Modelling 3D melt electrospinning direct write by using response surface methodology

Official URL: http://risc01.sabanciuniv.edu/record=b1649240 (Table of Contents)

Additive manufacturing has been one of the most disruptive manufacturing technology for manufacturing complex geometries. Fused deposition modeling, selective laser sintering/melting, photolithography and multi-jet printing are some major categories of additive manufacturing technologies. Extrusion-based printing or fused deposition modeling is one of the most common additive manufacturing method among other processes because of its simplicity in implementation and hardware. There have been wide variety of application of extrusion based printing from medical to consumer products. Especially, syringe-based printing has been used to fabricate porous structures called scaffolds for tissue engineering. One of the limitation of extrusion based additive manufacturing methods is minimum size of the extruded fiber dimeter. The extruded fiber diameter cannot be decreased beyond the certain nozzle diameter because of the viscosit y of the extruded material. To overcome this limitation, melt electrospinning direct write has recently been developed. In this technique, fiber size can be decreased down to a few microns in diameter. However, the process depends on optimizing multiple process parameters to print straight fibers with controlled diameter. Melt electrospinning direct write method includes many process parameters which might affect fiber diameter and shape of the fiber in terms of being straight or whipping. To investigate the process parameters of the melt electrospinning direct write (MEW), a MEW based additive manufacturing process has been developed. Then one-factor-at-a-time approach has been used for several process parameters such as feed rate, distance, pressure, voltage and temperature. This approach is initially used to understand individual effects of the parameters on fiber diameter. To explain the interaction effects of the parameters, response surface methodology has then been developed. As a result, feed rate, pressure, and temperature have found as significant parameters. However, voltage and distance parameters did not have enough statistical evidence to classify them as significant. By using the selected significant parameters, a fiber diameter of 1.52 microns has been achieved.