为了提高工业产品表面缺陷的检测精度,提出了一种基于改进YOLOv5的表面缺陷检测方法。首先,结合MixUp、Mosaic和传统方法进行数据增强,修改YOLOv5残差单元,降低模型的浮点计算量;其次,将压缩激励(squeeze-and-excitation,SE)注意力机制...为了提高工业产品表面缺陷的检测精度,提出了一种基于改进YOLOv5的表面缺陷检测方法。首先,结合MixUp、Mosaic和传统方法进行数据增强,修改YOLOv5残差单元,降低模型的浮点计算量;其次,将压缩激励(squeeze-and-excitation,SE)注意力机制插入特征提取层末端和颈部首端,去除特征图中无用的背景干扰,提高对特征的提取效率;最后,在颈部末端,插入上下文变化(contextual transformer,CoT)模块,提高平均检测精度。使用改进的形状交并比非极大值抑制(shape-intersection over union non-maximum suppression,SIoU-NMS),剔除重复目标框。实验结果表明,在新材料地板缺陷数据集和瓶装白酒缺陷数据集上,所提算法的平均检测精度为81.2%和79.7%,较YOLOv5基线网络模型,分别提高了3.8%和4.6%,且优于其他典型的目标检测算法。这展现了该算法对工业产品表面缺陷进行识别和分类的精确性,可以更好地完成工业产品的质检过程。展开更多
Functionally graded material(FGM)can tailor properties of components such as wear resistance,corrosion resistance,and functionality to enhance the overall performance.The selective laser melting(SLM)additive manufactu...Functionally graded material(FGM)can tailor properties of components such as wear resistance,corrosion resistance,and functionality to enhance the overall performance.The selective laser melting(SLM)additive manufacturing highlights the capability in manufacturing FGMs with a high geometrical complexity and manufacture flexibility.In this work,the 316L/CuSn10/18Ni300/CoCr four-type materials FGMs were fabricated using SLM.The microstructure and properties of the FGMs were investigated to reveal the effects of SLM processing parameters on the defects.A large number of microcracks were found at the 316L/CuSn10 interface,which initiated from the fusion boundary of 316L region and extended along the building direction.The elastic modulus and nano-hardness in the 18Ni300/CoCr fusion zone decreased significantly,less than those in the 18Ni300 region or the CoCr region.The iron and copper elements were well diffused in the 316L/CuSn10 fusion zone,while elements in the CuSn10/18Ni300 and the 18Ni300/CoCr fusion zones showed significantly gradient transitions.Compared with other regions,the width of the CuSn10/18Ni300 interface and the CuSn10 region expand significantly.The mechanisms of materials fusion and crack generation at the 316L/CuSn10 interface were discussed.In addition,FGM structures without macro-crack were built by only altering the deposition subsequence of 316L and CuSn10,which provides a guide for the additive manufacturing of FGM structures.展开更多
The microstructure and texture of C/C composites with a resin-derived carbon, a rough laminar （RL） pyrocarbon and a smooth laminar pyrocarbon, before and after braking tests, were investigated by Raman spectroscopy....The microstructure and texture of C/C composites with a resin-derived carbon, a rough laminar （RL） pyrocarbon and a smooth laminar pyrocarbon, before and after braking tests, were investigated by Raman spectroscopy. The full width at half maximum （FWHM） of the D-band indicates the amount of defects in the in-plane lattice, while the G-to-D band intensity （peak area） ratios （lC/ID） is used to evaluate the degree of graphitization. The results show that the FWHM of D-band of sample with RL pyrocarbon changes greatly from 36 cm-1 to 168 cm 1 after braking tests, which indicates that a large number of lattice defects are produced on its wear surface. However, the graphitization degree of resin-derived carbon sample rises significantly, because the IC/1D increases from 0.427 to 0.928. Braking tests under normal loading conditions, involving high temperature and high pressure, produce a lot of lattice defects on the wear surface, and induce the graphitization of the surface. Sample with RL pyrocarbon having a low hardness is easy to deform, and has the most lattice defects on the wear surface after braking. While raw materials with resin-derived carbon have the lowest graphitization degree which rises greatly during braking.展开更多
