Balling behavior of phenolic resin during selective laser sintering process

The balling phenomenon commonly manifests in the selective laser sintering (SLS) 3D printing of phenolic resin materials, significantly impacting molding outcomes and performance. The study determined the optimal preheating temperature of phenolic resin using differential scanning calorimetry (DSC). The correlation between the occurrence of the balling phenomenon and process parameters was investigated through single fusion channel and single-layer sintering tests. Findings indicated that a preheating temperature below the glass transition temperature could induce the balling phenomenon regardless of the process parameter. The optimal preheating temperature was identified as 65 °C, reducing the likelihood of slating and facilitating easier processing of phenolic resin. Two distinct balling phenomena were observed in the single fusion channel experiments, correlating with the depth of the sintering melt pool. In the single-layer sintering tests, the balling phenomenon resulted in the formation of reticulation and large balls. Specifically, achieving well-formed sintered layers was more feasible with a scanning spacing of 0.25 mm. The study offers crucial recommendations for parameter adjustments and temperature control to optimize the SLS 3D printing of phenolic resin materials, aiming to enhance molding outcomes and overall performance.