The article presents a comprehensive study of the Selective Laser Sintering (SLS) process aimed at improving the accuracy of product manufacturing. A structural and probabilistic model of the resulting shape formation error has been developed, considering various factors affecting manufacturing accuracy: triangulation errors, shrinkage compensation, laser beam settings, and discreteness due to powder material. The study was conducted on additive machines using statistical modeling. The main sources of errors were identified at the stages of triangulation, technological preparation, and layer-by-layer shaping. It was established that the shrinkage compensation error, especially along the Z-axis, is the most significant. The modeling results allowed for determining the achievable shape formation accuracy on the given machine. The developed model enables the prediction of the resulting error and the assessment of risks when creating products with high precision requirements, which is of substantial importance for the effective planning of additive manufacturing processes.