference in Surface Roughness of Ethylene-Vinyl-Acetate Sheet before and after Application of Finishing Liquid  [PDF]
Mutsumi Takahashi, Yogetsu Bando
Materials Sciences and Applications (MSA) , 2018, DOI: 10.4236/msa.2018.913071
Abstract: Surface texture of the mouthguard affects the sense of adaptation in the athlete and further affects hygiene. Therefore, finish polishing is extremely important. The aim of this study was to investigate the difference in the surface roughness after finishing polishing of ethylene-vinyl-acetate (EVA) sheets and after application of the finishing liquid, and to evaluate its effectiveness. Total of 48 specimens of EVA (3 × 3 mm) were divided into 4 groups according to polishing condition (control = unpolished; condition A = Robinson-brush; condition B = Lisko-Fine, and condition C = Mouthguard-wheel). Polishing was performed at low speed by using a straight headpiece. The rotation speeds were 5000, 4000 and 6000 rpm for condition A, B, and C, respectively. Next, a finishing liquid was applied to each specimen. For application, a cotton swab was used, and it was applied by three reciprocations. A non-contact surface shape measuring machine was used for measuring surface roughness; the measurement range is 1.65 mm and the resolution is 0.01 nm. The arithmetic average height (Sa) was measured. The differences in the surface roughness before and 15 min after the application of the finishing liquid were analyzed by two-way analysis of variance and Bonferroni’s multiple comparison tests. Surface roughness of the specimen before application became coarse in the order of control, condition C, B and A, and Sa was about 0.20, 1.98, 2.92, and 4.71 μm, respectively. The degree of reduction in roughness was about 1.0 μm or more than each polished state in conditions A and B. Condition C was not significantly different before and after application. No significant difference was observed between condition B and C after application. The results of this study showed that the surface roughness decreased due to the application of the finishing liquid when the surface roughness after finish polishing was about 2.0 μm or more.
Effect of Wood Finishing and Planing on Surface Smoothness of Finished Wood
Mehmet Budakci,Levent Gurleyen,Hamza Cinar,Suleyman Korkut
Journal of Applied Sciences , 2007,
Abstract: The effect of wood finishing and planning on surface smoothness of finished wood samples of Scots pine (Pinus sylvestris L.) eastern beech (Fagus orientalis L.) and oak (Quercus petraea L.), commonly used woods in the furniture industry in Turkey, was investigated for this study which was carried out in 2006 in the capital city of Ankara in Turkey. Two hundred and forty samples were prepared and processed by planing on the radial and tangential direction to annual rings with 2 and 4 blades. Surface smoothness of the samples was measured according to Turkish Standard (TS) 930. Following that, filling coat and topcoat of polyurethane varnish were applied to surfaces of the samples according to ASTM-D 3023. Then, samples were again subjected to measure for determining the surface smoothness. Statistical data were obtained for surface smoothness from varnished and unvarnished wood samples and it was concluded that finishing increases the surface smoothness.
Qualidade Superficial de Pe?as de Alumínio Fundidas em Molde de Areia
Rubio, Juan C. Campos;Panzera, Túlio Hallak;Nogueira, Wagner Alves;
Matéria (Rio de Janeiro) , 2006, DOI: 10.1590/S1517-70762006000200006
Abstract: the present work consists to analyze the physical and chemical characteristics of sands used to foundry and its influence in the quality of the melted pieces. five different types of sand were collected, both with the same mineral treatment. the characterization of the sand was carried out through the following laboratory tests: grain size distribution (sieving), afs clay content, water content, permeability, thermal expansion, loss on ignition, sinter point, fine contents meshes and chemical composition. the optical microscope was used in order to identify the geometry of the grains of sand. two different models were made. the first one with a spiral shape was made to investigate the flow’s capacity of the metal with respect the different characteristics of the sands. the second model which is a plate with different thickness was made to investigate the quality of the surface finishing of the melted pieces. the metal used in the foundry process was the aluminum. it was observed a significant correlation between the laboratory and technological results, which means that it is possible to preview the quality of melted pieces from the characteristics of the sand grains.
Polishing methods of an alumina-reinforced feldspar ceramic
Bottino, Marco Cícero;Valandro, Luiz Felipe;Kantorski, Karla Zanini;Bressiani, José Carlos;Bottino, Marco Antonio;
Brazilian Dental Journal , 2006, DOI: 10.1590/S0103-64402006000400004
Abstract: the purpose of this study was to test the hypothesis that mechanical polishing methods of ceramic surfaces allow similar superficial roughness to that of glazed surfaces. twenty-five vitadur alpha ceramic discs (5 mm x 2 mm) were prepared according to the manufacturer's specifications. all specimens were glazed and randomly assigned to 5 groups (n=5), according to finishing and polishing protocols: g1: glazed (control); g2: diamond bur finishing; g3: g2 + silicon rubber tip polishing; g4: g3 + felt disc/diamond polishing paste; g5: g3 + felt disc impregnated with fine-particle diamond paste. next, surface roughness means (ra - μm) were calculated. qualitative analysis was made by scanning electron microscopy. surface roughness data were submitted to anova and tukey's test at 5% significance level. g1 and g4 were statistically similar (p>0.05). g2 presented the highest roughness means (p<0.05) followed by groups g3, g5, g4 and g1 in a decreasing order. the hypothesis was partially confirmed as only the mechanical polishing (g4) produced similar superficial roughness to that of surface glazing, although finishing and polishing are technically critical procedures.
