Cut Angle Research Articles

Yellow and Orange Light Selectable Output Generated by Nd:YAP/YVO4/LBO Raman Laser

We propose a Nd:YAP/YVO4/LBO Raman laser for visible emission with yellow and orange selectable output. A diode-end-pumped acousto-optic $Q$ -switched Nd:YAP laser at $1.08~\mu \text{m}$ was used to drive an a-cut YVO4 crystal for the Raman operation with the first-Stokes wavelength at $1.2~\mu \text{m}$ . A noncritical phase-matching angle cut LBO crystal with 20-mm length was adopted for $\chi $ (2) non-linear frequency conversion. Both the orange light at 597.4 nm and the yellow light at 567.2 nm were achieved while the LBO crystal surface temperature was controlled at 29.5 °C and 76.8 °C, respectively. Under an absorbed pump power of 6.01 W and a pulse repetition frequency of 20 kHz, 508 mW orange, and 305 mW yellow outputs were obtained based on second-harmonic generation of the first-Stokes wave and sum-frequency generation between the fundamental and the first-Stokes waves.

Analysis of longitudinal leaky surface acoustic wave propagation characteristics on a piezoelectric ScAlN layer/sapphire or quartz substrate

Longitudinal leaky surface acoustic wave (LLSAW) modes with a high phase velocity are suitable for high-frequency SAW filter applications. However, their attenuation is higher than that of other SAW modes, causing a small Q factor. On the other hand, a low attenuation and high coupling factor K2 in LLSAWs on a piezoelectric thin plate/high-velocity sapphire or quartz substrate have been demonstrated theoretically and experimentally. We expected that LLSAWs propagating on a highly piezoelectric ScAlN layer/sapphire or quartz substrate also have a high phase velocity, high K2 and low attenuation. In this study, the characteristics of LLSAWs on ScAlN layer/sapphire or quartz substrates were theoretically investigated. The cut angle and SAW propagation direction of quartz substrates strongly affect the attenuation of LLSAWs on the layered structure. We found that a LLSAW resonator with (0° 90° 90°) Sc0.4Al0.6N layer/X-cut 30° Y propagation quartz has a high Q factor and high K2, which is adequate for SAW filter applications.

Hybrid optimal scheme for minimizing machining force and surface roughness in hard turning of AISI 52100 steel

In the present work hard turning of AISI 52100 steel has been performed using PCBN tools. The input parameters considered are cutting speed, feed, depth of cut, Nose radius and negative rake angle and the measured responses are machining force (FM) and surface roughness (Ra). Experiments are planned as per Center Composite rotatable Design (CCD) of Response Surface Methodology (RSM). Investigative analysis on the effect of input parameters on the response is carried out using main effects plot and response surface plots. Further, a multi-objective optimization is performed with RSM and Grey Relational Analysis (GRA) integrated with Principle Component Analysis (PCA). Results demonstrated that negative rake angle is the paramount factor affecting the response followed by feed, speed, depth of cut, and nose radius. The optimum cutting parameters obtained are cutting speed 1000 rpm, feed 0.02 mm/rev, depth of cut 0.4 mm, Nose radius 1 mm and Negative rake angle 5°Keywords: Hard turning, AISI 52100 steel, Machining force, Surface roughness, Grey relational analysis

Effect of Rake Angle and Feed Rate on Chip Segmentation in Machining Carbon Steel 1050

A chip breaker plays an essential role for chip breaking as well as to enhance productivity and quality during the turning process. However, chip break as a tool is not able to break the chip and formulate continuous chip, that in turn, causes the tool to wear and the generate excessive heat. These affect the quality of the machined surface. Chip formation is influenced by cutting conditions and tool geometries such as spindle speed, feed rate, depth of cut and rake angle. In this study, experiments were carried out on carbon steel 1050 with chip breaker at a constant cutting speed of 275 m/mm with a depth of cut 0.9 mm. The effect of different feed rate and rake angle towards chip length formation were also investigated in the present investigation. The results obtained from the study indicates that segmented chips could be obtained at a feed rate of 0.4 mm/rev and a rake angle of -9°. Therefore, it could be concluded that the feed rate and rake angle can play a significant role in the formation of the segmented chip through the use of a chip breaker to enhance the productivity and quality in the machining process.

