A new granule extrusion-based for 3D printing of POE: studying the effect of printing parameters on mechanical properties with "response surface methodology"

Printing elastomers face major challenges due to properties such as high melt strength, high shrinkage rate, and the potential for buckling during printing. This paper introduces the first use of pellet extrusion-based "fused deposition modeling" (FDM) for directly printing polyolefin elastomers (POE). In addition, the impact of critical parameters in this printing process (speed, nozzle temperature, and diameter) was investigated using Box-Behnken design (BBD). The analysis of variance (ANOVA) revealed that most factors had P values below 0.05, indicating their significant influence on the results. The P values for ultimate tensile strength (UTS), elongation, and modulus of elasticity model were 0.0118, 0.0001, and 0.007, respectively. Experimental results demonstrated UTS values ranging from 2.76 to 4.88 MPa and elongation values ranging from 1575 to 2788%. Scanning electron microscopy (SEM) imaging of fracture cross-sections showed acceptable quality of printed samples, although the upper layers of the bed exhibited noticeable shrinkage. Increasing the speed and reducing the nozzle temperature can effectively decrease the cooling rate, enhancing adhesion quality and reducing microholes, as long as it does not negatively impact the feeding rate. These findings, which demonstrate the ability to print high-quality elastomeric parts and overcome printing limitations, have the potential to attract more attention and expand the printing of functional elastomers in various fields.