Parameters design and the operation simulation of a pneumatic dispensing system for biomaterial 3D printing
Date
2016
Authors
Zhou, Wenqi
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Abstract
Tissue engineering (TE) combines methods of cells, engineering and materials to improve or replace biological functions of native tissues or organs. Fabricating scaffolds is a vital process in TE for the mechanical support of the cells proliferation with desired functions and intricate structures. A pneumatic dispensing system of 3D printing is used to build soft scaffolds with controllable pore sizes in this research. An effective method is required to help users to systematically select proper parameters to print hydrogel strands with desired widths to fabricate scaffolds. In this research, printing parameters are classified first to build a simplified mathematical model to identify the significant parameters. A factorial experiment is then conducted to investigate effects of selected parameters and their interactions on the strand width. The solution is further verified using single variable experiments with the regression test. Based on the results, a parameters selection method is proposed and evaluated using two verification tests. A comparison test of the scaffolds fabrication is conducted to verify the analytic solution of the proposed theory. It is found that the nozzle sizes, dispensing pressure, and moving speed of a printer head all statistically affect strand widths. Among them, the nozzle size has the most significant influence on strand widths. Factors interactions are mainly embodied in between the nozzle size - moving speed and the nozzle size - dispensing pressure. In addition, a statistical significant linear relationship is found between the moving speed - strand width and the dispensing pressure - strand width. Furthermore, due to the high cost of bio-materials and the high pressure threat of air compressor in the dispensing system, a 3D bio-printing simulation system is developed to demonstrate the system configuration and operation procedures to help new users avoiding operation mistakes in the real world. A haptic-based 3D bio-printing simulation system with the haptic feedback is presented by means of the Phantom Omni haptic interface. The virtual environment is developed using the Worldviz software. The haptic force feedback is calculated based on the spring-damper model and the proxy method. This system is verified using questionnaire survey to provide a flexible, cost-effective, safe, and highly interactive learning environment.
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Keywords
Parameter design, 3D bio-material printing