Verification and measurement of the side-cut angle of corneal flap in patients undergoing LASIK surgery using FS 200 kHz femtosecond laser system versus conventional mechanical microkeratome.

Introduction: This is a prospective nonrandomized interventional clinical trial conducted to measure and verify the intended versus the achieved LASIK flap side-cut angle in two groups of patients, Femtosecond laser-assisted in-situ keratomileusis (FS-LASIK) using Wavelight FS200 (Alcon Laboratories Inc. Fort Worth, TX, USA) and the conventional mechanical microkeratme (Moria M2 90).Methods: This prospective clinical trial was conducted on 40 eyes of 20 patients (20 eyes in each group) in the interval between December 2017 and August 2018. Heidelberg anterior segment OCT was done for the patients 2 weeks postoperatively to measure the corneal flap side cut angle.Results: The achieved side-cut angles of all the patients in the first group (the femtosecond laser-assisted in-situ keratomileusis group) were equal to or more inverted than the intended angle (110–115°) in all the study candidates with a minimum angle (110°) and maximum angle (155°). Unlike the achieved side-cut angle in the second group (the mechanical microkeratome group) in which all the achieved side-cut angle were acute with a minimum angle (30°) and maximum angle (65°) which is more acute than the intended side-cut angle (70°).Conclusion: In our study we found that the femtoLASIK technology was capable of making the flap side-cut angle more obtuse than the intended angle, unlike the achieved flap side-cut angle done using the mechanical microkeratome which was more acute than the intended angle in 100% of cases.

The Influence of the Angle of the Output Cut of a Cylindrical Channel on the Formation of Jets of Heated Gas and Overheated Liquid

The results of experimental research on the horizontal discharge of heated gas and overheated water through nozzles with channels having a round cross-section and different cutoff angles of the outlet aperture are presented. The processes of liquids and gases discharge are visualized via photographic survey and thermal-imaging diagnostics. Comparative analysis of the main characteristics of liquid and gas jets discharged at different initial conditions and channels of different configurations is performed. It is established that there is no shift in the jet axis with respect to the outlet-aperture axis during the discharge of heated gas through nozzles with a cutoff. Different behavior is observed during the discharge of overheated water through nozzles with a cutoff. In this case the jet axis is shifted towards the cutoff direction with respect to the outlet-aperture axis, which is in the interval 15°–18° depending on the initial conditions. Practical recommendations on the use of the discovered mechanisms in engine technology (during fuel atomization by nozzles) are suggested based on the research results.

Prediction of Surface Roughness for Development of Smart Milling Machine

The primary aim of manufacturing industry is to reduce manufacturing costs to the level that is as low as possible without reducing the quality of products. In the machining process of metal parts and features, smart milling process is being projected for materials removal process of both metal and non-metal with complex forms and finishing well. Measuring a quality of an efficient milling process is normally to be a base on the quality of the finished surface roughness. The affect several attributes of components of the surface roughness, such as ability to distribute the lubricant, load bearing capacity, heat transmission, light reflection, the contact causing surface friction, load bearing capacity, light reflection, coating or resisting fatigue with the aim to increase the quality of machined products and to reduce the cost of production in manufacturing. These can be achieved by determining the parameters of the metal cutting and machining process correctly and accurately. In this review paper, a comparative study is proposed in the form of regression method that is able to predict the surface roughness at several cutting parameters such as spindle revolution, cutting speed, feeding speed, depth of cut (DOC), length of cut (LOC), helix angle and nose radius of cut.

