Laser Cladding Path Planning Study For PDC Drill Bits

PDC bits,as a major oilfield drilling equipment,are subject to localized damage to the substrate area due to harsh working conditions and various factors at the bottom of the well.This paper is based on the reverse engineering technology of PDC.In this paper,the point cloud data of the PDC drill was collected based on the reverse engineering technology,and the fusion model of the defective area of the PDC drill was obtained.The path planning tool was developed based on NX,and the interface between the PDC drill laser melting path planning and the actual robot repair was realized.The specific research methods are as follows:Data acquisition of PDC drill bits.A 3D laser scanner was used to collect the point cloud information on the surface of the PDC drill bit,to repair the defects in the scanned face piece model,and to obtain a laser cladding model of the defective area by Boolean differencing the standard PDC drill bit model with the repaired PDC drill bit model.Numerical analysis of the temperature and stress fields during the cladding process in parallel,interlaced and composite cladding paths based on the defective area of the PDC bit.The defect is repaired by layered cladding.The temperature field simulation results show that the heat accumulation effect and temperature gradient of the composite path are the smallest,while the parallel path is the largest and the staggered cladding method can effectively improve the temperature gradient and heat accumulation of the parallel path.The stress field simulation results show that the maximum instantaneous stress in each layer of the composite path and the residual stress along the X and Y directions are better than the other two paths.The deformation simulation results show that the deformation at the sharp corners and corners of the composite path is the smallest and uniform,and the deformation along the Z direction is significantly smaller than the other two paths,and the deformation along the X and Y directions is between the other two paths.Finally,the composite path was chosen as the laser coating path for the defective part of the PDC drill by combining the melting efficiency and the laser lifetime.A laser cladding path planning tool based on the defective part of the PDC drill was developed in UG using NX/Open secondary development tool and Visual studio.Based on NX/Open Menu Script module and NX/Open UIStyle module,we designed the main menu and dialog box interface for specifying the workpiece coordinate system,creating busbars,curve optimization,and internal curve generation tools.The functions of the path planning tool were programmed using NX/Open API functions and C++ functions.The path planning tool was used to compile the exported laser cladding path points into Gcode files.Finally,the path planning tool was used to plan the paths of an arbitrary model of the intercepted PDC drill base part to verify the feasibility of the path planning tool.