On-line measurement of manufaturing quality of rolled steel needs the performances of noncontact, high-responds, high-resolution and high aceuracy. The reccntly developed hardware makes it possible. This paper gives a...On-line measurement of manufaturing quality of rolled steel needs the performances of noncontact, high-responds, high-resolution and high aceuracy. The reccntly developed hardware makes it possible. This paper gives a review of the development of this techniques and introduces four kinds of developed measurement systems. And the future development trends in this field was also discussed.展开更多
The laser powder bed fusion(L-PBF)method of additive manufacturing(AM)is increasingly used in various industrial manufacturing fields due to its high material utilization and design freedom of parts.However,the parts ...The laser powder bed fusion(L-PBF)method of additive manufacturing(AM)is increasingly used in various industrial manufacturing fields due to its high material utilization and design freedom of parts.However,the parts produced by L-PBF usually contain such defects as crack and porosity because of the technological characteristics of L-PBF,which affect the quality of the product.Laser ultrasonic testing(LUT)is a potential technology for on-line testing of the L-PBF process.It is a non-contact and non-destructive approach based on signals from abundant waveforms with a wide frequency-band.In this study,a method of LUT for on-line inspection of L-PBF process was proposed,and a system of LUT was established approaching the actual environment of on-line detection to evaluate the method applicability for defects detection of L-PBF parts.The detection results of near-surface defects in L-PBF 316L stainless steel parts show that the crack-type defects with a sub-millimeter level within 0.5 mm depth can be identified,and accordingly,the positions and dimensions information can be acquired.The results were verified by X-ray computed tomography,which indicates that the present method exhibits great potential for on-line inspection of AM processes.展开更多
Manufacturing accuracy, especially position accuracy of fastener holes, directly affects service life and security of aircraft. The traditional modification has poor robustness, while the modification based on laser t...Manufacturing accuracy, especially position accuracy of fastener holes, directly affects service life and security of aircraft. The traditional modification has poor robustness, while the modification based on laser tracker costs too much. To improve the relative position accuracy of aircraft assembly drilling, and ensure the hole-edge distance requirement, a method was presented to modify the coordinates of drilling holes. Based on online inspecting two positions of pre-assembly holes and their theoretical coordinates, the spatial coordinate transformation matrix of modification could be calculated. Thus the straight drilling holes could be modified. The method improves relative position accuracy of drilling on simple structure effectively. And it reduces the requirement of absolute position accuracy and the cost of position modification. And the process technician also can use this method to decide the position accuracy of different pre-assembly holes based on the accuracy requirement of assembly holes.展开更多
A model recognition method for the on-line optimal control of the parameters ofthree-cone blast drills is developed. It takes a few of on-line measurements and has a rapidoptimization speed. The mathematic model for o...A model recognition method for the on-line optimal control of the parameters ofthree-cone blast drills is developed. It takes a few of on-line measurements and has a rapidoptimization speed. The mathematic model for on-line optimal control of the parameters and thedetermination of the parameters in the model are also presented.展开更多
In a high thrust-weight-ratio aero-engine,turbine blades are exposed to extremely high temperature and pressure which sets higher demands in the blade cooling technology.To boost film-cooling effectiveness,an accurate...In a high thrust-weight-ratio aero-engine,turbine blades are exposed to extremely high temperature and pressure which sets higher demands in the blade cooling technology.To boost film-cooling effectiveness,an accurate,efficient,and all-sided inspection of film cooling holes is urgently requested to ensure the quality of turbine blades.The tiny size of film-cooling holes adds to extreme difficulties in the inspection process both by contact and non-contact measurement.This paper proposed a non-contact measuring technique to cope with the inspection of turbine blades.A specially designed light-field camera with a small field of view and proper depth of field is applied to resolve a 3D geometry of film cooling holes.The technique uses one light field camera to capture images of the blade surface.3D lightfield reconstruction algoritm is applied and point cloud of the blade is generated.Due to the compactness of the non-contact single light-field imaging system,information inside the holes becomes attainable.By precisely controlling the relative pose of the camera to the blade surface,the device can obtain hole diamter and outlet angle with an accuracy of±0.03mm and±1°17’respectively.The average time consumed for reconstructing one film cooling hole is about 5 seconds.展开更多
文摘On-line measurement of manufaturing quality of rolled steel needs the performances of noncontact, high-responds, high-resolution and high aceuracy. The reccntly developed hardware makes it possible. This paper gives a review of the development of this techniques and introduces four kinds of developed measurement systems. And the future development trends in this field was also discussed.
