Modeling mated surfaces with the required parameters

This paper has proposed improving the methods of circular and screw conversion, to be used in the design of cutting tools and toothing that include complex mated surfaces. Underlying the improvement of both methods is the construction of a mathematical base and the development of a computer subprogram, based on it, in the MATLAB system. During the research, the original screw-type curved surface and the curvilinear generatrix axis were formed on the basis of improved methods, taking into consideration the exclusion of interference at the design stage. A comprehensive solution to this problem is important for the manufacture of products by rolling. Given this, the original instrumental surface of the cutting tool takes into consideration the pairing condition between the article’s and tool’s points. The result, when designing gears and cutting tools using the proposed improved methods, assigns the curvilinear surface parametrically, represented by two-dimensional arrays characterizing its coordinates. To avoid interference at the design stage, it is necessary to analyze the intersection of the axis of the curvilinear generatrix with horizontal planes. That would make it possible, when machining an article, to avoid cutting, jamming, as well as the dangerous concentration of stresses. The accuracy and reliability of a wide range of articles in machines and machinery and other kinematic pairs also improve. The proposed improvement of circular and screw conversion methods to simulate curvilinear mated surfaces that exclude interference at the design stage is of practical interest in machine building

Sub-SMAS Transposition of the Buccal Fat Pad

BackgroundRegardless of the technique chosen to treat the aging midface, the isolated lateral approach facelift has a limited impact on the midface volume deficit. In an effort to overcome this limitation, modern facial rejuvenation procedures incorporate an additional modality for replenishing the midface volume. Some of the author’s facelift patients present with bulging buccal fat pads despite volume deficiency in the inframalar region. The author’s technique is designed to utilize the buccal fat pad to replenish the inframalar volume deficit.ObjectivesThe author sought to present the fat pad transposition surgical technique along with objective outcome data.MethodsThis study was a retrospective review of nonconsecutive cases where the sub-superficial-musculo-aponeurotic-system transposition of the buccal fat pad was performed. A total of 22 patients underwent the fat pad transposition technique by the author (O.B.) between July 2013 and December 2017. Patient data were obtained from patient records, 3-dimensional models, magnetic resonance images, and standardized photography. Preoperative differences in midface volume were assessed utilizing curvilinear surface measurements on 3-dimensional models and the Allergan midface volume deficit scale on standardized photography.ResultsThe average midface volume deficit score significantly improved, and the average midfacial curvilinear surface measurement significantly increased after surgery. Magnetic resonance imaging confirmed a stable position of the buccal fat pad after surgery.ConclusionsThe sub-superficial-musculo-aponeurotic-system transposition of the buccal fat pad is an effective technique that can be safely employed for autologous inframalar augmentation in patients with a favorable facial morphology.Level of Evidence: 4

A New Method of Distribution of Measurement Points on Curvilinear Surfaces of Products

The article presents the method of selecting scanning lines along which coordinate measurements, performed by using, e.g., a coordinate measuring machine working in the single point probing mode, of free-form surfaces of measured workpieces may be conducted. Additionally, the proposed method supports the user of a coordinate measuring system during defining the number of measurement points distributed along selected scanning lines, thus deciding on the final distribution of measurement points on a measured surface of a product. The proposed method enables distributing measurement points in the parts of a measured product characterized by the worst quality of manufacturing. Moreover, the new method is very automated, therefore it affects the increase in the efficiency of coordinate measurements. The effect of using the new method is the non-uniform distribution of measurement points located on free-form surfaces. The presented algorithm takes into account the lengths of selected cross-sections of a measured curvilinear surface of an object, its geometrical complexity and the accuracy of the probe radius correction process. The decision regarding the number of measurement points is made on the basis of the accuracy analysis of the calculations of the corrected measurement points obtained during the probe radius correction process and the accuracy of the substitute model representing a measured curvilinear surface. Two methods of the correction process were used. The accuracy of the applied methods of the probe radius compensation process was estimated on the basis of the deviations calculated between corrected measurement points and scanning lines. The selection of scanning lines and the number of measurement points was realized by using the expert system based on the fuzzy logic. The paper presents the results of both simulation and experimental investigations. The numerical calculations were performed for two selected free-form surfaces. The verification of the developed algorithm was carried out during experimental investigations based on a measurement of a selected free-form surface. The conducted research was aimed at verifying the correctness of the distribution of measurement points generated using the proposed method. In the case of real measurements, measurement points should be located in the places of surfaces of products characterized by the largest deviations of manufacturing. The results of the conducted investigations confirm the usefulness of the developed algorithm for defining the distribution of measurement points on curvilinear surfaces in the coordinate measuring technique. Moreover, the way of implementation of the developed method of the distribution of measurement points in selected commercial measurement software is presented, thus enabling the use of the new method in the industry.