Surface finishing of unused rotary endodontic instruments: a SEM study
Chianello, Giovani;Specian, Vivyane Leal;Hardt, Lilian Cristina Fucuda;Raldi, Denise Pontes;Lage-Marques, José Luiz;Habitante, Sandra Márcia;
Brazilian Dental Journal , 2008, DOI: 10.1590/S0103-64402008000200004
Abstract: during endodontic therapy, cleaning of root canals is performed using endodontic files and auxiliary chemical substances, and it is important that the endodontist be familiar with the instruments used in daily practice. this study evaluated, under scanning electron microscopy (sem), the quality of the surface finishing of unused rotary endodontic instruments. fifty sizes 20, 25 and 30 rotary files from different commercial brands (profile, protaper, race, hero and k3 endo) were removed directly from their packages and had their final 3 mm examined with a scanning electron microscope at x190 magnification with no previous preparation. the images were evaluated by 3 skillful, calibrated, blinded observers according to the following criteria: cutting edge, debris, grooves, microcavities, tip shape, tip position, scraping and transition angle. data were recorded in worksheets designed for the study. irregular edges were observed in 50-100% of the files. except for profile, all commercial brands presented surface debris in 100% of samples. only race files showed no grooves or microcavities. k3 endo files presented the best tip centralization. excetp for protaper files, all commercial brands presented blunt-cutting edges in 100% of samples. all types of files presented surface scraping. k3 endo files and protaper had a high percentage of transition angle. based on the evaluation criteria used in the present study, most samples presented a minimum of 2 alterations and a maximum of 7 alterations per instrument. under the tested conditions, the quality of the surface finishing of the examined instruments was not as expected, given that no instrument was free of imperfections and most of them presented at least 2 and up to 7 types of surface defects. these results suggest that the manufacturing process and the packaging conditions of rotary endodontic instruments are far from ideal.
The influence of the surface finishing on the electrochemical behaviour of DIN 1.4404 and DIN 1.4410 steels
Costa,S. A.; Pimenta,G.; Fonseca,I. T. E.;
Corros?o e Protec??o de Materiais , 2009,
Abstract: it is well known that the breakdown potential (eb) and the open circuit potential (eocp) are important parameters to evaluate the resistance of metallic materials against corrosion. nevertheless, the literature presents scattered values of these parameters for stainless steels (ss). many factors may contribute to this dispersion of published eb and eocp values. it has been proposed that the finishing and/or final treatment of the surface is one of those factors. to address this question, the influence of the surface finishing on the average roughness (ra), residual stress (t) and electrochemical behaviour of din 1.4404 and din 1.4410 have been considered. samples from both steels were prepared with different finishing degrees with sic paper. roughness, residual stress and electrochemical tests were performed on samples with various surface finishing. electrochemical studies were conducted in an avesta cell and steel electrodes immersed in 1 m nacl or 0.5 m mgcl2 aqueous solutions. we found that when steels are immersed in sodium chloride or magnesium chloride aqueous solutions there is no significant change in the variation of the eocp and eb values as the average roughness increases and therefore we can conclude that these parameters are not affected by the final treatment or by the solution composition.
Turning-form electrode in ultrasonic-aided electrochemical finishing
P.S. Pa
Journal of Achievements in Materials and Manufacturing Engineering , 2007,
Abstract: Purpose: The ultrasonic-aided electrochemical finishing following traditional turning by a turning-form electrode for several die materials is demonstrated.Design/methodology/approach: A guide line for the design process is followed a scientific method including the design requirement, design development, detail design, and experimental analysis is adopted in the current study. The proposed design of turning-form electrode combined with the ultrasonic-aided electrochemical finishing is presented.Findings: Smaller end radius and smaller declination angle are associated with higher current density and provides larger discharge space and better polishing effect. The plate-shape electrode with small end radius and decreasing the surface area of top-view performs the best. The ultrasonic assistance can avoid the difficulty of dreg discharge in the electrochemical finishing, thus increasing the finishing effect.Research limitations/implications: The potential for electrode design and using ultrasonic energy transmitted to the electrolyte to assist discharging dregs out of electrode gap during the electrochemical finishing is yet to be explored.Practical implications: This process can be used for various turning operations including end turning, form turning, and flute and thread cutting. Through simple equipment attachment, the electrochemical finishing can follow the cutting on the same machine and chuck.Originality/value: It is a great contribution that the ultrasonic-aided electrochemical finishing after turning process just needs quite short time than manual or machine finishing to make the surface of workpiece smooth and bright. An effective and low-cost finishing method after turning process is presented.
Influência da rugosidade na resistência à corros?o por pite em pe?as torneadas de a?o inoxidável superaustenítico
Gravalos, Márcio Tadeu;Martins, Marcelo;Diniz, Anselmo Eduardo;Mei, Paulo Roberto;
Rem: Revista Escola de Minas , 2010, DOI: 10.1590/S0370-44672010000100013
Abstract: pitting corrosion resistance has been correlated to the morphological conditions of the surface: a smooth surface finishing decreases the potential for pitting. this study aimed at investigating the relationship between pitting corrosion resistance and surface roughness in the machined surfaces of superaustenitic stainless steel astm a744 grade cn3mn. the samples of the casting steel were cylindrically turned sunder different combinations of cutting conditions, producing different surface roughness patterns. the surfaces of the samples, as machined, were characterized by roughness and hardness. after the application of an accelerated immersion corrosion test, these surfaces were examined in a stereoscope and the weight loss by corrosion was also determined. it was revealed that the samples exhibited different corrosion resistance behaviors, according to the machining conditions applied. a correlation between pitting resistance corrosion and machined surface roughness was evident, and also, the weight loss due to the formation of pits. this study has identified that corrosion can be controlled through the selection of appropriate machining parameters.
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