Lower Surface Roughness Values Research Articles

Chemical CeO2-Based Buffer Layers for Fe(Se,Te) Films

Among other Fe-based superconductors, Fe(Se,Te) is particularly interesting because of the low structural anisotropy, large upper critical fields, low field dependence of the critical current density and low toxicity. It can also be grown as an epitaxial film on a metallic oriented substrate, making the fabrication of a Fe-based coated conductor (CC) possible. Less strict requirements on the template microstructure allow for the design of a simplified design compared to REBCO CCs. This design requires a buffer layer to promote the oriented growth of the superconducting film and avoid diffusion from the metallic template. In this work, CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> based buffer layers are prepared on single crystals via two chemical deposition techniques, metal organic decomposition (MOD) and polymer assisted deposition (PAD). With the design of a suitable thermal treatment, it is possible to obtain oriented buffers with large flat grains and low values of surface roughness. Fe(Se,Te) films are deposited on these templates via laser deposition, and excellent samples are obtained when a Fe(Se,Te) seed layer is used to favour chemical matching with the buffer: sharp superconducting transitions around 16 K and critical current densities exceeding 1 MA cm <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">⁻</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 4.2 K in self-field are observed. These results are the demonstration of the feasibility of a Fe-based CC architecture, with all the relative advantages concerning process simplification and cost reduction.

The Effect of Finishing and Polishing with Proprietary Vs Interchanged Polishing Kits on the Surface Roughness of Different Ceramic Materials.

To evaluate the surface roughness of glazed and polished monolithic ceramic materials and to use this as a baseline for comparison after adjustment and polishing with both the recommended kit for the specific materials as well as interchanged polishing kits. Flat ceramic specimens (n = 150) were fabricated from IPS ZirCAD Prime, IPS E.max, and Vitabloc Mark II. The specimens were adjusted and polished using either the proprietary polishing kit for the material or interchanged kits. The surface roughness was objectively assessed using Atomic Force Microscopy (AFM) and profilometer. Subjective assessment of surface finish was performed using a scanning electron microscope (SEM). Gravimetric weight loss of each sample was measured before and after polishing using a digital microscale. The mean surface roughness and standard deviation was calculated for each ceramic- polisher pair. A factorial ANOVA was used to compare the mean surface roughness values in nanometers between multiple groups (α = 0.05). The subjective results from the SEM were reported as descriptive statistics RESULTS: The zirconia polishing system produced surfaces with the lowest surface roughness regardless of the ceramic material. The polisher-ceramic combination was found to have a statistically significant effect on both Ra and RMS values when the AFM was used (p = 0.039 and 0.010, respectively). The zirconia polishing system resulted in the lowest surface roughness values regardless of ceramic materials tested. The zirconia polishing system also did not result in significant gravimetric weight loss regardless of the ceramic material used.

Biomedical porous scaffold fabrication using additive manufacturing technique: Porosity, surface roughness and process parameters optimization

Titanium is a most common and best biocompatible material. The demand and application of Ti alloy is increasing rapidly in orthopedics for clinical operations. The porous structures have been designed for bone tissue engineering or orthopedic applications due to its moderate Young's modulus, excellent compressive strength, biocompatibility and sufficient space for cell accommodation. The porous scaffolds with individual complex internal and external shape can be manufactured by additive manufacturing (AM) processes especially selective laser melting (SLM), both of these have great importance for repairing of large sectional bone defects. This advantage makes the SLM process one of the most competitive AM processes used in the biomedical fields. Seven different Ti–6Al–4V porous scaffolds (Diamond, Grid, Cross, Vinties, Tesseract, Star and Octet) of 15 mm cube with 65% porosity were designed using Rhino 6 software and fabricated through SLM using Ti–6Al–4V powders. This work mainly focused on porous scaffolds design and manufacturing by AM particularly SLM, can able to produce scaffolds of nanoscale grains because of its higher heating rate and lower holding time. But this process generally results insufficient compaction where desired function is not achieved. The scaffolds manufactured by SLM have relatively high accuracy of pore structure and low mechanical strength. Grid type structure exhibits lower surface roughness value and better manufacturing ability where error percentage of porosity is lower than the other scaffolds.The process parameters employed in the study like laser power, scanning speed, hatch distancing and layer thickness are the most significant factors that influence the defect behaviour and morphology of the SLM-fabricated samples. Porosity percentage and surface roughness of the scaffold palys a vital role on its desired functions. While the porosity percentage are also effected by input process parameters resulting the variation on effective elastic modulus. The increase in scanning speed leads to elevation of the cooling rate, which results in a finer microstructure. On the other hand, with lower scanning speeds, coarse microstructure is observed.