The correlation between lower extremity morphometric and the presence of knee osteoarthritis symptoms in indonesian mongoloid population with knee osteoarthritis

Introduction: Knee osteoarthritis is the most common joint disease. The risk factors for knee osteoarthritis are lifestyle, obesity, history of knee injury, sex, and also race. Different race may also have different body habitus, including lower extremity shape, therefore it is important to study the morphometric parameters of the lower extremity. In this study, the morphometric parameters of lower extremity and body mass index in Indonesian Mongoloid population were measured to see their correlation with the presence of symptom of knee osteoarthritis. Methods: This study was a cross sectional study. The subjects of this study weremale and female with knee osteoarthritis KL grade 2 or more who agreed toparticipate in this study. From the physical examination, the subjects were then classified into symptomatic and asymptomatic knee osteoarthritis. The lower extremity morphometric parameters that weremeasured in this study: (1) Femoral Valgus Cut Angle (FVCA), (2) Neck Shaft Angle (NSA), (3) Femoral Head Offset (FHO), (4) Trans-Epicondylar Axis (TEA), (5) Tibial Bone Varus Angle (TBVA), and (6) Patellar Morphometry, which were measured by scanogramct scan. Body mass index was measured and classified into normal, overweight, and obese. Results: Fifty-eight subjects were included in this study, 38 male and 20 female. From the 58 subjects, 37 had symptomatic knee osteoarthritis and 21 had asymptomatic knee osteoarthritis. An increase in the Neck Shaft Angle (right OR=6.51, p 0,05). The data showed that Femoral Valgus Cut Angle (p 0,05) among male and female of Indonesian Mongoloid Population. Another finding was that BMI had a statistically significant correlation with the presence of symptom ofknee osteoarthritis with a positive and very strong correlation (r=0.776, p<0.05). Conclusion: From six lower extremity morphometries in Indonesian Mongoloid population, only Neck shaft angle that had a statistically significant correlation with the presence of knee osteoarthritis symptoms. FVCA and Patellar Morphometry, however, were found to be statistically different between the male and female patients with knee osteoarthritis. BMI also had statistically significant correlation with the presence of symptom in knee osteoarthritis patients of Indonesian Mongoloid population.

Movement time and guidance accuracy in teleoperation of robotic vehicles

Two experiments are reported on the steering of a tracked vehicle through straight-line courses and corners to determine the relationships between movement time and control accuracy with the geometry of the course, such as the vehicle width, the track width and the type of corner. For straight line tracking, Drury’s law in which movement time (MT) is linear with the tracking task difficulty measure [A/(W − d)] is found to hold, where A is the distance traveled, ‘W’ is the track width and ‘d’ is the vehicle width. Performance in three types of corners (right angle, cut angle and circular) varied little, with the most important factor being the clearance (W − d) available to the operator. Collisions with boundary walls were also highly related to this factor. The reported research has strong relevance to the training of operators for urban search and rescue robots.Practitioner summary: Data for steering a real vehicle in a simulated environment of straight paths and different corner geometries showed that Drury’s law holds for straight line tracking and the clearance between the widths of vehicle and track is important in steering corners. Data show clear need for training of USAR (Urban Search and Rescue) operators.

Principal Component Analysis of the Associations Between Kinetic Variables in Cutting and Jumping, and Cutting Performance Outcome.

