The Experts below are selected from a list of 34245 Experts worldwide ranked by ideXlab platform
Han Lin Liao - One of the best experts on this subject based on the ideXlab platform.
-
a spherical surface Coating thickness model for a robotized thermal spray system
Robotics and Computer-integrated Manufacturing, 2019Co-Authors: Yanjun Zhang, Han Lin Liao, Wenbo Li, Chao Zhang, Yicha Zhang, Sihao DengAbstract:Abstract Coating thickness prediction is critical for robotic thermal spray system's tool-path planning. Current prediction models could not give accurate estimation for a type of important spherical Coating surfaces in industrial application. To facilitate tool-path generation and improve the Coating Quality for this special surface shape, this paper proposes a new analytical thickness prediction model. Both numerical simulation and experimental testing are conducted. The results reveal that the model is flexible and efficient to predict the Coating thickness and uniformity in acceptable tolerance and expedient to predict the Coating thickness on non-holonomic spherical surfaces. It could be used for automatic tool-path generation for the robotic thermal spray system.
-
effects of substrate heat accumulation on the cold sprayed ni Coating Quality microstructure evolution and tribological performance
Surface & Coatings Technology, 2019Co-Authors: Sihao Deng, Chaoyue Chen, Yingchun Xie, Xinliang Xie, Xingchen Yan, Renzhong Huang, Jiang Wang, Zhongming Ren, Han Lin LiaoAbstract:Abstract The residual stress and distortion caused by non-uniform temperature distribution has limited the application of cold spray (CS) technique as an effective additive manufacturing and damage repair method for large-scale components. In order to investigate the influence of heat accumulation on Coating Quality, two types of CS Ni Coatings with different building dimensions were deposited onto substrates. The type II Ni Coatings with smaller fabrication size possess a fully dense microstructure without cracks, while the type I Coatings with larger size show a significantly higher porosity value. The type II Coatings show relatively higher microhardness. The tribological tests show that the type II Ni Coatings present a better wear resistance with lower coefficient of friction and lower wear rate. The distinct worn morphologies show that the lower microhardness and porous microstructure of type I Coatings lead to numerous delamination and exposure of interior Coating. According to the temperature history recorded by infrared imaging camera, higher average temperature was found at the type II Coatings due to enhanced heat accumulation of Coating/substrate system at the short nozzle movement. The increased particle plastic deformation can further promote the Coating densification rate and further ameliorate the Coating Quality. It can be summarized that the nozzle trajectory and deposition strategy can affect the temperature distribution and determine the Coating qualities. This work provides a potential guidance for the optimization of Coating Quality by cold spraying additive manufacturing.
-
the effect of spray distance and scanning step on the Coating thickness uniformity in cold spray process
Journal of Thermal Spray Technology, 2014Co-Authors: Zhenhua Cai, Han Lin Liao, Sihao Deng, Chunnian Zeng, Ghislain MontavonAbstract:In the process of cold spray applications, robot kinematic parameters represent significant influences on the Coating Quality. Those parameters include: spray distance, spray angle, gun relative velocity to substrate, scanning step, and cycle numbers. The combined effects which are caused by their interactions determine the Coating thickness. The increasing requirements of Coating productivity lead to the objectivity of analyzing the effect of robot kinematic parameters. So it becomes necessary to optimize the robot trajectory for spraying process in order to obtain a desired Coating thickness. This study aims at investigating the relationship between the Coating profile and the spray distance, scanning step, and introducing the basic principle of a software toolkit named thermal spray toolkit (TST) developed in our laboratory to generate the optimized robot trajectories in spray processes including thermal spray and cold spray. Experiments have been carried out to check the reliability of the simulated Coating profile and the calculated Coating thickness by TST.
-
deformation behavior of the oxide film on the surface of cold sprayed powder particle
Applied Surface Science, 2012Co-Authors: Han Lin Liao, Shuo Yin, Xiaofang Wang, Hongen JieAbstract:Abstract In cold spraying, oxide-free interface is an important factor for metal-to-metal contact between powder particles and substrate, which determines the bonding strength and final Coating Quality. In this study, a systematic finite element analysis (FEA) is performed to examine the deformation behavior of the oxide film on an Al 6061-T6 particle surface after deposition. The simulation results show that the oxide film can be disrupted during the high velocity impact. Part of the cracked oxides remains at the interface and mainly accumulates at the central region after particle deposition. Substrate hardness, particle velocity and spray angle are found to influence the deformation behavior and final state of the oxide film. Besides, interparticle interaction is also investigated in the present work to clarify the deformation behavior of the oxide film inside the Coating.