文摘为了提高工业产品表面缺陷的检测精度,提出了一种基于改进YOLOv5的表面缺陷检测方法。首先,结合MixUp、Mosaic和传统方法进行数据增强,修改YOLOv5残差单元,降低模型的浮点计算量;其次,将压缩激励(squeeze-and-excitation,SE)注意力机制插入特征提取层末端和颈部首端,去除特征图中无用的背景干扰,提高对特征的提取效率;最后,在颈部末端,插入上下文变化(contextual transformer,CoT)模块,提高平均检测精度。使用改进的形状交并比非极大值抑制(shape-intersection over union non-maximum suppression,SIoU-NMS),剔除重复目标框。实验结果表明,在新材料地板缺陷数据集和瓶装白酒缺陷数据集上,所提算法的平均检测精度为81.2%和79.7%,较YOLOv5基线网络模型,分别提高了3.8%和4.6%,且优于其他典型的目标检测算法。这展现了该算法对工业产品表面缺陷进行识别和分类的精确性,可以更好地完成工业产品的质检过程。
基金Project(2020B090922002)supported by Guangdong Provincial Key Field Research and Development Program,ChinaProjects(51875215,52005189)supported by the National Natural Science Foundation of ChinaProject(2019B1515120094)supported by Guangdong Provincial Basic and Applied Basic Research Fund,China。
文摘Functionally graded material(FGM)can tailor properties of components such as wear resistance,corrosion resistance,and functionality to enhance the overall performance.The selective laser melting(SLM)additive manufacturing highlights the capability in manufacturing FGMs with a high geometrical complexity and manufacture flexibility.In this work,the 316L/CuSn10/18Ni300/CoCr four-type materials FGMs were fabricated using SLM.The microstructure and properties of the FGMs were investigated to reveal the effects of SLM processing parameters on the defects.A large number of microcracks were found at the 316L/CuSn10 interface,which initiated from the fusion boundary of 316L region and extended along the building direction.The elastic modulus and nano-hardness in the 18Ni300/CoCr fusion zone decreased significantly,less than those in the 18Ni300 region or the CoCr region.The iron and copper elements were well diffused in the 316L/CuSn10 fusion zone,while elements in the CuSn10/18Ni300 and the 18Ni300/CoCr fusion zones showed significantly gradient transitions.Compared with other regions,the width of the CuSn10/18Ni300 interface and the CuSn10 region expand significantly.The mechanisms of materials fusion and crack generation at the 316L/CuSn10 interface were discussed.In addition,FGM structures without macro-crack were built by only altering the deposition subsequence of 316L and CuSn10,which provides a guide for the additive manufacturing of FGM structures.
基金Project(2006CB600906) supported by the National Basic Research Program of China
文摘The microstructure and texture of C/C composites with a resin-derived carbon, a rough laminar （RL） pyrocarbon and a smooth laminar pyrocarbon, before and after braking tests, were investigated by Raman spectroscopy. The full width at half maximum （FWHM） of the D-band indicates the amount of defects in the in-plane lattice, while the G-to-D band intensity （peak area） ratios （lC/ID） is used to evaluate the degree of graphitization. The results show that the FWHM of D-band of sample with RL pyrocarbon changes greatly from 36 cm-1 to 168 cm 1 after braking tests, which indicates that a large number of lattice defects are produced on its wear surface. However, the graphitization degree of resin-derived carbon sample rises significantly, because the IC/1D increases from 0.427 to 0.928. Braking tests under normal loading conditions, involving high temperature and high pressure, produce a lot of lattice defects on the wear surface, and induce the graphitization of the surface. Sample with RL pyrocarbon having a low hardness is easy to deform, and has the most lattice defects on the wear surface after braking. While raw materials with resin-derived carbon have the lowest graphitization degree which rises greatly during braking.
