Research On Robot-Based Placement Equipment And Process Simulation Of Thermoplastic Composite

Thermoplastic composite has gradually become the research hotspot of scholars at home and abroad due to their low manufacturing cost and good weldability.Compared with foreign research in this field,research on the placement of thermoplastic composite materials in China is relatively backward.There are less researches on the placement equipment and process of polyetheretherketone materials with superior mechanical properties.The research on the placement process of thermoplastic composites can better guide the research of related theories and the development of the placement equipment,which is of great significance for improving the manufacturing level of China’s aerospace structural components.Firstly,to realize the placement of the thermoplastic composite material CF/PEEK,this thesis optimizes the structure of the existing thermoplastic composite placement head,including cooling,guiding and heating devices,and then simulates the temperature field of the consolidation roller during the placement process.To improve the placement efficiency of the CF/PEEK thermoplastic prepreg,a series of robot placement auxiliary equipment,including positioner and slitter-winder integrated machine,etc.have been designed.The designed laying head can meet the laying requirements of various thermoplastic prepregs such as CF/PEEK,and the slitting-winding integrated machine can divide the wide prepreg tape into prepregs of different widths.Secondly,for the robot placement system,a technical solution that can switch the robot body control system to the Siemens 840 D sl CNC system to control the robot is proposed.The CNC system control cabinet is built and debugged.The CNC system can directly control the robot in the Cartesian coordinate system motion.Aiming at the cylindrical mandrel,a 45° laying track is designed using the fixed angle method,and a post-processing software that can export G codes is compiled.In order to meet the temperature and tow width control requirements of the laying process,a constant temperature heating platform and a slitting-winding machine control system are built respectively.The temperature control accuracy of the heating platform is ±1℃,and the temperature distribution accuracy of each point does not exceed ±3℃.Then,taking CF/PEEK cylindrical shell components as the research object,and improving the buckling performance of CF/PEEK cylindrical shell as the research goal,the mechanical properties of CF/PEEK materials under thin shell parts with different radii of curvature are studied.Using ABAQUS,the cylindrical shell is modelled,meshed,and analyzed for buckling failure under axial load and external pressure load.Explore and analyze the influence of the radius of curvature and the ratio of length to diameter on the mechanical properties of CF/PEEK cylindrical shells under certain ply angle combinations and ply thickness.The results show that when the material thickness is 2mm,the thermoplastic composite CF/PEEK cylindrical shell with geometric dimensions R=600mm and L/R=1 can obtain the best buckling stability.Finally,the Cai Wu tensor criterion is used to verify that the cylindrical shell does not have strength failure when the buckling fails,and the main failure mode of the cylindrical shell is buckling failure.Finally,based on the mechanical analysis results of the cylindrical shell,the process simulation analysis of the thermoplastic composite material surface laying process is carried out.A two-dimensional heat transfer model of the thermoplastic prepreg surface laying process is established by using a laying surface with a radius of curvature of R=600mm.The two-dimensional heat transfer model is established and meshed by writing the APDL command flow in ANSYS,Transient thermal analysis is carried out using the "Life and Death" unit technology.By analyzing the influence of mold temperature,laying speed and heating temperature on the temperature field of the first layer and multiple layers in curved surface laying,it is concluded that in the thermoplastic curved surface laying with curvature radius R=600mm,the recommended combination of process parameters for the first layer laying is mold temperature 145℃,laying speed 5mm/s,heating temperature 750℃;The recommended combination of process parameters for the 10～16 layer laying: mold temperature 145℃,laying speed 25～35mm/s,heating temperature 550℃.