The mathematical beveloid gear tooth surface model considering machine tool adjustment errors was derived. The definition and calculation process of tooth surface deviations along the tooth trace and profile directions for beveloid gear were proposed. Also, the solid model and the finite element mesh model of a paralleled beveloid gear pair were developed. Then, the effects of the machine tool adjustment errors including independent helix angle error, independent cone angle error and combined helix and cone angle errors on tooth surface deviation and contact characteristics were investigated. Results show that all the machine tool adjustment errors cause an incremental trend for the tooth profile and tooth trace deviations. And positive errors have the opposite impact on the surface deviation compared with the negative errors. The independent helix angle error has a stronger impact on the tooth surface deviations than the independent cone angle error and combined angle errors. Also, the tooth surface deviations caused by the independent helix angle error, independent cone angle error and combined angle errors have the similar magnitude level as the tooth surface modifications. All the independent helix angle error, independent cone angle error and combined angle errors tend to have deteriorative effects on the mesh characteristics, making edge contact worse, decreasing the contact area, increasing the contact pressure and the transmission error. The independent helix angle error has the strongest impact both on the contact pattern and transmission error, which is similar to the impact on the tooth surface deviations. However, the independent cone angle error shows less effects on the mesh characteristics. Thus the machine tool adjustment errors should be strictly controlled especially for the helix angle error during manufacturing.

As a kind of efficient and rapid developed surface processing technique, polishing technology is widely used to improve the surface quality in the precision manufacturing of aero-engine blisk blades. Since blisk blade polishing is a metal removal process which aims to produce smooth surfaces with very low surface roughness, it is difficult to achieve the optimum balance between high material removal rate and low surface roughness. To solve this problem, this study investigates the process parameter optimization to improve the material removal rate with high surface quality in the belt flapwheel polishing of TC4 aero-engine blisk blades. The experiment was designed by Box-Behnken design (BBD) theory of response surface methodology. Then the prediction model of material removal rate was built based on the linear regression analysis of experimental data. To improve material removal rate on the condition that surface roughness meets technical requirements, the single-objective constrained optimization problem was solved utilizing the Particle Swarm Optimization (PSO) technique. Finally, the feasibility of this method was experimentally verified. This study provides a theoretical and experimental reference for the evaluation and improvement of material removal rate with good surface quality in TC4 blisk blade polishing process.

Mesh denoising is crucial for improving imperfect mesh models corrupted with raw or synthetic noise. The main technical challenge of mesh denoising is to faithfully retain geometric features when removing noise. Nevertheless, most of the existing approaches are not suitable for large-scale noise, overlook some geometric features, and often need carefully select appropriate parameter values to achieve a good result. In this paper, we present effective collaborative filters for mesh denoising based on vertex classification. The effectiveness of our method stems from several aspects: 1) Global preprocessing is performed to drastically reduce noise influences. 2) Normal tensor voting is utilized to classify the vertices, so that we can select different filters to estimate the face normals according to the detected type of vertices. Our method adaptively prevents the side effects from facets with high geometrical disparity in the feature region, which avoids the subjective selection of parameter values to achieve the local optimum, and removes outliers in the non-feature region. 3) Normal difference weights are introduced to vertex updating. Benefited from the well-designed filters on different types of vertices, our algorithm produces visually and numerically better denoising results than the existing typical approaches for both CAD and generic models corrupted by high level of noises, especially at sharp features, such as edges and corners

Affected by high temperature and pressure during the process of cutting stainless steel, the affinity element diffusion of tool-chips leads to the appearance of adhesion on the rake face, which eventually results in adhesion failure of the tool. In this study, we determined the formation of tool-chip adhesion during the cutting process using a cutting test; and put forward an experimental scheme of the element diffusion for clamped and welded specimens of the tool and workpiece. Fick's second law was used to develop a theoretical model of element diffusion to analyze the effect of tool-chip adhesion on the Fe and W element diffusion coefficient of Fe and W. The hardness of the tool surface was measured and analyzed after the diffusion experiment. The results showed that the tool-chip adhesion on the rake face of the tool was similar to pressure diffusion welding and that the tool-chip adhesion on the rake face directly affected the diffusion concentration of W, but had little effect on the diffusion concentration of Fe. In addition, the diffusion coefficient of Fe or W in the tool-chip adhesion is always greater for stick-welding than for non-stick-welding. The research results are of great significance for improving the cutting performance and tool life.

