Concrete 3D Printing Technology Research With Robot

In the course of human civilization,the ornamental value of architecture has never been ignored,especially in the Chinese civilization that attaches importance to the harmonious coexistence of man and nature.However,the design of special buildings is usually strange,complex structure,and requires customized production,resulting in higher costs.Nowdays,with the wider application of 3D printing technology,it is becoming more and more valuable to apply it to the construction of architecture.This paper systematically analyzes and studies the materials,equipment,and path planning about it.The material of 3D printing architecture is concrete.In this paper,the orthogonal experiment is designed to use multi-index assessment and step-by-step optimization to study concrete materials suitable for 3D printing requirements.The material is mainly composed of aggregate,gel material,external additive,and water.Based on the indicators of condensation time,slump degree,extrusionability,stackability performance,and strength after coagulation,the orthogonal experiment analyzes the materials with different rubber sand ratios,water-to-glue ratios,retarder dosage,and water reducer dosage,and analyzes the influence of different variables on the material properties and size.Finally,the best 3D printing performance was used as the material used in other research directions in the later stage,and the rubber-sand ratio was 0.6,the water-to-glue ratio was 0.4,the retardant dosage was 1.5%,and the water reducer dosage was 0.1%,and the density,viscosity and other parameters of the material were detected.One of the key equipment for concrete 3D printing is the extrusion material mechanism,and its function requirements are continuous,stable and controllable extruded concrete materials.First of all,the spiral extruder is designed according to the main indicators such as concrete aggregate particle diameter,material viscosity,fluidity,equipment productivity,printing speed,etc.,and the fluid dynamic analysis is applied to FLUENT in the later stage to optimize the main structural parameters of the spiral extruder.According to the three simulation results of speed streamline,outlet mass flow rate and total pressure distribution of the flow field.The screw pitch,screw groove and discharge caliber of the spiral extruder are optimized and improved,and the pitch is determined to be 90 mm,the depth of the screw groove is30 mm,and the diameter of the outlet is 40 mm,and the extrusion mechanism suitable for concrete 3D printing is obtained.Different from hot-melt materials such as metals and plastics,concrete materials are difficult to have the characteristics of instantaneous or extremely short-term condensation,and it is essential to focus on the impact of condensation time on the 3D printing process.After the material exceeds the initial coagulation time,it loses its fluidity and plasticity,so when planning the 3D path,it is necessary to optimize the initial coagulation time to ensure that the material is stacked on the path before losing its fluidity.So,this paper comprehensively analyzes the advantages and disadvantages of different filling paths,and selects the filling path method with contour offset,which has the advantages of fewer start and stop times,less empty travel,less bending on the path,and higher material filling rate for concrete materials.Then,using the time window as a restriction,the genetic algorithm is used to optimize the sorting of the starting point of each printed outline,and the traversal of all the contours is completed within the specified time.Based on the above research content,the 3D printing experiment of the concrete module was designed,and the experiment selected the six-axis robotic arm as the moving body,combined with concrete mixer,concrete conveying pump,screw extruder and other equipment,as well as control cabinets,PLCs,drives,frequency converters and other electronic control units to build an experimental platform.According to the requirements of 3D printing engineering experiments,the offline programming software is used to set the motion trajectory of the robot arm according to the planned path,and after obtaining the program,it is imported into the control cabinet,and the spiral extruder at the end of the control arm is moved according to the contour shape,and then the concrete conveyor pump that transports the material is used to achieve 3D printing operations.Through the analysis of the experimental results,it was determined that the motor speed of 30r/min in the spiral extruder was more in line with the process requirements.Finally,it was verified that concrete 3D printing technology is feasible for specific buildings,and the research results provide a certain reference for production process innovation in the construction industry.