Development of low-shrinkage eco-friendly composite materials for the DLP 3D printing technique

Abstract

3D printing technology has emerged as a production method in the past ten years and has attracted great attention in the market. Among various printing systems, digital light processing (DLP) 3D printing has extremely high planar resolution with a smooth sample surface, which is the best advantage of this technology. However, this 3D printing technology currently has three major challenges that urgently need to be improved: (1) the sample has dimensional shrinkage defects after secondary light curing; (2) the mechanical properties of the printed product have a serious tendency to decrease after secondary curing; and (3) the choice of printing materials used lacks diversification. The aforementioned defects will seriously affect the yield of printed products in high-precision manufacturing. In this research, eco-friendly carbon black has been added to the photosensitive resin of DLP to form composites. The mechanical properties of the material, thermogravimetric analysis, material viscosity, surface morphology and size shrinkage were investigated. In the tensile test, the area after the yield point is also significantly prolonged, which indicates better toughness of the composite resins. Adding recycled carbon black to the material can also enhance the heat resistance and thermal stability of the resin without increasing the solution viscosity. The newly synthesized composite resin demonstrated an improved hardness without severe size shrinkage after the post UV curing process, and also provided a new solution to the issue of abandoned tires.