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Direct writing technique is usually used in femtosecond laser two-photon micromachining. The size of the scanning step is an important factor affecting the surface quality and machining efficiency of micro devices. According to the mechanism of two-photon polymerization, combining the distribution function of light intensity and the free radical concentration theory, we establish the mathematical model of coverage of solidification unit, then analyze the effect of coverage on the machining quality and efficiency. Using the principle of exposure equivalence, we also obtained the analytic expressions of the relationship among the surface quality characteristic parameters of microdevices and the scanning step, and carried out the numerical simulation and experiment. The results show that the scanning step has little influence on the surface quality of the line when it is much smaller than the size of the solidification unit. However, with increasing scanning step, the smoothness of line surface is reduced rapidly, and the surface quality becomes much worse.

The laser damage resistance of fused silica optics depends significantly on the surface quality. In this work, anisotropic etching with inert ion beams at various ion incident angles was performed to investigate the evolution of the fused silica surface. The results show that the surface is smoothed when the incident angle is below $30^{\circ }$. However, the fused silica surface starts to become coarse owing to the formation of nanostructures on the surface when the incident angle exceeds $30^{\circ }$. Further, ion beam etching at a large incident angle of $70^{\circ }$ removes subsurface defects and less induces nanostructures, resulting in reduction of the surface roughness. The concentrations of impurities and defects are both significantly reduced after ion beam etching. The surface quality, subsurface and surface defects, and surface impurities determine the variation in the laser damage threshold of fused silica with the ion incident angle. The results demonstrate successful application of ion beam etching to improve the laser damage resistant characteristics of fused silica optics. Ion beam etching is a very versatile tool that provides physical erosion to anisotropically mitigate surface damage of fused silica.

Analysis of workpiece surface quality is one of the major issues in manufacturing engineering. Turning operation is a famous machining operation that is widely used in machining of materials. In this research, we investigate the surface finish of machined workpiece from turning operation. For this purpose, we employ fractal theory to study the complex structure of machined workpiece’s surface in different conditions. The applied parameters include the variations of cutting depth, feed rate and spindle speed in wet and dry machining conditions. Based on the obtained results, we found the correlation between the increment of fractal dimension of machined surface and the increment of cutting depth, feed rate and spindle speed in wet machining condition. The obtained results will be discussed in relation with the complexity of machined surface. The employed method of analysis in this research can be widely applied to the analysis of the effect of different machining parameters and conditions on the surface quality of machined workpiece in case of different machining operations.

Acquiring the desired surface quality is one of the major efforts in machining of materials. Milling operation is a widely used machining operation to shape the material in different forms. Machining parameters and conditions are two major factors that affect the surface quality of machined workpiece in milling operation. In this paper, we analyze the surface finish of machined workpiece under the variations of machining parameters and conditions (wet and dry conditions) in milling operation. For our analysis, we use fractal dimension as the indicator of complexity of structure. Based on the obtained results, in the case of wet machining condition, by increasing the depth of cut, feed rate and spindle speed in separate experiments, the fractal dimension of machined surface increases. However, the obtained results in the case of dry machining condition are not consistent with the variations of different machining parameters. The obtained results will be discussed in terms of complex structure of machined surface. The method of analysis employed in this research can be investigated with other machining operations to check how the machining parameters and conditions affect the surface quality of machined surface.

Drilling is a famous and widely used machining operation to make holes in the workpiece. The size and surface quality of drilled hole are two factors that should be considered mainly. In this research, we examine the effect of different machining parameters and conditions on the surface quality of generated hole in drilling operation. For this purpose, we employ fractal theory and investigate how the variations of depth of cut and spindle speed affect the complexity of surface texture of drilled holes in wet and dry machining conditions. Based on the obtained results, the increment of depth of cut and spindle speed in case of wet and dry machining causes lower complexity on the generated surface from drilling. In addition, the generated surface from dry machining is more complex than the generated surface from wet machining. The obtained method in this research can be applied to other machining operations in order to investigate the effect of machining parameters and conditions on the surface quality of machined workpiece.

AISI 4340 (34CrNiMo6) steel is a difficult to machine steel material because of its high hardness and tendency to get strain hardened. These steels are mostly used in manufacturing of the axle parts, drive coupling, and rotating shafts due to their high mechanical properties. In this experimental study, the effects of mechanical properties and microstructure on tool vibration and surface quality in dry turning of hardened AISI 4340 steels were investigated. Test samples were classified as Raw Material (RM), Conventional Heat Treatment (CHT) and Tempering process (T). The experiments were carried out under dry cutting conditions by different cutting parameters on the CNC turning lathe. Three axes vibration amplitude values (along the $x$-, $y$- and $z$-directions) were measured using accelerometers as online and surface roughness (Ra) values were measured with the surface roughness device. Tool vibrations and Ra values were found to be lower in T sample compared to the RM and CHT samples. When the samples were analyzed in terms of microstructure and mechanical properties, it was seen that the tensile strength increased as the hardness values increased. After the tempering process at 200^∘C, pearlite and bainitic structures emerged along with the martensite structure. The surface quality that can be obtained on a cylindrical grinding lathe, has been reached with the dry turning process. Significant gains have been achieved in terms of cost and time.

