Digital Twins towards Microwave-assisted 3D Printing of Continuous Carbon Fiber Reinforced Composites

Abstract

Microwave-assisted 3D printing based on the fused filament fabrication (FFF) method is an emerging technology to print lightweight continuous carbon fiber reinforced thermoplastics (CCFRP) at high speed. Different from traditional FFF, microwave offers selective and volumetric heating properties to melt thermoplastic materials instantaneously, and the microwave printing head and nozzle remain at room temperature. These advantages can increase the printing speed of CCFRP significantly, while the belt slippage of a printing bed is noticed during microwave-assisted 3D printing. The slippage of the moving belt happens because the cold nozzle moves at high speed and encounters resistance from the rough surface of the printed filament. To solve this problem, this paper presents a hierarchical digital twin (DT) framework, consisting of core and basic DTs, for the prevention of belt slippage induced printing malfunction. The core DTs use MATLAB Simscape multibody models to simulate the printing process virtually and the printing G-code is corrected before printing. In addition, an accelerometer installed on the printing bed is connected to the core DTs. Abnormal vibration signals due to belt slippage can be measured and communicated with core DTs for interrupting and correcting the process. By monitoring the temperature of the heated filament and the output microwave power, the service life of the nozzle and microwave cable are evaluated in the basic DTs.