The effects of surface roughness on fully developed laminar and transitional flow friction factors and heat transfer coefficients in horizontal circular tubes

Although the effect of surface roughness on internal forced convection is considered a mature field, very limited work has been done focussing on the effect of surface roughness in the laminar and transitional flow regimes, especially for fully developed flow. Therefore, the purpose of this study was to experimentally investigate the simultaneous heat transfer and pressure drop characteristics in the laminar and transitional flow regimes for tubes with internally roughened surfaces. Experiments were performed using circular tubes with an internal diameter of 5.14 mm and a length of 5.45 m, with the smooth tube having a relative surface roughness close to 0, and the rough tubes having relative surface roughness values of 0.0003 and 0.0006. Water was used as the test fluid and the experiments were performed for Reynolds numbers between 500 and 9 800, while the Prandtl number varied between 4.32 and 7.01. Three different constant heat fluxes with values of 1, 2 and 3 kW/m2 were applied to the test section while determining the friction factors from the pressure drop measurements and the heat transfer coefficients, Nusselt numbers and Colburn j-factors, from the measured fluid and surface temperatures. The Colburn j-factors and friction factors behaved similarly throughout the tested Reynolds range and the flow regime boundaries of the heat transfer and pressure drop results corresponded well. An increase in surface roughness favoured an increase in heat transfer in the laminar flow regime, but not in the other flow regimes. When investigating the influence of surface roughness on the critical Reynolds number, three distinct regions were identified and defined, namely, the Dampening region, Enhancing region and Saturating region. For low values of relative surface roughness, the onset of transition was delayed, while transition occurred earlier as the relative surface roughness was increased to moderate and high values. General trends in all three regions were that, an increase in surface roughness decreased the width of the transitional flow regime while increasing the transition gradient.

The Influence of the Depth of Grinding on the Condition of the Surface Layer of 20MnCr5 Steel Ground with the Minimum Quantity Lubrication (MQL) Method.

This paper describes the research on abrasive machining conditions and their influence on microhardness and residual stresses distribution in the technological surface layer of 20MnCr5 steel. The roughness of ground samples was also measured. Samples underwent a vacuum carburizing process (LPC) followed by high-pressure gas quenching (HPGQ) in a 4D quenching chamber. Processes were realized with a single-piece flow method. Then, the flat surfaces of samples were ground with a Vortex type IPA60EH20VTX alumina grinding wheel using a flat-surface grinder. The samples were ground to three depths of grinding (ae = 0.01; 0.02; 0.03 mm) with grinding fluid supply using either flood method (WET) or minimum quantity lubrication (MQL) method. The condition of the technological surface layer was described using microhardness and residual stresses, as well as some selected parameters of surface roughness. The results obtained revealed that changes in microhardness as compared to microhardness of the material before grinding were lower in samples ground with grinding fluid supplied with MQL method. At the same time, the values of residual stresses were also better for samples ground using MQL method. Furthermore, the use of grinding fluid fed with MQL method produced lower values of surface roughness compared to the parameters obtained with WET method. It was concluded that for the tested scope of machining conditions, the MQL method can be a favourable alternative to the flood method of supplying grinding fluid into the grinding zone.