-
application of robot offline programming in thermal spraying
Surface & Coatings Technology, 2012Co-Authors: Sihao Deng, Han Lin Liao, Zhenhua Cai, Dandan Fang, Ghislain MontavonAbstract:Abstract Nowadays, robot manipulators have already been widely used in thermal spraying. They can be programmed in two ways: online and offline programming. The first programming method is easy to operate but difficult to guarantee the Quality of Coatings, especially for some complex workpieces. The offline programming technology is a good solution that can overcome the online programming tolerances by using the CAD files of the workpiece. The purpose of this study is to introduce the current applications of offline programming technology in thermal spraying, including some popular methods of path generation, process simulation, robot kinematics optimization, etc. In the last part of this paper, two examples of offline programming in thermal spraying were presented which refer to the trajectory optimization on a workpiece with a great angle and path generation on the complex workpiece with external axis. The simulations and experiments have proved that offline programming can effectively improve the production efficiency and Coating Quality.
Miriam Haase - One of the best experts on this subject based on the ideXlab platform.
-
evaluating the effect of Coating equipment on tablet film Quality using terahertz pulsed imaging
European Journal of Pharmaceutics and Biopharmaceutics, 2013Co-Authors: Miriam Haase, Kaisa Naelapaa, Keith C Gordo, M Peppe, Jukka Rantane, Clare J StrachaAbstract:Abstract In this study, terahertz pulsed imaging (TPI) was employed to investigate the effect of the Coating equipment (fluid bed and drum coater) on the structure of the applied film Coating and subsequent dissolution behaviour. Six tablets from every batch coated with the same delayed release Coating formulation under recommended process conditions (provided by the Coating polymer supplier) were mapped individually to evaluate the effect of Coating device on critical Coating characteristics (Coating thickness, surface morphology and density). Although the traditional Coating Quality parameter (weight gain) indicated no differences between both batches, TPI analysis revealed a lower mean Coating thickness (CT) for tablets coated in the drum coater compared to fluid bed coated tablets (p
Clare J Stracha - One of the best experts on this subject based on the ideXlab platform.
-
evaluating the effect of Coating equipment on tablet film Quality using terahertz pulsed imaging
European Journal of Pharmaceutics and Biopharmaceutics, 2013Co-Authors: Miriam Haase, Kaisa Naelapaa, Keith C Gordo, M Peppe, Jukka Rantane, Clare J StrachaAbstract:Abstract In this study, terahertz pulsed imaging (TPI) was employed to investigate the effect of the Coating equipment (fluid bed and drum coater) on the structure of the applied film Coating and subsequent dissolution behaviour. Six tablets from every batch coated with the same delayed release Coating formulation under recommended process conditions (provided by the Coating polymer supplier) were mapped individually to evaluate the effect of Coating device on critical Coating characteristics (Coating thickness, surface morphology and density). Although the traditional Coating Quality parameter (weight gain) indicated no differences between both batches, TPI analysis revealed a lower mean Coating thickness (CT) for tablets coated in the drum coater compared to fluid bed coated tablets (p
Christian Coddet - One of the best experts on this subject based on the ideXlab platform.
-
effect of dry ice blasting on the microstructure and properties of plasma sprayed conicraly Coating
Materials Science Forum, 2013Co-Authors: Shujuan Dong, BERNARD HANSZ, Bo Song, Christian CoddetAbstract:Depending on the oxidation extent and the surface roughness after Coating manufacturing, CoNiCrAlY Coating displays different performance in thermal barrier Coating systems. In this study, plasma-sprayed CoNiCrAlY Coatings were treated by dry-ice blasting. Various treatment approaches of dry-ice blasting were assessed by means of comparing the Coating Quality in terms of cross-sectional structure, oxide concentration, surface morphology and roughness, and microhardness. The results showed that CoNiCrAlY Coating including decreased oxides and smoother internal texture can be obtained in comparison with that deposited by conventional APS, no matter what type of treatment. The oxidation content differ after using different jet angle and installation location of dry-ice blasting. To some extent, dry-ice blasting has some cleaning effect on those splashed particles. However, no much change can be recognized in the top-surface morpholgy and surface roughness, because of the relatively small hardness of dry-ice pellets. There is a slight decrease in hardness probably resulting from the decrease in the oxide.
