Surface defect detection of machined parts based on machining texture direction
MEASUREMENT SCIENCE AND TECHNOLOGY
Authors: Lin, Jiangang; Wang, Dongxing; Tian, Hongzhi; Liu, Zhaocai
Abstract
Compared with detecting the regular texture of fabrics and prints, the detection of the processed texture on the surface of mechanical parts is more difficult. To quickly and accurately detect defects caused by abnormal machining of the surface of metal parts, a one-shot machine-vision method based on a texture orientation histogram is proposed. An improved Mean-C local threshold method is proposed to solve the problem of difficulty in extracting surface texture. Using the minimum enclosing rectangle, the skeleton texture is extracted from the enhanced image obtained by the improved Mean-C local threshold. The statistical information from the histogram is used to pre-process the texture direction, and then a novel angle region growth method proposed in this paper is used to search the main texture cluster and the abnormal texture cluster of the part, so as to realize the product quality detection. Experimental results show that this method is highly targeted for the detection of surface texture defects caused by abnormal processing, which is equivalent to the average performance of a multi-angle illumination detection system, but much faster. This detection method has high detection efficiency, high accuracy, and strong robustness, and can meet the requirements of industrial detection.
An effective method for improving the permeation flux of a ceramic membrane: Single-matrix spherical ceramic membrane
JOURNAL OF HAZARDOUS MATERIALS
Authors: Zhou, Wei; Zhang, Lin; Wu, Pute; Liu, Ying; Cai, Yaohui; Zhao, Xiao
Abstract
A single-matrix hydrophobic ceramic membrane (HCM) was prepared via gel-casting and membrane grafting. Fly ash cenospheres and 1H,1H,2H,2H-perfluorooctyl trichlorosilane were used as the single-matrix material. The results showed that when the sintering temperature was 1300 degrees C, the porosity was 75.56 %, and flexural strength was 11.1 MPa; this means that the material meets the requirements for mechanical properties. After grafting 1H,1H,2H,2H-perfluorooctane trichlorosilane, the Si -CH3 peak increased and the Si-OH peak was weaker. Also, the contact angle of the droplet increased from 56 degrees to 126 degrees, and this indicates that the droplet was successfully chemically adsorbed to the surface of the ceramic membrane. The results of computational fluid dynamics simulation show that a gaussian spherical wall greatly improved the permeation flux of foamed ceramic membranes, and the permeation flux of the microchannel increased by 26.5 % similar to 76.2 % at the same transmembrane pressure. Pure water permeation flux and heavy metal adsorption experiments shows excellent high permeation flux and satisfactory heavy metal adsorption performance of HCM. From the perspective of membrane cost, HCM is suitable to be promoted. In summary, HCM has the potential for commercial application.