| PAM(pressure assisted micro-syringe) free forming technology is a new kind of rapid prototyping technology, which has a distinct advantage in the fabrication of scaffolds of composite bio-materials. This paper aims to research pneumatic printing technology to explore the extrusion forming regularity of system by designing effective printing loop; and then to study the effect of pressure, length-diameter ratio and the viscosity of material on molding in the process of extrusion, the author adopted software simulation. Besides, practical experiment was utilized to further analyze the influence of those factors and implement the verification and supplementation with simulation conclusions to explore proper process of PAM, which would be applied to practical fabrication. Finally, relevant control program was developed to explore the preliminary design of system control.The design of pneumatic system determines the stability and efficiency of it. By comparing the two designs the thesis obtained the proper one and at the same time the effect of negative pressure was verified. Meanwhile, the influence of flow values on the system outputs in the process of extrusion has been discussed.Pressure P, viscosity of material ? and length-diameter ratio affect the property of materials in the extrusion process. The thesis revealed the effects of those factors on material in the printing process by using software to simulate the extrusion process and the effects of those factors were discussed after simulation.Material diameters is one of the important performance parameters after extrusion, which directly impacts the biological performances of the scaffolds. The effect of viscosity of material and external pressure on forming performance was explored via the control of them in the printing process,. The results were verified with the simulation results to get proper process parameters of material forming. |
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