-
the effect of robot kinematics on the Coating thickness uniformity
Journal of Thermal Spray Technology, 2010Co-Authors: D Fang, Han Lin Liao, Sihao Deng, Christian CoddetAbstract:The torch speed is one of the most important operating parameters in thermal spraying. Generally, in order to keep a uniform Coating thickness, the movement of the torch should be constant. Nevertheless, when the torch follows a large trajectory angle, the torch speed will decrease significantly, which leads to an irregular Coating thickness. This phenomenon is caused by the weight of different devices fixed on the robot and the combination of the robot’s six axes. It is therefore necessary to optimize robot kinematics behaviors in this case. In this paper, the works concentrate mainly on the relationship between the robot kinematics property and the Coating Quality to find an adequate model for the torch speed optimization. An add-in program based on RobotStudio™ (ABB, Sweden) is developed to determine and optimize the spray trajectory. The optimal trajectory was verified by both the simulations and the experiments.
-
relationships between nicrbsi particle characteristics and corresponding Coating properties using different thermal spraying processes
Surface & Coatings Technology, 2005Co-Authors: Marie-pierre Planche, Han Lin Liao, Bernard Normand, Christian CoddetAbstract:Because the microstructure and physical properties of a thermally sprayed Coating are determined by the dynamics of the particles interacting with the spray jet, different processes were tested in order to explore the effects of process variables to particle characteristics and to Coating Quality. The NiCrBSi powder was sprayed successively with plasma, flame and HVOF process. Standard parameters specified by previous researches were followed for this operation. The DPV 2000 measurement system was used to monitor particle characteristics during their flight into the spray. Then, the Coatings were realized at the position corresponding to the DPV measurements. The Coatings were characterized in term of microstructure and composition, hardness, Young modulus, porosity and oxide level. The results revealed significant modifications in Coating properties depending on the used spray process. Comparing the particle characteristics obtained successively with the different processes allows to better understand the properties of the formed Coatings and to investigate the causes of a Coating Quality changes. Differences were interpreted based on in-flight diagnostic results.
-
designing expert system using neural computation in view of the control of plasma spray processes
Materials & Design, 2003Co-Authors: Sofiane Guessasma, Patrick Gougeon, Ghislain Montavon, Christian CoddetAbstract:Abstract This paper aims at integrating the artificial intelligence methodologies in a Quality control of ceramic Coating fabrication using the atmospheric plasma spray (APS) process. In such a way, the average velocity, temperature and diameter of thermally sprayed Al 2 O 3 -13 wt.% TiO 2 particles before impinging the work piece and forming a deposit are monitored. Then, as these particle characteristics represent the most pertinent indicators of the Coating properties and characteristics reproducibility, they are chosen as the output of an expert system based on neural computation. The model is built also considering at the system input the plasma and particle powder injection-processing parameters. After an optimisation procedure, the predicted results are compared to the results of experimental data resulting from a non-intrusive sensor conventionally used by industrials to control the Coating Quality. The good agreement found between these results permits to establish the overall effect of each processing parameter on the in-flight particle characteristics.
Sihao Deng - One of the best experts on this subject based on the ideXlab platform.
-
a spherical surface Coating thickness model for a robotized thermal spray system
Robotics and Computer-integrated Manufacturing, 2019Co-Authors: Yanjun Zhang, Han Lin Liao, Wenbo Li, Chao Zhang, Yicha Zhang, Sihao DengAbstract:Abstract Coating thickness prediction is critical for robotic thermal spray system's tool-path planning. Current prediction models could not give accurate estimation for a type of important spherical Coating surfaces in industrial application. To facilitate tool-path generation and improve the Coating Quality for this special surface shape, this paper proposes a new analytical thickness prediction model. Both numerical simulation and experimental testing are conducted. The results reveal that the model is flexible and efficient to predict the Coating thickness and uniformity in acceptable tolerance and expedient to predict the Coating thickness on non-holonomic spherical surfaces. It could be used for automatic tool-path generation for the robotic thermal spray system.
