Surface topography analysis in three-dimensional elliptical vibration texturing (3D-EVT)

2019 ◽  
Vol 102 (5-8) ◽  
pp. 1601-1621 ◽  
Author(s):  
Rendi Kurniawan ◽  
Tae Jo Ko
2014 ◽  
Vol 490-491 ◽  
pp. 600-606
Author(s):  
Jie Qiong Lin ◽  
Jin Guo Han ◽  
Dan Jing ◽  
Xian Jing

Elliptical vibration cutting (EVC) process and three dimensional cutting surfaces are analyzed in this paper to understand the formation of surface topography. The model of EVC surface topography is established based on curved surface remove function under the assumption that the tool edge is sharp enough. And simulation analysis of surface topography is conducted with different feed offset ratios. Results indicate that RMS change with feed offset ratios λ. The range of RMS is larger when feed offset ratio ranges from both 0 to 0.4 and 0.6 to 1, while the range is smaller when feed offset ratio changes from 0.4 to 0.6. Whats more, RMS reaches the minimum when feed offset ratio is 0.5. The present research provides some references for reducing the height of vibration ripples and improving EVC surface quality.


2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Rendi Kurniawan ◽  
Saood Ali ◽  
Ki Moon Park ◽  
Sang Tae Jung ◽  
Tae Jo Ko

This paper presents our preliminary study of the microstructured surface on microgrooves patterns, which have manufactured using the three-dimensional elliptical vibration texturing (3D-EVT) method. The 3D-EVT method uses a three-dimensional trajectory of elliptical locus of the cutting tool tip in high vibration frequency to fabricate the microstructure or the vibration mark pattern on the machined surface. The experimental study has been done with a variation of the nominal cutting speeds from 300 to 600 mm/min. The preliminary results showed that in the low nominal cutting speed of 300 and 450 mm/min, the microstructured surfaces were not manufactured well due to the bulging existence on the microstructured surface in which it is correlated with the build-up edge phenomena. On the other hand, a relative excellent microstructured surface can be achieved at the higher nominal cutting speed of 600 mm/min. In addition, a lubricant could be used to obtain an excellent microstructured surface to avoid the built-up edge phenomena.


2014 ◽  
Vol 487 ◽  
pp. 479-483
Author(s):  
Jie Qiong Lin ◽  
Xian Jing ◽  
Tao Xu ◽  
Ming Ming Lu ◽  
Dan Jing

According to the surface formation mechanism of elliptical vibration cutting (EVC), EVC process and three dimensional cutting surfaces are analyzed in this paper. The model of EVC surface topography is established based on curved surface remove function under the assumption that the tool edge is sharp enough. Simulation analysis of surface topography is conducted to verify the established model. The present research clarifies the law that cutting parameters influent on EVC surface topography. Whats more, it provides some references for optimizing the selection of EVC cutting parameters and further improving EVC surface quality.


2020 ◽  
Vol 11 (1) ◽  
pp. 301
Author(s):  
Sławomir Paśko ◽  
Wojciech Glinkowski

Scoliosis is a three-dimensional trunk and spinal deformity. Patient evaluation is essential for the decision-making process and determines the selection of specific and adequate treatment. The diagnosis requires a radiological evaluation that exposes patients to radiation. This exposure reaches hazardous levels when numerous, repetitive radiographic studies are required for diagnostics, monitoring, and treatment. Technological improvements in radiographic devices have significantly reduced radiation exposure, but the risk for patients remains. Optical three-dimensional surface topography (3D ST) measurement systems that use surface topography (ST) to screen, diagnose, and monitor scoliosis are safer alternatives to radiography. The study aimed to show that the combination of plain X-ray and 3D ST scans allows for an approximate presentation of the vertebral column spinous processes line in space to determine the shape of the spine’s deformity in scoliosis patients. Twelve patients diagnosed with scoliosis, aged 13.1 ± 4.5 years (range: 9 to 20 years) (mean: Cobb angle 17.8°, SD: ±9.5°) were enrolled in the study. Patients were diagnosed using full-spine X-ray and whole torso 3D ST. The novel three-dimensional assessment of the spinous process lines by merging 3D ST and X-ray data in patients with scoliosis was implemented. The method’s expected uncertainty is less than 5 mm, which is better than the norm for a standard measurement tool. The presented accuracy level is considered adequate; the proposed solution is accurate enough to monitor the changes in the shape of scoliosis’s spinous processes line. The proposed method allows for a relatively precise calculation of the spinous process lines based on a three-dimensional point cloud obtained with a four-directional, three-dimensional structured light diagnostic system and a single X-ray image. The method may help reduce patients’ total radiation exposure and avoid one X-ray in the sagittal projection if biplanar radiograms are required for reconstructing the three-dimensional line of the spinous processes line.


Wear ◽  
2007 ◽  
Vol 262 (3-4) ◽  
pp. 395-410 ◽  
Author(s):  
N. Senin ◽  
M. Ziliotti ◽  
R. Groppetti

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 78 ◽  
Author(s):  
Gregory de Boer ◽  
Andreas Almqvist

A two-scale method for modelling the Elastohydrodynamic Lubrication (EHL) of tilted-pad bearings is derived and a range of solutions are presented. The method is developed from previous publications and is based on the Heterogeneous Multiscale Methods (HMM). It facilitates, by means of homogenization, incorporating the effects of surface topography in the analysis of tilted-pad bearings. New to this article is the investigation of three-dimensional bearings, including the effects of both ideal and real surface topographies, micro-cavitation, and the metamodeling procedure used in coupling the problem scales. Solutions for smooth bearing surfaces, and under pure hydrodynamic operating conditions, obtained with the present two-scale EHL model, demonstrate equivalence to those obtained from well-established homogenization methods. Solutions obtained for elastohydrodynamic operating conditions, show a dependency of the solution to the pad thickness and load capacity of the bearing. More precisely, the response for the real surface topography was found to be stiffer in comparison to the ideal. Micro-scale results demonstrate periodicity of the flow and surface topography and this is consistent with the requirements of the HMM. The means of selecting micro-scale simulations based on intermediate macro-scale solutions, in the metamodeling approach, was developed for larger dimensionality and subsequent calibration. An analysis of the present metamodeling approach indicates improved performance in comparison to previous studies.


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