Research On 3D Printing Related Methods Based On 6-axis Robotic Arm

The joint space of robotic arm has the advantages of high flexibility,large working range and high precision,which can carry out complex operations and is widely used in welding,spraying,automatic wire laying,automotive manufacturing and other industrial occasions.The application of robotic arm to 3D printing technology makes up for the defects of traditional Cartesian and Delta-type 3D printers with small working space,poor printing accuracy and inability to repair or reprint existing objects.The layering algorithm,the filling path planning algorithm,and the kinematics of the robotic arm are the key factors that affect the modeling quality and printing efficiency in the 3D printing process.Therefore,this paper investigates the layering algorithm,filling path planning algorithm,and robotic arm kinematics in robotic arm3 D printing,and builds a robotic arm 3D printing simulation platform.The main research works are as follows:(1)For the problem of inefficiency of the traditional equal layer thickness slicing algorithm,an equal layer thickness topological layering algorithm based on layer height matching is proposed.Due to the cumulative stacking process of 3D printing in the Z-axis molding direction layer by layer,if the layered thickness setting is not reasonable,it will produce the step effect and lead to the degradation of the model molding quality.In order to reduce the influence of the step effect on the model and prevent the loss and offset of model feature details,an adaptive layering algorithm is proposed to retain the feature details of STL model.The experimental results show that the algorithm reduces the step effect and the loss and offset of model features,and improves the printing accuracy of the model.(2)To address the problems of poor printing accuracy,low printing efficiency and failure to guarantee the mechanical properties of the model by existing 3D filling path planning algorithms,a combined filling path algorithm based on contour bias and Hilbert curve is proposed.Combining the advantages of both paths,the contour bias path is used at the edge of the printing area with high accuracy requirements,because the contour bias path can restore the contour shape very well and thus ensure the printing accuracy;the Hilbert curve path is used inside the printing area with low accuracy requirements,because the Hilbert curve does not have high accuracy at the edge and will have a jagged shape when restoring the contour,but the Hilbert curve can be a continuous curve to fill the two-dimensional plane,to avoid the print nozzle empty drive,improve the efficiency of the model printing.In the actual printing process,the filling density of the Hilbert curve can also be set according to the mechanical properties of the model to meet the requirements of the model.(3)The inverse kinematics of the robot arm is proposed based on the positional separation method to address the problem that it is difficult to find the equations of independent uncorrelated variables by the purely analytical method of robot arm inverse kinematics.Firstly,the mathematical model of the abb1200 robotic arm is established using the standard D-H parameter method,and secondly,the positive kinematic equations of the robotic arm are derived based on the space motion theory,and the workspace of the robotic arm is solved using Monte Carlo.Since the arm obeys Pieper’s criterion,its inverse kinematics can be decoupled,i.e.,the first three joint angles are solved by geometric method,and the last three joint angles are solved by analytical method to find their corresponding nonlinear equations,which simplifies the complex nonlinear equation system that is difficult to solve by purely analytical method.In order to solve the inverse kinematics of the robotic arm by the geometric method and the analytical method,which are limited by the configuration and are not universal for different configurations of the robotic arm,an inverse kinematic method based on the adaptive improved differential evolution algorithm is proposed.The experimental results show that the method still has good convergence accuracy and convergence speed compared with the basic differential evolution algorithm without falling into local optimum.(4)A robotic arm 3D printing simulation experimental platform is built to realize the functions of displaying STL models,layering processing,exporting Gcode commands,and simulating the robotic arm 3D printing process to further verify the feasibility of the scheme in this paper.