Synergizing strength and flexibility: investigating mechanical properties of photopolymer resin blends in DLP 3D printing

The implementation of digital light processing (DLP) 3D printing technology has significantly advanced additive manufacturing (AM), allowing for the production of highly accurate three-dimensional parts with customizable mechanical properties. This study evaluated the mechanical properties of photopolymer resins, specifically in blends of standard and flexible resins, to determine their effect on tensile strength, elongation, hardness, fracture surface and chemical functional group analysis. The test results showed that the standard resin (R) had the highest tensile strength of 15.660 MPa. However, the inclusion of the flexible resin (F) resulted in a gradual decrease in tensile strength, reaching its lowest value of 0.417 MPa when the flexible resin composition reached 100. Furthermore, the hardness tests showed a correlation between the amount of flexible resin and a decrease in hardness. Sample R had the maximum Shore D hardness of 62.9, while sample F had a Shore A hardness of 48.8. Examination of the fracture surface revealed that the addition of more flexible resin to the blend resulted in a rougher fracture surface. Sample F had the highest Ra value of 5.59 μm. The study found that the mechanical strength of the material was dramatically reduced when flexible resin was added to increase the material’s flexibility. However, the material’s ability to tolerate plastic deformation without premature failure was increased. The results play a critical role in identifying the ideal resin composition for specific applications of DLP 3D printing technology, particularly those that require a harmonious combination of strength and flexibility. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.