Research On Accuracy Control Technology Of Layered Superimposed Printing Concrete Members

For a long time,the construction method of construction projects was limited by the traditional construction tools and technical means,the imagination and creativity of the architects were difficult to achieve,and the rough construction method caused serious damage to the environment.Architectural 3D printing technology is a brand-new automatic construction technology.It is based on 3D printing technology.It is a non-templated construction technology realized by using cement,sand,mineral admixture and reinforcing fiber as raw materials,completely subverting the traditional construction process.mode.The rapid solidification of layered superimposed printed materials to form concrete members is a common process in architectural 3D printing.The molding accuracy of concrete 3D printing components is affected by material properties,printing equipment and printing process.Different printing processes for different printing equipment and printing materials will result in different component forming effects.The application of the optimized printing process can form a concrete member with high molding precision and excellent internal quality.This paper develops a polar coordinate concrete 3D printing device based on the "Key Technology and Demonstration of Industrial Building Parts and Components Manufacturing" project,and conducts theoretical analysis and experimental research on the printing process parameters that affect the forming precision,and establishes process parameters and The relationship model between molding precisions proposes a printing process that uses pre-distortion technology to improve molding accuracy.The main work of this paper is as follows:(1)Layered overlay printing technology for architectural 3D printing process,developed a tower-arm type concrete 3D printing device based on polar coordinate system,changed the traditional XYZ coordinate system control positioning system,and adopted R?Z control positioning system with flexible equipment installation and more suitable for complex curved surface form.,and the design of the numerical control system function,the motion system and the extrusion system of the device is completed,and the printing device is assembled and landed.Since the device is not equipped with a data processing system,the general slice software Cura is used to demonstrate the slice layering,path planning and G code generation of the proposed model,and provide ideas for the development of a data processing system for subsequent printing devices.(2)The error factors affecting the forming precision of the printing member are analyzed,and the main working parameters are separated: layer thickness,lap width,extrusion speed and feed rate.The error test analysis is carried out for the main parameters,and the mathematical modeling method is used to determine the mathematical expression of the step effect error caused by the layer thickness;the maximum likelihood estimation method is used to determine the matching relationship between the extrusion speed and the feed rate;The influence of parameters on the forming accuracy.The lap width and layer thickness of the selected printing process parameters are independent variables,and the influence of printing process parameters on the mechanical properties of the printing components is determined by mechanical properties test.(3)According to the error influence rule of the previous article,a pre-correction printing process is established.The pre-correction printing model is designed.According to the model features and experimental conditions,the direct layering method based on 3D model is adopted to determine the model layering method.The partition contour offset filling method is proposed to determine the model printing path.According to the feed rate and extrusion speed.Matching the relationship,compiling the model G code;using CIMCO Edit8 software for dynamic simulation,evaluating the correctness of the printing process;completing the physical construction process of the design model.(4)Design comparison test,three-dimensional scanning of the Oriental Gate model using pre-correction printing process and non-pre-correction printing process,obtaining point cloud data of printing model,processing point cloud data by Gemagic Studio software,reconstructing 3D model After the deviation analysis with the original design model,the conclusion of the deviation test and the correctness of the process design are proved.