High-precision inkjet 3D printing of curved multi-material structures: Morphology evolution and optimization

Multi-material printing is a significant developmental trend in the field of rapid prototyping. However, research on the simulation and prediction of multi-material formation is still at the droplet level and unable to calculate the changes in multi-material interface morphologies caused by flow and solidification. Additionally, it is not possible to predict the overall morphologies of the multi-material interfaces in a sample. Therefore, this paper proposes a multi-material morphology evolution prediction model based on convolution gradient calculations. Using semi-empirical model of multi-material droplet sliding and spreading, overlapping flow, and the multimaterial droplet film solidification model, precise predictions of deposition, flow, and solidification between multiple materials were achieved and extended to curved surface deposition. Based on the prediction results, we designed an iterative optimization method for the droplet distribution and droplet grayscale to realize highprecision jet deposition, solidification, and sintering integrated forming technology for multi-material samples. This method has an interface inclination prediction error of less than 0.8 degrees and height error of less than 10 mu m, with the interface inclination approaching 0 degrees after iterative optimization. This method can be used for the high-precision printing of devices such as antennas and metamaterials. Based on microstrip antenna printing results, the center frequency was 14.9 GHz, return loss at the center frequency was 34.22 dB, and return loss was 10 dB in the 13.6-15.4 GHz band, providing a foundation for the conformal manufacturing of high-performance multi-material electronic devices.