The Modelling of Surface Roughness after the Ball Burnishing Process with a High-Stiffness Tool by Using Regression Analysis, Artificial Neural Networks, and Support Vector Regression

Surface roughness is an important indicator of the quality of the machined surface. One of the methods that can be applied to improve surface roughness is ball burnishing. Ball burnishing is a finishing process in which a ball is rolled over the workpiece surface. Defining adequate input variables of the ball burnishing process to ensure obtaining the required surface roughness is a typical problem in scientific research. This paper presents the results of experiments to investigate ball burnishing of AISI 4130 alloy steel with a high-stiffness tool and a ceramic ball. The experiments were conducted following a randomized full factorial design for different levels of input variables. The input variables included the initial arithmetic mean roughness (the initial surface roughness), the depth of ball penetration, the burnishing feed, and the burnishing ball diameter, while the output variable was the arithmetic mean roughness after ball burnishing (the final surface roughness). The surface roughness modeling was performed based on the experimental results, using regression analysis (RA), artificial neural network (ANN), and support vector regression (SVR). The regression model displayed large prediction errors at low surface roughness values (below 1 μm), but it proved to be reliable for higher roughness values. The ANN and SVR models have excellently predicted roughness across a range of input variables. Mean percentage error (MPE) during the experimental training research was 29.727%, 0.995%, and 1.592%, and MPE in the confirmation experiments was 34.534%, 1.559%, and 2.164%, for RA, ANN, and SVR, respectively. Based on the obtained MPEs, it can be concluded that the application of ANN and SVR was adequate for modeling the ball burnishing process and prediction of the roughness of the treated surface in terms of the possibility of practical application in real industrial conditions.

Theoretical and experimental investigations of magnetic field assisted ultra-precision machining of titanium alloys

Although titanium (Ti) alloys possess unique properties that allow them to compete with many other materials in advanced industries such as aerospace, marine and biomedical, they have poor machining performances. The primary objective of this study is to investigate the distribution of magnetic field intensity at the cutting environment in single-point diamond turning (SPDT) of Ti–6Al–4 V alloy and its influence on the machining performances, with the goal of achieving the desired machining conditions of magnetic field assisted ultra-precision machining, especially magnetic field intensity and the corresponding machining parameters, and to enhance the machinability of Ti–6Al–4 V alloy. In this study, magnetic field-assisted machining (MFAM) system was designed and coupled with ultra-precision machining (UPM) using single-point diamond turning for increasing the machinability and improving the surface quality of Ti6Al4V alloy machined parts. The finite element method (FEM) was developed to demonstrate the influences of the generated magnetic field on the machining processes. The Experimental results showed the capability of magnetic field assistance to enhance the machining performance of Ti–6Al–4 V alloy. These findings provided strong evidence that a magnetic field has the ability to extend cutting tool life, additionally, MFAM achieved the lowest value of surface roughness, representing a 33 percent improvement in surface roughness. This research contributes to the support of the optimum MFAM by FEM and the achievement of high-quality machined Ti alloys in UPM for similar research works, as demonstrated by the experimental results.

Yüzey Bitirme İşlemleri ve Yaşlandırmanın Hibrit Seramik Materyalde Yüzey Pürüzlülüğü ve Renk Stabilitesine Etkisi

AIM: The aim of this study is to evaluate the effect of four different surface finishing methods and aging on the surface roughness and color stability of dental hybrid ceramic. &#x0D; &#x0D; MATERIAL AND METHODS: Hybrid ceramic blocks were prepared with dimension of 12x14x1 mm and 4 groups were determined as; polishing with technical kit (ET), polishing with clinical kit (EC), glazing of sandblasting surface (ES) and glazing of etching surface (EA) (n=10). Color parameters and surface roughness values were measured. Thermocycling procedure was applied. Color and surface roughness values were re-measured. ΔE values were calculated and data was analyzed with Kruskal Wallis, Bonferroni Dunn and Wilcoxon signed ranks tests. Surface analysis were performed with scanning electron microscope to 2 specimens of each group.&#x0D; &#x0D; RESULTS: Significant difference was not observed among ΔE values of the groups with different types of surface finishing procedure. Before and after aging, EA group had lowest surface roughness values. After aging, surface roughness values increased for ES group. &#x0D; &#x0D; CONCLUSION: The color stability of hybrid ceramic material was not affected by the surface finishing method, and the lowest surface roughness values were observed in the glazing of sandblasting surface group.

