Development Of A Multi-nozzle System Based On MAM And PAM For Multi-material Dispensing

Recently,the additive manufacturing(also known as 3D printing)has become one of the most focused research topics,especially in mechanical engineering(like printing of metals)and medical science(e.g.cell printing).Bone tissue engineering is commonly regarded as the most potential route for the repair of bone defects,in which scaffold is the key.Therefore,more and more researchers are trying various ways to make scaffolds with good biocompatibility,and the vast majority of them are definitely through 3D printing or its combination with other technologies.However,with the development of bone tissue engineering,the requirement of bio-imitability also becomes increasingly demanded,which is difficult for traditional preparation methods and even 3D printing technology to satisfy such needs.So it is far from stopping to explore new methods and techniques for more biomimetic scaffolds,for instance,in materials and structure,for bone tissue engineering.In order to fabricate porous scaffolds with better biological properties,the author studied the optimization of fabrication process of scaffolds from the aspects of structure and composition,based on build a multi-nozzle printing platform with MAM and PAM.Then,the multi-nozzle system is developed to printing “hard and soft” materials(component bionic)for bone tissue engineering,which lay a solid foundation for the realization of high bionic scaffolds.First of all,the mainstream print nozzle system was analyzed.According to the requirement of the bone tissue engineering to the printing process,the multi-nozzle printing system was built by using the MAM and PAM,and the construction scheme of the multi-nozzle printing platform was analyzed in detailSecondly,the MAM was analyzed carefully,its mechanical structure,power supply and control program were designed,the extrusion speed control program was analyzed in detail.According to the actual needs,the temperature control and other modules were added to facilitate the printing of the nozzle.The extrusion printing test proved the reliability of its system.Thirdly,the PAM was thoroughly studied.The pneumatic circuit system was optimized designed and the key devices and components were chosen.Then,the design of the circuit is optimized.According to the actual demand,the amplifier circuit is designed to ensure the optimal circuit system.The pressure curve of the material in the cylinder during printing is determined,therefore the response time of the air pressure and the minimum droplet printing time is determined.Next the satellite droplet and casting problem are solved by the hydrophobic treatment of the nozzle,and the accuracy and stability of the system were analyzed and tested.Finally,in order to realize the operation of the multi-nozzle printing system,the motion control system and the operation interface were designed.The implementation of the hardware control program and the human-computer interaction interface is analyzed.The hardware control program and interface program is written completely.The method of path planning for multi-material model is realized,and the control of the MAM and PAM is achieved.The coordinated printing of the multi-nozzle is implemented,and the coordination of the multi-nozzle system is analyzed.Three sets of multi-nozzle 3D printing system have been developed,including the myself lab,a university in Hubei and a university in Jiangxi.