Welch, N, Richter, C, Moran, K, and Franklyn-Miller, A. Principal component analysis of the associations between kinetic variables in cutting and jumping, and cutting performance outcome. J Strength Cond Res 35(7): 1848-1855, 2021-The primary aim of this study was to determine which features within the ground reaction force (GRF) trace during cutting are related to performance outcome in different angled cuts. The secondary aim was to understand the relationship between GRF features in a series of maximum strength, explosive strength, and reactive strength tests, and cutting performance outcome. Twenty-five male intercounty Gaelic football players (23.5 ± 4.2 years, 183 ± 6 cm, and 83 ± 6.9 kg) participated in the study. Subjects completed 110 and 45° cutting tasks, single leg squat jumps, drop landings, drop jumps, and isometric midthigh pulls. A principal component (PC) analysis and simulation approach were applied to the data and correlations between PCs and cutting performance outcome measured. Lower vertical to horizontal impulse ratios (r = -0.70 to -0.46) in both cuts and greater forces over the first 50 ms of ground contact (r = -0.44) in the 110° cut correlated with enhanced cutting performance outcomes. Greater reactive strength index and height in the drop jump (r = -0.51 and -0.54) and greater impulses over the first 25 ms of ground contact in the drop landing (r = 0.49 and 0.70) correlated with enhanced cutting performance outcomes. These results highlight the importance of greater horizontal and rapid force production in cutting and greater reactive strength qualities to enhance cutting performance.

Non-refracted extraordinary rays in a uniaxial crystal.

We theoretically investigate non-refracted extraordinary rays where the ray does not change its direction when transmitted from a vacuum into a uniaxial crystal, even at oblique incidence. This is possible only when the optic axis is in the plane of incidence. We find that within the usual birefringence range of no≤ne≤no2, for a given angle of cut, there exits only one angle of incidence that produces a non-refracted extraordinary ray. Beyond this range, the number of solutions may be up to three. Numerical examples are given. All cases can be solved algebraically from a quartic equation.

Principal Component Analysis of the Biomechanical Factors Associated With Performance During Cutting.

Welch, N, Richter, C, Franklyn-Miller, A, and Moran, K. Principal component analysis of the biomechanical factors associated with performance during cutting. J Strength Cond Res 35(6): 1715-1723, 2021-The main aim of the current study was to investigate the relationship between kinematic variables in cutting and performance outcome across different angled cuts through the use of principal component analysis and permutation testing. Twenty-five male intercounty Gaelic football players (23.5 ± 4.2 years, 183 ± 6 cm, and 83 ± 6.9 kg) participated in the study. Three-dimensional motion capture was used to perform a biomechanical analysis of 110 and 45° cutting tasks. Principal component analysis and permutation testing revealed one principal component within the 45° cut (r = 0.26) and 2 principal components within the 110° (r = 0.66 and 0.27) cut that consistently correlated with performance outcome. Within the 45° cut, the identified principal component was interpreted as relating to performance cues of maintaining a low center of mass during the concentric phase, using a shorter ground contact time, resisting a reduction in lateral center of mass to ankle and knee distance in the eccentric phase, and using faster and larger extensions of the hip and knee. Within the 110° cut, the first identified principal component was interpreted as relating to performance cues of maintaining a low center of mass during the concentric phase, using a shorter ground contact time, resisting a reduction in lateral center of mass to ankle and knee distance in the eccentric phase, and resisting hip flexion then using hip extension. The second principal component was interpreted as relating to a performance cue of leaning in the direction of the cut.

Machinability and characterisation of machined hole on quartz using developed µ-AJM set-up

ABSTRACTMicro-abrasive jet machining (µ-AJM) is one of the novel machining processes used for machining brittle materials wherein the mechanism of erosion is brittle fracture and for ductile materials wherein the mechanism of erosion is due to shear fracture on the materials. In the current work, an attempt has been made to find the material removal rate (MRR) and characterisation of micro-holes produced on quartz using silicon carbide abrasives of various grit sizes. The process parameters selected are air pressure, stand of distance (SOD) and abrasive grit size and output responses measured for the experiments are MRR, radial over cut (ROC) and taper angle. Taguchi L16 orthogonal array has been selected to conduct the experiments. Grey relation analysis (GRA) was utilised to optimise the process parameters to increase the MRR and at the same time reduce the taper angle and ROC. From the GRA, the obtained optimum parameters are 4 bar air pressure, 0.5 mm SOD and Mix 1 (50% of 320+ 50% of 220) for maximum MRR of 3.96 mg/min, minimum ROC of 85 µm and minimum taper angle of 5°. An improvement method has been adopted to overcome the chipping at the bottom edge of the workpiece.