Influence of the carrier wafer during GaN etching in Cl2 plasma

In this study, we have performed a thorough characterization of the GaN surface after etching up to 100 nm in Cl2 plasma under various bias voltages and according to the carrier wafer used (Si, SiO2, Si3N4, and photoresist). The objective of this article is to evaluate the etch damage and contamination of the GaN surface when materials with other chemical nature are present during etching. The effects of etching conditions on surface morphology and chemical compositions of etched GaN films are studied in detail using XPS and AFM measurements. To this aim, a universal methodology is proposed to estimate accurately by XPS the stoichiometry of the GaN surface exposed to reactive plasmas when only an Al Kα x-ray source is available. The results indicate that the GaN etching mechanisms are very sensitive to the chlorine radical density present in the plasma, the latter being strongly influenced by the carrier wafer. Substrates that are more chemically reactive with Cl2 plasma such as silicon or photoresist compared to SiO2 or Si3N4 will lead to a greater loading of atomic chlorine, which in turn will lead to lower GaN etch rates. Moreover, the GaN surface contamination will depend on the etch by-products ejected by the carrier wafer. The GaN surface exposed to Cl2 plasma shows a Ga-depleted surface because of the more important reactivity of Cl with Ga rather than N, except in the SiO2 carrier wafer case. In this latter case, the formation of Ga–O bond limits the Ga removal. Regarding the surface roughness, it seems that the contaminants play a little role in the roughness formation except for the oxygen released by the SiO2 carrier wafer. On the other hand, the surface roughness evolution is clearly driven by the chlorine radical flux reaching the GaN surface. At low bias voltage, a preferential crystalline orientation etching driven by the Cl radicals leads to the formation of hexagonal shaped defects that are associated to screw-type threading dislocations already present in the pristine GaN material. At higher bias, the enlargement of the defects is limited, leading to a very low surface roughness value but to amorphized surfaces.

Effect of Machining Parameters on Tool Life and Surface Roughness of AISI 1040 Dual Phase Steel

The purpose of this research is to investigate the effect of heat treatment parameters on the tool life and surface roughness of dual phase steel. Optimization of machining parameters (cutting speed, feed and depth of cut) is carried out for the machinability tests on medium carbon low alloy steel. Taguchi’s method of design is used to carry out machinability tests. Analysis of variance (ANOVA) is carried out to determine the relative contribution of machining parameters on tool life and surface roughness. Microstructure analysis is carried out to ascertain the machining behavior of the steel. Results have shown that, depth of cut and cutting speed are the most significant factors contributing on the variation of the tool life and surface roughness. Optimized machining parameters are calculated in order to obtain higher tool life and lower surface roughness value.

The effects of current production techniques on the surface roughness, oxide layer thickness and porcelain bond strength of cobalt-chromium and titanium substructures

Aim: This study aimed to evaluate the oxide layer, surface roughness, and bond strength with porcelain of cobalt-chromium (Co-Cr) and titanium (Ti) substructures produced using casting, milling and selective laser sintering techniques.&#x0D; Methodology: A total of 180 disc-shaped metal samples with a diameter of 1 cm and a thickness of 3 mm were produced. The samples were divided into six groups (n=15) according to the technique used to produce the metal substructures—casting, milling, and SLS—and the chemical composition of the metal substructure—Co-Cr and Ti. Then roughness averages (Ra) of the sample surfaced were calculated with a contact-type profilometer. Nondestructive energy-dispersive X-ray was performed to ensure that the layer displayed in contrast was the oxide layer, and the average oxide layer thickness was calculated from scanning electron microscope images. Metal-porcelain complexes were subjected to shear bond strength test and failure types were noted. Two-way multivariate analysis of variance (MANOVA) was used to compare oxide layer thickness, surface roughness, and shear bond strength according to the metal and production technique, and Tukey’s honestly significant difference (HSD) test was used for multiple comparisons of the main effects.&#x0D; Results: Two-way MANOVA revealed that the metal and technique used in the substructure production had significant effects on surface roughness, oxide layer thickness and shear bond strength (p &lt; 0.001). Ti groups exhibited thicker oxide layer formation than Co-Cr groups. Low surface roughness values were observed in the milling groups. The highest shear bond strength value (53.8 MPa) was observed in the Co-Cr group produced by casting, while the lowest value (32.2 MPa) was obtained in the Ti group produced by casting.&#x0D; Conclusion: It should be kept in mind that there is no ideal production technique and that the effects of the production technique differ depending on the metal used.&#x0D; &#x0D; How to cite this article: Ünalan Değirmenci B, Ersoy NM. The effects of current production techniques on the surface roughness, oxide layer thickness and porcelain bond strength of cobalt-chromium and titanium substructures. Int Dent Res 2021;11(3):129-39. https://doi.org/10.5577/intdentres.2021.vol11.no3.1&#x0D; &#x0D; Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Evaluation of Different Beverages’ Effect on Microhardness and Surface Roughness of Different Artificial Teeth

