Research on Process Parameters of High Precision Direct-Ink-Write 3D Printing of Poly(L-lactide-co-ε-caprolactone)报告人:
The process parameters of the high precision direct-ink-write 3D printing of Poly(L-lactide-co-ε-caprolactone)(PLCL) were studied in this report. The excellent biocompatibility and high elasticity make the PLCL an ideal material which can be applied in biocompatible scaffold. Due to the low viscosity of PLCL melt, the PLCL scaffolds is highly appropriate to be manufactured by direct-ink-write 3D printing. The special rheological behavior of the PLCL which is a kind of polymer, leads to the die swell phenomenon during the printing process. That is to say the diameters of printed threads and the nozzle are different, which leads to a gap between the designed size and the true size of printed scaffolds. Adjusting the parameters of printing process based on the experience to decrease the difference between the diameters of printed threads and the nozzle is a common method to increase the precision of printing. However, this method lacks of reliability and repeatability. The purpose of this research is to explore the influence of three important process parameters of the direct-ink-write 3D printing process of PLCL on the diameters of printed threads: extrusion force, temperature and the speed of spraying. We found the optimal process parameters of the high precision printing. The viscosity curves of PLCL with varying shear rates at different temperatures varied from 180℃ to 60℃ and the complex modulus(storage modulus and loss modulus) curves with the temperature decreased from 190℃ to 10℃ were measured through the rotation rheometer, which is shown in figure 1.iii) and figure 1.iv). As shown in figure 1.i), an experimental platform which can control the extrusion force, temperature was set up to find out the relationships between these process parameters and the diameters of threads.(figure 1.ii)) The three parameters were recorded and the diameters of the printed threads was measured. And eventually, the PLCL were printed with high precision and high stability based on the optimized combination of process parameters.