Recently medical treatment device using a complex vibration is developed, it has been designed for the improvement of the conversion efficiency. However, few reports are available on the vibration transducers as used in small blood vessel. In this paper, the new type longitudinal-torsional complex vibration transducer was designed. The principle of vibration conversion from longitudinal vibration to longitudinal-torsional complex vibration was described in detail. In order to obtain the most effective performance, the structure parameters of the vibrator involving the mode conversion were mentioned. The important parameters to achieve the highest conversion efficiency from longitudinal vibration to torsional vibration were investigated by using the finite element method analysis models. The angled-multilayered converter was designed, and the important parameters as layers offset angle and lead angle of twist structure were discovered. The most effective parameters were obtained for the offset angle was 10 degree and the lead angle was 56-59 degree. It was confirmed that the vibration conversion efficiency was improved by making a hole for the suction into the device.

Aiming at the problem in obtaining the precise failure rates of components, this paper presents a new reliability evaluation method for complex systems using interval triangular fuzzy subset and evidence network (EN). Specifically, it develops the fault tree model based on failure mode and effects analysis (FMEA) and uses the interval-valued triangular fuzzy weighted mean to express the interval failure rates of components. Furthermore, fuzzy fault tree is mapped into an EN to calculate some reliability parameters. In addition, a possibility-based NSG ranking approach is adopted to rank components and get the critical component, which can be used to provide the basis for system optimization and maintenance decision-making. Finally, a numerical example is given to validate the availability and efficiency of the proposed method.

Lubricating oils are used in various machines and devices; however, they degrade during operation because of their usage environment. The causes of lubricating oil contamination are roughly classified into two types: the contamination caused by solid particles and that caused by oil oxidation products. Much research into diagnosing solid particles in lubricating oils has been conducted and many standards have been achieved; however, few diagnosis methods exist for oil oxidation products. Moreover, the oxidation of turbine basis oils has recently become a serious problem in power generation plants. Therefore, an on-site deterioration diagnosis method capable of detecting turbine oil oxidation in its early stages is desirable for proactive maintenance. We have developed a lubricating oil contamination diagnosis method that considers the coloration of contaminated membrane patches. Sample oils for testing the method have been oxidized in a laboratory using a rotary pressure vessel oxidation test apparatus, and the colors of the resulting membrane patches have been determined using the colorimetric patch analyzer. The relation between the colors and the Fourier transform infrared spectroscopy analysis has been investigated. The results verify that the proposed method is capable of an early detection of changes in the oxidation products of turbine oil.

The present paper describes a new non-axisymmetric curved surface turning (NACS-Turning) method. Fast tool servo (FTS) technology has been widely researched and developed. However, the movable range of the FTS is limited to a few millimeters owing to its mechanism. Therefore, in the present study, we describe the development of a new NACS-Turning method that can realize long stroke and high bandwidth in the cutting direction (X-axis) of the turning tool by using a linear motor. We confirmed that NACS-Turning could machine a non-axisymmetric workpiece while the X-axis slide was synchronized at an acceleration of 4.5 g with a spindle rotation of 750 min^-1. However, in this machining method, the machining accuracy deteriorates depending on the acceleration and cutting reaction force of the X-axis slide. In particular, excess from the designed allowable acceleration threatens to cause a serious machining error. Therefore, the present paper describes the possibility of machining considering the acceleration and improvement of machining accuracy in NACS-Turning. We examine the relationships between machining parameters and the accelerations as well as the tool path generation method considering these relationships. Moreover, machining accuracy is improved by on-machine measurement. We constructed a system whereby a re-machining tool path is generated by measuring the profile of the machined workpiece and feeding the measurement results back to the CAM. As a result, we obtained a theorem for the possibility of machining via NACS-Turning and confirmed the improvement in accuracy.