Purpose: This study evaluated the microhardness and surface roughness of four artificial teeth type against various beverages. Materials and Methods: Conventional acrylic resin, reinforced acrylic resin, microfiller composite resin, and nanofiller composite resin teeth were used. From each group, 10 maxillary first and second molars were immersed in 5 beverages (tea, filtered coffee, cola, cherry juice, and distilled water. The test period of 24 hours appears comparable to approximately 1 month of normal beverage consumption. The test periods used in this study were arranged according to this protocol and 1 week, 1 month, 3 months and 6 months of normal beverage consumptions were simulated. Vickers microhardness and surface roughness of denture teeth were measured for each test period. Results: The microhardness values significantly decreased in all beverages especially in 6th month. The surface roughness values significantly increased in all beverages especially in 3th month. There were no statistically significant differences between the beverages. Microfiller composite resin denture teeth had the highest microhardness values and the lowest surface roughness values. Conclusions: Different types of beverages consumed daily negatively affect the microhardness and surface roughness of artificial teeth. Microfiller composite resin teeth could have the ideal surface properties

Analisa parameter pada pemotongan plate menggunakan CNC fiber laser cutting terhadap kekasaran permukaan

With the advancement of advanced equipment, Computer Numerical Control (CNC) laser cutting as a manufacturing tool in plate cutting, where industri player make to get maximum result. Laser cutting Cutting is one of the tools used by the industrial world to maximize cutting results. The purpose of this research To find out the results of the difference using the parameters of air pressure and cutting speed on a Q235B carbon steel plate with a thickness of 3 mm using CNC fiber laser cutting on the surface roughness of the material. The method used in this study is a real experimental research method and data analysis to analyze parameters on plate cutting using laser cutting on surface roughness with this number of experiments 9 and 3 replications for the research process by testing surface roughness using Surface Roughness Sj – 210 Mitutoyo. The results showed that the higher the air pressure and the lower the cutting speed, the lower the surface roughness value and vice versa. The lowest surface roughness value is at air pressure of 16 Bar with a cutting speed of 3300/min which is getting a value of 1.499 μm and the highest surface roughness value is at air pressure of 12 bar with a cutting speed of 3400 mm/min which is getting a value of 2.986 μm. dengan kecepatan pemotongan 3400 mm/min yaitu mendapatkan nilai sebesar 2,986 μm.

Effect of building orientation & heat-treatment on microhardness & surface roughness of additive manufactured IN718 alloy

By offering better mechanical and physical properties, additively manufactured Inconel alloy can replace cast Inconel alloy in the aerospace, defense, and marine industries. This paper covers the building orientation and heat treatment effects on microhardness and surface roughness of additively manufactured IN718 alloy. Samples were built in three orientations (0°, 45°, and 90°) and subsequently heat-treated at 1080 °C/1 h (homogenization), 960 °C/1 h (solution treatment), and 720 °C/8 h (ageing). The Vickers hardness test and surface roughness test were performed before and after heat treatment. The results obtained from the tests were analyzed. A nearly 14.02% higher micro-hardness value (391.50 HV) was observed for 90° built samples heat-treated at 720 °C compared to 90° as-built samples, and a nearly 13.62% lower surface roughness value (2.60 µm) was observed for 45° built samples heat-treated at 960 °C compared to 45° as-built samples. The increase in the hardness value was observed due to the formation of γ′ and γ″ phases in the γ matrix. The surface roughness was lower for 45° built, but no significant changes were observed in surface roughness after performing different heat treatments.