-
effects of substrate heat accumulation on the cold sprayed ni Coating Quality microstructure evolution and tribological performance
Surface & Coatings Technology, 2019Co-Authors: Sihao Deng, Chaoyue Chen, Yingchun Xie, Xinliang Xie, Xingchen Yan, Renzhong Huang, Jiang Wang, Zhongming Ren, Han Lin LiaoAbstract:Abstract The residual stress and distortion caused by non-uniform temperature distribution has limited the application of cold spray (CS) technique as an effective additive manufacturing and damage repair method for large-scale components. In order to investigate the influence of heat accumulation on Coating Quality, two types of CS Ni Coatings with different building dimensions were deposited onto substrates. The type II Ni Coatings with smaller fabrication size possess a fully dense microstructure without cracks, while the type I Coatings with larger size show a significantly higher porosity value. The type II Coatings show relatively higher microhardness. The tribological tests show that the type II Ni Coatings present a better wear resistance with lower coefficient of friction and lower wear rate. The distinct worn morphologies show that the lower microhardness and porous microstructure of type I Coatings lead to numerous delamination and exposure of interior Coating. According to the temperature history recorded by infrared imaging camera, higher average temperature was found at the type II Coatings due to enhanced heat accumulation of Coating/substrate system at the short nozzle movement. The increased particle plastic deformation can further promote the Coating densification rate and further ameliorate the Coating Quality. It can be summarized that the nozzle trajectory and deposition strategy can affect the temperature distribution and determine the Coating qualities. This work provides a potential guidance for the optimization of Coating Quality by cold spraying additive manufacturing.
-
the effect of spray distance and scanning step on the Coating thickness uniformity in cold spray process
Journal of Thermal Spray Technology, 2014Co-Authors: Zhenhua Cai, Han Lin Liao, Sihao Deng, Chunnian Zeng, Ghislain MontavonAbstract:In the process of cold spray applications, robot kinematic parameters represent significant influences on the Coating Quality. Those parameters include: spray distance, spray angle, gun relative velocity to substrate, scanning step, and cycle numbers. The combined effects which are caused by their interactions determine the Coating thickness. The increasing requirements of Coating productivity lead to the objectivity of analyzing the effect of robot kinematic parameters. So it becomes necessary to optimize the robot trajectory for spraying process in order to obtain a desired Coating thickness. This study aims at investigating the relationship between the Coating profile and the spray distance, scanning step, and introducing the basic principle of a software toolkit named thermal spray toolkit (TST) developed in our laboratory to generate the optimized robot trajectories in spray processes including thermal spray and cold spray. Experiments have been carried out to check the reliability of the simulated Coating profile and the calculated Coating thickness by TST.
-
application of robot offline programming in thermal spraying
Surface & Coatings Technology, 2012Co-Authors: Sihao Deng, Han Lin Liao, Zhenhua Cai, Dandan Fang, Ghislain MontavonAbstract:Abstract Nowadays, robot manipulators have already been widely used in thermal spraying. They can be programmed in two ways: online and offline programming. The first programming method is easy to operate but difficult to guarantee the Quality of Coatings, especially for some complex workpieces. The offline programming technology is a good solution that can overcome the online programming tolerances by using the CAD files of the workpiece. The purpose of this study is to introduce the current applications of offline programming technology in thermal spraying, including some popular methods of path generation, process simulation, robot kinematics optimization, etc. In the last part of this paper, two examples of offline programming in thermal spraying were presented which refer to the trajectory optimization on a workpiece with a great angle and path generation on the complex workpiece with external axis. The simulations and experiments have proved that offline programming can effectively improve the production efficiency and Coating Quality.
-
the effect of robot kinematics on the Coating thickness uniformity
Journal of Thermal Spray Technology, 2010Co-Authors: D Fang, Han Lin Liao, Sihao Deng, Christian CoddetAbstract:The torch speed is one of the most important operating parameters in thermal spraying. Generally, in order to keep a uniform Coating thickness, the movement of the torch should be constant. Nevertheless, when the torch follows a large trajectory angle, the torch speed will decrease significantly, which leads to an irregular Coating thickness. This phenomenon is caused by the weight of different devices fixed on the robot and the combination of the robot’s six axes. It is therefore necessary to optimize robot kinematics behaviors in this case. In this paper, the works concentrate mainly on the relationship between the robot kinematics property and the Coating Quality to find an adequate model for the torch speed optimization. An add-in program based on RobotStudio™ (ABB, Sweden) is developed to determine and optimize the spray trajectory. The optimal trajectory was verified by both the simulations and the experiments.