Development And Experimental Tests Of 3D Printing Bone Tissue Engineering Scaffolds Forming Equipment

There are many cases of bone defects caused by accidents and diseases every year.Bone tissue engineering which is a novel method of bone repair has achieved many valuable research results in bone repairs after nearly three decades of development.Tissue engineering scaffold is one of the three major elements in tissue engineering.And it has always been a research hotspot in academic circles in recent years.Solvent-based Extrusion Freeforming(SEF)is a low-cost extrusion-based 3D printing technology that can control the size and distribution of the filaments or pores of the prepared scaffolds which are excellent in macro/microstructure and pore connectivity.In this paper,through the study of this technology,the extrusion pressure in the extrusion process was numerically simulated.A prototype of the forming equipment was developed at the same time.Then,the forming tests of the bone tissue engineering scaffold were carried out.The contents and results are as follows:(1)Based on the Benbow-Bridgwater model,L9(32)orthogonal tests were designed,which set the extrusion speed and the viscosity of the paste as fixed factors and the extrusion pressure of the paste as the response value.The numerical simulation of pressure values during the extrusion process was simulated by Fluent.Then,the maximum numerical simulation pressure was obtained.(2)According to the modular design ideas,three-dimensional drawing software SolidWorks was used to design the structure of bone tissue engineering scaffolds forming equipment based on Solvent-based Extrusion Freeforming.The static and dynamic behavior of the designed mechanism was analyzed by the finite element analysis software ANSYS Workbench.The results of analysis showed that the designed forming equipment is reasonable and reliable.(3)According to the characteristics of bone tissue engineering scaffolds forming equipment based on Solvent-based Extrusion Freeforming,the design of control system was divided into two parts:a)the hardware environment was mainly composed of Arduino Mega2560 development board and NI USB6009 data acquisition card and its peripherals,which were used for four-axis motion control and data acquisition of extrusion pressure;b)the software system was composed of SolidWorks,Arduino,Lab VIEW and Simplify 3D,which completed three-dimensional modeling,program programming,extrusion pressure acquisition,model slicing and human-machine control of bone tissue engineering scaffolds,respectively.(4)After testing the trajectory control capability of the developed forming equipment in the test phase,the preparation of the paste,the test of extrusion deposition forming,and real-time monitoring of the pressure in the extrusion process were performed.The results of test showed that the relative error between the average extrusion pressure in the "stabilization phase" of the paste extrusion and the numerical simulation of the extrusion pressure was 10.7%.The developed forming equipment can perform extrusion deposition forming of bone tissue engineering scaffolds.