Development of a Low Cost Eco-Friendly Minimum Quantity Lubrication System for Machining Processes

Recently all environmental worries are calling for reducing the usage of fluids in machining operations. One of the promising solutions that appeared lately is minimum quantity lubrication (MQL). This research aimed to develop an eco-friendly cooling system for a lathe machine and assess its performance. After considering the customer needs, the needs were translated into engineering specifications in the conceptual design phase, and then the quality function deployment was developed. Three concepts were generated and evaluated considering the selection criteria, and a final concept was selected using the decision matrix method. Following this, a detailed design and fabrication of the sub-systems such as the oil tank and a structure accommodate all the components. The developed system was tested on six different workpiece samples to compare the MQL system with the conventional one. In general, the MQL system resulted in lower surface roughness values as well as lower tool wear.

Investigation on Microstructure, Nanohardness and Corrosion Response of Laser Cladded Colmonoy-6 Particles on 316L Steel Substrate.

316L steel is predominantly used in manufacturing the components of high-pressure boilers, heat exchangers, aerospace engines, oil and gas refineries, etc. Its notable percentage of chromium offers resistance against corrosion and is mostly implemented in harsh environments. However, long-term exposure to these components in such environments can reduce their corrosion resistance property. Particularly at high temperatures, the oxide film formed on this type of steel reacts with the chloride, sulfides, sulfates, fluorides and forms intermetallic compounds which affect its resistance, followed by failures and losses. This work is focused on investigating the hardness, microstructure and corrosion resistance of the laser cladded Colmonoy-6 particles on the 316L steel substrate. The cladded specimens were dissected into cubic shapes and the microstructure present in the cladded region was effectively analyzed using the FESEM along with the corresponding EDS mapping. For evaluating the hardness of the cladded samples, the nanoindentation technique was performed using the TI980 TriboIndenter and the values were measured. The potentiodynamic polarization curves were plotted for both the substrate and clad samples at 0, 18, 42 and 70 h for revealing the corrosion resistance behavior. In addition, the EIS analysis was carried out to further confirm the resistance offered by the samples. The surface roughness morphology was evaluated after the corrosion process using the laser microscope, and the roughness values were measured and compared with the substrate samples. The result showed that the cladded samples experience greater hardness, lower values of surface roughness and provide better corrosion resistance when compared with substrate samples. This is due to the deposition of precipitates of chromium-rich carbide and borides that enhances the above properties and forms a stable passive film that resists corrosion during the corrosion process.

Investigation of the Effect of Drill Bit Feature on Hole Surface Quality and Tool Wear

Drilling operations have an important role in manufacturing industries and the application range is about 33% among the machining methods. In drilling processes, hole quality is affected by workpiece material, drilling parameters, drill diameter, drill bit features. In this study, the surface quality of the hole and the drill bit wear were investigated experimentally when drilling AISI 1040 steel and Al7075 aluminum workpieces with twist drills. Three different types of twist drill bits (polished, rolled and TiN coated) with diameters of 8 mm and 10 mm were used for drilling. Hole surface roughness was investigated at the hole entry and hole exit. While revealing the surface quality change at the hole entry-exit, the effect of the drill feature difference on the surface quality has been tried to be determined. In general, hole surface quality decreased with increasing drill bit diameter when drilling both materials. The lowest surface roughness values were obtained in the use of TiN coated drill bits. Drill bit wear was also measured in the study, and it was seen that the drill bit wear increased with increasing drill bit diameter. The least drill bit wear value was also observed in TiN coated drill bits.

Investigation of surface roughness values of various restorative materials after brushing with blue covarine containing whitening toothpaste by two different methods: AFM and profilometer.