Cutting teeth of a dual-cone double enveloping hourglass worm wheel hob retain land surfaces with a certain width to increase the service life of the hob because this kind of hob cannot be re-sharpened. The land widths from the top to the root of all of the cutting teeth should be uniform so that all of them have the same cutting performance. However, the accuracy and the uniformity of the land width of the land surface of hob with spiral rake faces have not been studied till now. To solve this problem, this paper puts forward a method for designing the land surfaces of the hob with spiral rake faces and studies the accuracy and the uniformity. The spiral rake faces of the teeth of the hob are generated by a cylindrical surface. The offset surfaces of the spiral rake faces are obtained by offsetting the spiral rake faces along their normal vector directions with the offsetting distance equal to the land width. The rake faces and the offsetting surfaces intersect with the helical surfaces so the cutting edges and the land edges can be gotten, respectively. The land width of each cutting tooth is the distance between its cutting edge and its land edge. The results of a numerical example show that the calculated land widths on the pitch torus decrease firstly and then increase from one end to another end along the axial direction. The difference of the calculated land widths between the top and the root is larger at side teeth than that at middle teeth. The calculated land widths are slightly larger than the given one and all the calculated land widths change within a small range that can be ignored. Therefore, the method can keep the accuracy and the uniformity.

The paper presents a panel-based robotic mannequin for garment fitting. This robot can deform the shell panels and change their positions to simulate different consumers’ body shapes. Then it will replace consumers to try on the clothes remotely, so as to avoid the troubles caused by geographical location. This paper mainly introduces the structural design and optimization of a new fitting robot, which comprises the optimization of the shell panels, the design of the mechanical structure, and the optimization of the control system. Furthermore, to obtain the fitting results of different body postures, we design a detachable arm structure. Based on the above work, we develop a new prototype of the female robotic mannequin. The testing results show that the accuracy of the deformation and the stability of the whole structure are improved. The fitting robot can accurately simulate most of the female human bodies and smoothly complete the remote fitting process. It can be applied to garment e-commerce, personalized customization and virtual fitting.

For the safety problems caused by abnormal changes of stress-time history at fatigue risk points of casting crane metal structure due to the vertical impact effect of track defects, the forecast method of fatigue residual life of casting crane under track defect model is proposed. Guided by the kinematics and dynamics theory, the kinematic-dynamic model of dynamic load resulted from crane travelling on defective track including the high-low dislocation and horizontal gap is established. The influence of track defects on the vertical impact effect of operation crane is analyzed. Furthermore, combining with the collection of technological process and usage of casting crane, the characteristic parameters needed in the process of stress spectrum acquisition are determined. The allowable stress method combined with finite element simulation is used to get the fatigue risk cross-sections and points of crane metal structure and the first principal stress-time histories of dangerous points are obtained. The double parameter stress spectrum of dangerous points is extracted by rain flow technology. Based on fracture mechanics and damage tolerance design, the fatigue residual life of dangerous points is estimated by Paris formula. Taking the 100/40t-28.5m casting crane as an example, the feasibility of the above model and method is verified.

This study proposed a new method to automatically determine cutting conditions for NC program generation by utilizing the similarity of the removal volume extracted from a work material. In the new method, the cutting conditions associated with the geometric properties of the removal volume, which is extracted from work material shape and product shape, are stored in database as a machining case data. The most similar machining case data from the database can be selected according to the properties of the removal volume and the cutting conditions associated with the removal volume are reused. The proposed method can select the most similar machining case data from the database even for the complicated product shape, because each removal volume extracted by the proposed method is geometrically simple. In the case study for the validation of the proposed method, the cutting conditions, which is associated with the most similar geometric properties of removal volume from the database, were successfully determined. Furthermore, an NC program was automatically generated appropriately. The machining experiment using the generated NC program could be completed without any trouble.

In this work optimization of turning parameters for turning Ti-6Al-7Nb Titanium alloy has been investigated by orthogonal array along with Grey relational analysis coupled with principle component. Parameters such as surface roughness, tool wear, roundness, material removal rate, temperature and power consumption are considered as performance characteristics of the turning process. By orthogonal array eighteen experiments are carried out in the CNC machine by considering cutting environment, cutting speed, feed rate, depth of cut, nose radius, tool coating type and insert shape angle as turning parameters. From the grey relational grade the optimum turning parameters were predicted. Also the influence of individual turning parameters is carried out by Analysis of Variance. From the largest value of grey relational grade parameters , cutting environment: wet, feed rate : 0.08 mm /rev, cutting speed: 100 m/min ,insert angle: 80⁰, nose radius: 0.4 mm, tool coating type : TiAlN and depth of cut:0.4 mm are found to be better turning parameters levels. About 11.3 % enhancement of grey relation grade value is achieved when compared to initial parameter grey relational grade value.