Modeling of cutting forces in curvilinear peripheral milling process

Due to the increasing esthetic requirements and complex functional specifications of machined components, peripheral milling of curved geometries is becoming increasingly important in the aerospace, automotive, and the injection molds industries. However, one of the major difficulties encountered by manufacturers is that peripheral milling of the curved surfaces which is characterized by significant amount of engagement variation along the tool path causing a sudden change in cutting forces and consequently a deterioration of the surface roughness of the machined parts and lowers productivity. The present paper presents a two-dimensional machining model allowing the simulation of cutting forces including the cutting process damping in curvilinear peripheral milling. In the study, we attempt to analyze the effect of various milling parameters such as cutting speed, feed rate, axial and radial depth of cut, tool diameter, and tool helix angle on cutting forces generated by the peripheral milling of a curved surface profile. The cutting forces obtained through simulation model are compared with experimental results.

Study on the effect of samplers on the disturbance of dredger-filled soil structure by numerical simulation layering method

Through the use of the particle flow software simulation, the influences on the microscopic dynamic properties of high viscosity soft soil caused by the inner diameter, cut angle and wall thickness of the samplers were studied with the example of the dredged mud. The motion behavior of the inflection point of particle characteristics was compared in seven soil samples by dividing the soil layers. The results show that a convective displacement field of the soil particles is formed at the bottom, and the particles above the convection are mainly subject to tensile expansion while the particles below the convection are mainly compressed and contracted, which result in the regular changes in porosity and bending deformation of the soil layers. There is a synergistic relationship between the intersection of the porosity curve and the initial porosity curve and the convective position of the particle displacement field. There is a characteristic inflection point in the interlayer particle displacement with the soil layers behave as a bending deformation. The particle disturbance between the inflection points is not obvious and the particle disturbance outside the inflection points is larger. The deformation feature can be fitted to a rotating paraboloid with the lower opening and the disturbance of the seven groups soil samples can be assessed initially by the a value of the surface equation. The line connecting the inflection points of the interlayer features can be refitted to a paraboloid of rotation. The ratio of the volume of the paraboloid to the volume of the soil sample can be used to evaluate the originality of the soil sample.

Modeling and Experiment of Milling Force under All Fiber Orientation Angles in Slot Milling of Unidirectional CFRP Laminates

Milling force is an important factor in determining the machined surface quality of carbon fibre reinforced polymer (CFRP) in milling process. This paper focuses on the radial force and tangential force under different fibre orientation angles during the milling of unidirectional T800/X850 CFRP laminates. The traditional straight slot milling is replaced by the circumferential slot milling in the experiment and the idea of small scale approximation is applied in analysis of data. Using this method, the milling force under all fibre orientation angles can be obtained approximately by a single experiment and the radial force and tangential force during the milling process can be obtained through mechanical modelling. Through processing experimental data, the coefficients in the theoretical formula of CFRP milling are fitted to get a function about milling force on cut depth, feed and tool rotation angle. And this function can be used to optimise milling parameters and fibre orientation during slot milling. [Submitted 16 January 2017; Accepted 18 December 2017]

Modelling and experiment of milling force under all fibre orientation angles in slot milling of unidirectional CFRP laminates

Milling force is an important factor in determining the machined surface quality of carbon fibre reinforced polymer (CFRP) in milling process. This paper focuses on the radial force and tangential force under different fibre orientation angles during the milling of unidirectional T800/X850 CFRP laminates. The traditional straight slot milling is replaced by the circumferential slot milling in the experiment and the idea of small scale approximation is applied in analysis of data. Using this method, the milling force under all fibre orientation angles can be obtained approximately by a single experiment and the radial force and tangential force during the milling process can be obtained through mechanical modelling. Through processing experimental data, the coefficients in the theoretical formula of CFRP milling are fitted to get a function about milling force on cut depth, feed and tool rotation angle. And this function can be used to optimise milling parameters and fibre orientation during slot milling. [Submitted 16 January 2017; Accepted 18 December 2017]

