3D Printing of Objects with Continuous Spatial Paths by a Multi-Axis Robotic FFF Platform

Yuan Yao,Yichi Zhang,Maximilian Lackner,Mohamed Aburaia

doi:10.3390/app11114825

Yuan Yao, Yichi Zhang + Show 2 more

Open Access

https://doi.org/10.3390/app11114825

Copy DOI

Abstract

Conventional Fused Filament Fabrication (FFF) equipment can only deposit materials in a single direction, limiting the strength of printed products. Robotic 3D printing provides more degrees of freedom (DOF) to control the material deposition and has become a trend in additive manufacturing. However, there is little discussion on the strength effect of multi-DOF printing. This paper presents an efficient process framework for multi-axis 3D printing based on the robot to improve the strength. A multi-DOF continuous toolpath planning method is designed to promote the printed part’s strength and surface quality. We generate curve layers along the model surfaces and fill Fermat spiral in the layers. The method makes it possible to take full advantage of the multi-axis robot arm to achieve smooth printing on surfaces with high curvature and avoid the staircase effect and collision in the process. To further improve print quality, a control strategy is provided to synchronize the material extrusion and robot arm movement. Experiments show that the tensile strength increases by 22–167% compared with the conventional flat slicing method for curved-surface parts. The surface quality is improved by eliminating the staircase effect. The continuous toolpath planning also supports continuous fiber-reinforced printing without a cutting device. Finally, we compared with other multi-DOF printing, the application scenarios, and limitations are given.

Highlights

IntroductionThe nozzle of the equipment travels along the X/Y/Z axis and deposits the material in the spatial Cartesian coordinate system
Multi-degrees of freedom (DOF) printing gets rid of the limitation of traditional Fused Filament Fabrication (FFF) that deposits materials along a single direction
Unlike conventional FFF printing, we propose a multi-axis continuous toolpath planning method and a process control strategy for the robotic armbased 3D printing platform, making it possible to take full advantage of the multi-axis printing platform’s advantages and improve the mechanical strength and surface quality of the printed part

Summary

Introduction

The nozzle of the equipment travels along the X/Y/Z axis and deposits the material in the spatial Cartesian coordinate system Based on this platform feature, most 3D printing toolpath planning methods can be divided into specific steps: (1) obtain a digital model of the printed part, (2) slice the model equidistant using a set of parallel planes, and (3) perform toolpath planning and generate print toolpaths in each layer section. The sloping surface of printed parts will suffer from the staircase effect because of layering, which affects the surface quality and leads to stress concentration These problems weaken the strength of the FDM product and limit its application scenarios, and prompted the researchers to conduct extensive exploratory work

Methods

Findings

Discussion

Conclusion