This study focused on determining the effects of the cooling condition in the conventional and ultrasonic-assisted turning of AISI 52100 steel. AISI 52100 steel has been widely used in the bearing, mold, and automotive industries because of its superior wear resistance and mechanical properties. However, its high wear resistance caused poor machinability in conventional machining methods. Low surface quality, rapid tool wear, high cutting temperature, and high cutting force are the main difficulties in the conventional machining of AISI 52100 steel. On the other hand, ultrasonic-assisted machining has become widely used in the past decades for the machining of materials that have low machinability in conventional methods. Conventional turning and ultrasonic-assisted turning were selected as machining methods. Ultrasonic-assisted turning experiments were conducted under 20 and 30 kHz vibration frequencies. Cubic Boron Nitride (CBN) cutting tools were used in machining experiments. In machining operations 50, 100, and 150 m/min cutting speeds were selected, and feed rate (0.1 mm/rev) and depth of cut (0.5 mm) were kept constant in experiments. Minimum quantity lubrication technique which used 1% Al₂O₃ nanoparticle additives cutting fluid and dry cooling methods were used. CBN insert was used as a cutting tool. The effects of cutting speed, cutting method, and cooling condition on surface quality, cutting force, cutting zone temperature, and cutting tool wear were studied experimentally. Analysis of Variance (ANOVA) was carried out to determine the significance of the effects of input variables on process outputs. As a result of this study, it is determined that combined UAT and nanoMQL have significant effects on the process outputs.

Analysis of surface quality of machined workpiece is an important issue in machining of materials. For this purpose, scientists analyze how the texture of machined surface changes due to different conditions. Machine vibration is one of the factors that highly affects the surface quality of machined surface. In this research, we analyze the relation between machine vibration and surface quality of machined workpiece. For this purpose, we employ fractal theory and analyze how the complex structure of machined surface changes with the complex structure of machine vibration signal in case of variations of machining parameters, namely, depth of cut, feed rate and spindle speed, in milling operation. Based on the results, variations of surface quality of machined workpiece are related with the variations of complexity of machine vibration signal. The method of analysis employed in this research can be applied to other machining operations in order to find the relation between machine vibration and surface quality of machined workpiece.

Buckypaper is a thin sheet fabricated from the aggregation of carbon nanotubes. The generally accepted method for forming such carbon nanotube (CNT) films involves the use of stable suspension of carbon nanotubes in water. These suspensions can then be membrane-filtered under pressure to yield uniform films. After preparation of a stable solution, it should be membrane-filtrated on the surface of a filter. Usually, the quality of a buckypaper depends on sonication time and power, surfactant type and concentration, filter type, and concentration of carbon nanotube. In order to investigate the surface quality of buckypapers, low-magnification images could give rather useful information about the roughness of surface. Analysis of the 100 × images clearly shows that with increasing the suspension concentration, the smoothness of buckypaper surface will decrease. Therefore, from this viewpoint, decreasing the concentration can enhance the quality of the buckypaper. Surface of the filter also affects on the buckypaper quality. Therefore, for filtration of the suspension, a filter with suitable material, pore sizes, and surface should be used. As the pore sizes of the filter are usually small, the filtration process may be very time-consuming. Since the process is carring out under pressure and also due to the brittle nature of the buckypaper, removal of the buckypaper from the surface of the filter is a very serious and important stage and depends on the filter type, concentration, and type of CNTs. The buckypaper usually can be removed from the filter mechanically. The type of CNTs (MWNT or SWNT) may change the above-mentioned factors.

Laser texturing assisted with electrochemical machining (LT-ECM) is combined the high efficiency of laser machining and the high surface quality of electrochemical machining. The light-trapping structures are mainly formed by laser action and the slag produced in laser texturing is removed by electrochemical machining. In order to obtain the better textured quality, parameters optimization for LT-ECM has been carried out in this paper. Three important parameters such as pulse laser energy and applied electrochemical have been optimized to improve the optical property of mc-Si. The textured surface reflectance (TSR) and the slag removal rate (SRR) have been used as the evaluation indicators to evaluate the textured results on mc-Si by LT-ECM. The experiments were performed on 30×30mm² mc-Si wafer with pulsed Nd:YAG laser at second harmonic wavelength and NaOH solution. The experimental results showed that pulse laser energy has the most significant influence on TSR. Applied electrochemical voltage has significant influence on SRR. Optimized parameters for LT-ECM are: pulse laser energy is about 30mJ; electrochemical applied voltage is about 15V.