The aim of this study is to evaluate the effect of whitening toothpaste on the surface roughness of resin-based restorative materials by different measurement methods. Twenty four specimens from each of human enamel, a microhybrid composite and two nanohybrid composites discs (8.0 diameter × 4.0 mm thick) were divided into two groups (n=12) according to toothbrushing solutıon and subjected to simulation toothbrushing (30,000 cycles) with both distilled water and whitening toothpaste containing blue covarine. Surface roughness was examined using atomic force microscopy (AFM), profilometer, and scanning electron microscopy (SEM), and the data obtained were subjected to analysis. Ra values of Tescera (TES) were significantly higher than Sonicfill 2 (SF2) when brushing both toothbrushing solutions for initial or 30,000 cycles. Roughness increased for SF2 and TES when brushed for 30,000 cycles and was higher than enamel and Herculite XRV Ultra (HXU). Human enamel was obtained lower surface roughness values brushed with toothpaste compared with distilled water. Evaluation of the surface roughness of control groups using the AFM revealed no statistically significant difference between the groups, but significant differences were found using a profilometer. The use of abrasive whitening toothpaste containing blue covarine and the number of brushing cycles affect the surface properties of human enamel and the restorative material, and also, the clinical success of the restoration. Toothbrushing for 30,000 cycles increased the surface roughness of all materials. The type of toothbrushing solution partially has affected surface roughness.

Influence of Part Orientation on the Surface Roughness in the Process of Fused Deposition Modeling

The article focused on the influence of part orientation on the surface roughness of cuboid parts during the process of fabricating by FDM technology. The components, in this case, is simple cuboid part with the dimensions 15 mm x 15mm x 30 mm. A geometrical model is defined that considers the shape of the material filaments after deposition, to define a theoretical roughness profile, for a certain print orientation angle. Five different print orientations in the X-axis of the cuboid part were set: 0°, 30°, 45°, 60°, and 90°. According to previous research in the field of FDM technology by the author, the internal structure (infill) was set at the value of 70%. The method of 3D printing was the Fused Deposition Modeling (FDM) and the material used in this research was thermoplastic ABS (Acrylonitrile butadiene styrene). For each setting, there were five specimens (twenty five prints in total). Prints were fabricated on a Zortrax M200 3D printer. After the 3D printing, the surface “A” was investigated by portable surface roughness tester Mitutoyo SJ-210. Surface roughness in the article is shown in the form of graphs (Fig.7). Results show increase in part roughness with increasing degree of part orientation. When the direction of applied layers on the measured surface was horizontal, significant improvement in surface roughness was observed. Findings in this paper can be taken into consideration when designing parts, as they can contribute in achieving lower surface roughness values.

Investigation on Surface Condition of the Corona-Aged Silicone Rubber Nanocomposite Adopting Wavelet and LIBS Technique

Silicone rubber nanocomposites were prepared using 1, 3, 5, and 10 wt% of alumina nanofiller. Corona inception voltage (CIV) due to water droplets was measured using fluorescence technique, and it has decreased for alumina-added silicone rubber nanocomposites and with corona-aged samples. The effect of the corona discharges on the surface morphology characteristics of the nanocomposites was analyzed by measuring contact angle, surface profile measurement using atomic force microscopy (AFM), and characterized by adopting multiresolution signal decomposition (MRSD) technique. The addition of the alumina nanofiller suppressed the surface roughness for the corona-aged nanocomposites and 5-wt% sample observed to have the lowest surface roughness values. Recovery of the surface roughness caused by corona discharges was analyzed at different time intervals, and it was observed that alumina nanoparticle-added silicone rubber showed an incremental reduction in the roughness recovery rate. The laser-induced breakdown spectroscopy (LIBS) technique was adopted to analyze the nanocomposites after the corona aging, and further plasma temperature was evaluated at different recovery times. The addition of an alumina nanofiller increased the plasma temperature, and 5-wt% samples have the lowest plasma temperature recovery rate after corona aging. The analysis of the study indicates that the corona-aged silicone rubber specimen surface properties recover in 8 h of resting time period.