Research and Method of Roughness Prediction of a Curvilinear Surface after Titanium Alloy Turning

This paper deals with the optimization of process parameters (such as cutting speed and feed rate) to minimize surface roughness in the turning of a titanium alloy (Ti-6Al-4V) workpiece with spherical shape. In the first part of the article, based on the results analysis, a mathematical model is developed. It is shown that cutting speed has little effect on the surface roughness. The second part of the paper presents the application of the developed method to optimize cutting data such as feed rate in order to obtain the surface roughness parameters Ra and Rz of the curvilinear surface of the titanium alloy workpiece at acceptable and aligned, values regardless of the surface shape and its tilted angle. A case study verifies the correctness of the proposed method. The machining time was substantially shortened in comparison to the non-optimized cutting process.

A shielded planar dielectric resonator with whispering gallery modes

The spectral and energy characteristics of two planar dielectric resonators (DRs), open and shielded from the curvilinear surface, excited in higher-order modes as whispering gallery modes (WGMs) in Ka-waveband are investigated. These resonators are formed by a thin (compared to the operating wavelength) disk dielectric structure, located between two conducting planes. Thus, the E-field of the resonator was limited along the height of the planar disk by two conducting surfaces. The resonance properties of such a structure are determined by the condition of total internal reflection of waves from the internal curvilinear surface of a dielectric disk. The carried out investigations shown that the unloaded Q-factor is increased at the arrangement of planar dielectric disk inside the ring metal shield at the certain ratio of the radiuses of the shield and dielectric disk. The Q-factor of the shielded resonant structure at the high-frequency edge increases to 40 %. The partial displacement of the resonant field of the WGMs modes from the dielectric to the air gap is the cause of this effect. It leads to decrease in losses in the dielectric material. A computer simulation of the WGMs fields in the planar DR was carried out using the CST Microwave Studio 2013 software to confirm this effect. In addition, computer simulation results shown that these WGMs in the planar DR are characterized by a homogeneous distribution of the resonant field along the axial coordinate. The perspectives of using planar DR in solid-state Ka-band oscillators are shown.

REPRESENTATION OF IRREGULAR SURFACES WITH THE HELP OF EQUIDISTANT LINES

Introduction. It must be proposed the method of geometric modeling surfaces тo represent and design non-regular surface surfaces. Purpose of the research is to offer a model of the reflection of irregular surfaces, which would contribute to making adjustments during the design. The aim The listed components of the problem must be solved simultaneously during the design process. It is necessary to propose a method that simultaneously takes into account several characteristics, for example, strength, aerodynamics, manufacturing simplicity, etc. Scientific novelty. We used following elements plane is defined as the curvilinear surface, the design rays are located at a variable angle with a two-parameter discrete dependency; the design center is located on the line (straight line or curve). The results. We receive equidistant lines on the rolled cylinder. The placement of the line with the design centers in space is determined by the complexity of the object. Such factors are solved with the presence of equations that reflect the changes in the surface with several parameters,. It was proposed to apply the method of geometric modeling surfaces тo represent and design non-regular surfaces. We use following elements plane is defined as the curvilinear surface, the design rays are located at a variable angle with a two-parameter discrete dependency; the design center is located on the line (straight line or curve). Conclusions. The proposed method of designing irregular surfaces makes it possible to simulate the necessary spatial changes by simple steps in the presence of a cylindrical reflection surface