Influence of the melt electrowriting process parameters on poly (ε-caprolactone) (PCL) scaffold thickness

This study investigated the effects of varying temperature, voltage, air pressure, collection speed, collection height, and nozzle inner diameter on scaffold thickness using poly (ε-caprolactone)(PCL) through single-factor experiments. A fiber layer packing index (F_p) was defined to quantify the tightness of the fiber arrangement or interlayer bonding. Experimental results revealed that: elevated temperature increased fiber diameter and intensified interlayer fusion, leading to significant scaffold height reduction; Higher voltage refined the fibers but caused disordered deposition and a sharp reduction in layer number at excessive levels; Increased air pressure thickened the fibers and induced interlayer fusion; Faster collection speed refined the fibers while reducing thickness; Greater collection height significantly increased layer number but reduced interlayer adhesion when excessively high; Smaller nozzle inner diameter refined the fibers but caused a disordered fiber arrangement below critical dimensions. The maximum scaffold thickness reached 3.43 mm with 235 layers. Additionally, three failure modes were observed: disordered fiber deposition, polymer droplet formation, and interlayer fusion.