Orientation of Cut Angle in Distal Tibia Derotation Osteotomy Can Create Unintended Sagittal and Coronal Plane Deformity at the Ankle

Orientation of Cut Angle in Distal Tibia Derotation Osteotomy Can Create Unintended Sagittal and Coronal Plane Deformity at the Ankle

Stress-strain state in constructions corner areas

The topical problem of investigation, development of numerical and analytical methods to research constructions, buildings and structures is stress-strain analysis of building structures with intricate shape of the boundary. Geometrically nonlinear shape of boundaries (notches, crosscuts) determines the occurrence of stress concentration zones, deformations with significant enormities and gradients. Theoretical analysis of stress-strain state (SSS) for angled cut-out zones of area boundaries under the action of ruptural forced deformations resolves itself to study the singular solutions of uniform problem of elasticity theory with degree type features. The novelty of the research in the present work is determined by the fact that SSS near the vertex of angled cut-out zones of area boundary is characterized by limit strains, similar to the stress-intensity factors KI, KII, KIII when applying force criteria in mechanics of damage. Two-dimensional Betti formula is used to determine the intensity factors as limit strains, for the area constrained by the contour-circle of small radius r = ε. The independence of the Betti integral from the integration path is taken into account, which allows us to consider the contour integral along the length of arc close to the circle r = ε. The limit strains obtained in angled cut-out zones of area boundary are analyzed depending upon the area cut apex angle and the eigenvalues of elastic problem for the case of boundary conditions homogeneous for stresses.

A modified stereographic projection approach and a free software tool for kinematic analysis of rock slope toppling failures

Toppling failure is one of the common instability modes of rock slopes. Up to date, the stereographic projection approach is still an indispensable tool for kinematic toppling failure analysis of rock slopes, since it is very convenient to perform kinematic analysis that is based on all discontinuity orientations, not just some representative values, and it visually shows the analysis results. This paper first discussed the limitations of the Goodman’s graphical approach for kinematic analysis of rock slope toppling failures, and then proposed a modified graphical approach and developed practical software in a spreadsheet of Microsoft Excel for practitioners. The discrepancy between the results obtained from Goodman’s approach and our modified approach was investigated with respect to different limit values of the intersection angle between the strikes of the slope and discontinuity (denoted as γTlim), cut slope dip angles, and discontinuity friction angles. The results showed that: (1) when γTlim = 30°, the designed slope according to the Goodman’s graphical approach might be conservative or unsafe, which is related to the cut slope angle and the friction angle of discontinuity; (2) when γTlim = 30° and cut slope dip angle ≤60°, with respect to discontinuity friction angle = 10°, 20°, 30° or 40°, the designed slope according to the Goodman’s graphical approach might be conservative; (3) when γTlim = 30° and cut slope dip angle ≥70°, with respect to discontinuity friction angle = 10°, 20°, 30° or 40°, the designed slope according to the Goodman’s graphical approach is possibly unsafe; (4) when γTlim = 30° and cut slope dip angle ≤60°, with the discontinuity friction angle increasing from 10° to 40°, the discrepancy of the critical regions determined by the two approaches increases with respect to the same values of cut slope dip angle; (5) when γTlim = 30° and cut slope dip angle ≥70°, with the discontinuity friction angle increasing from 10° to 40°, the discrepancy of the critical regions determined by the two approaches first increases and then decreases with respect to the same values of cut slope dip angle; and (6) therefore, when performing kinematic analysis of rock slope toppling failures, the modified graphical approach proposed in this paper is recommended.