基金the National Key R&D Program of China(Grant No.2018YFB1106100)。
文摘The laser powder bed fusion(L-PBF)method of additive manufacturing(AM)is increasingly used in various industrial manufacturing fields due to its high material utilization and design freedom of parts.However,the parts produced by L-PBF usually contain such defects as crack and porosity because of the technological characteristics of L-PBF,which affect the quality of the product.Laser ultrasonic testing(LUT)is a potential technology for on-line testing of the L-PBF process.It is a non-contact and non-destructive approach based on signals from abundant waveforms with a wide frequency-band.In this study,a method of LUT for on-line inspection of L-PBF process was proposed,and a system of LUT was established approaching the actual environment of on-line detection to evaluate the method applicability for defects detection of L-PBF parts.The detection results of near-surface defects in L-PBF 316L stainless steel parts show that the crack-type defects with a sub-millimeter level within 0.5 mm depth can be identified,and accordingly,the positions and dimensions information can be acquired.The results were verified by X-ray computed tomography,which indicates that the present method exhibits great potential for on-line inspection of AM processes.
文摘Manufacturing accuracy, especially position accuracy of fastener holes, directly affects service life and security of aircraft. The traditional modification has poor robustness, while the modification based on laser tracker costs too much. To improve the relative position accuracy of aircraft assembly drilling, and ensure the hole-edge distance requirement, a method was presented to modify the coordinates of drilling holes. Based on online inspecting two positions of pre-assembly holes and their theoretical coordinates, the spatial coordinate transformation matrix of modification could be calculated. Thus the straight drilling holes could be modified. The method improves relative position accuracy of drilling on simple structure effectively. And it reduces the requirement of absolute position accuracy and the cost of position modification. And the process technician also can use this method to decide the position accuracy of different pre-assembly holes based on the accuracy requirement of assembly holes.
文摘A model recognition method for the on-line optimal control of the parameters ofthree-cone blast drills is developed. It takes a few of on-line measurements and has a rapidoptimization speed. The mathematic model for on-line optimal control of the parameters and thedetermination of the parameters in the model are also presented.
基金Aero Engine Corporation of China(HFZL2020CXY014-1,HFZL2020CXY014-2)。
文摘In a high thrust-weight-ratio aero-engine,turbine blades are exposed to extremely high temperature and pressure which sets higher demands in the blade cooling technology.To boost film-cooling effectiveness,an accurate,efficient,and all-sided inspection of film cooling holes is urgently requested to ensure the quality of turbine blades.The tiny size of film-cooling holes adds to extreme difficulties in the inspection process both by contact and non-contact measurement.This paper proposed a non-contact measuring technique to cope with the inspection of turbine blades.A specially designed light-field camera with a small field of view and proper depth of field is applied to resolve a 3D geometry of film cooling holes.The technique uses one light field camera to capture images of the blade surface.3D lightfield reconstruction algoritm is applied and point cloud of the blade is generated.Due to the compactness of the non-contact single light-field imaging system,information inside the holes becomes attainable.By precisely controlling the relative pose of the camera to the blade surface,the device can obtain hole diamter and outlet angle with an accuracy of±0.03mm and±1°17’respectively.The average time consumed for reconstructing one film cooling hole is about 5 seconds.
