Micro Droplet Generated by Dual-Differential Piezoelectric Ejection for Powder-Based 3D Printer

The surgery time can be reduced by allografting from bone-substitute material or donors while compared to the autograft from patient's own bone. The bone-substitute reconstructed by powder-based 3D printer has high compatibility with human tissue, so it is gradually applied to bone reconstruction in clinical research. In order to construct the proper bone-substitute from the porosity surface of powder and to keep good strength, the profile of ejection droplet is significantly. In the study, we proposed the dual-differential piezoelectric (DDP) technology to obtain the best micro droplet, and discussed the relationship between the operating parameters, droplet dimension and printing gap. In the experiment, the DDP putter was employed to generate the micro droplet, and the high speed camera was used to acquire the droplet images for analysis of droplet dimension. The results show the better operating voltage ranged from 4 to 5 V, and the smallest droplet dimension can be obtained while the triggered frequency of DDP putters decreased; especially from 200 to 100 Hz without phase shift. Besides, the printing gap is about 1 mm in printing process. In future, the results can improve the development of power-based 3D printing system, and the reconstruction bone with advantage of high strength can be printed and actually adopted into the patient's body as the substitute tissue in clinical application.