Shrinkage compensation of additively manufactured parts with measured dimensions using affine transformations

Dimensional inaccuracies caused by anisotropic and non-uniform shrinkage remain a critical challenge in additive manufacturing. Existing compensation methods often require extensive calibration, full 3D scanning, or iterative trial-and-error adjustments, limiting their practicality. This paper introduces a streamlined print-measure-edit-reprint framework that corrects shrinkage-induced errors using a combination of global and local affine transformations. Instead of relying on extensive scanning, our method requires only a few critical dimensional measurements to guide the compensation process. The designed 3D model is converted into a triangular mesh, where each vertex receives an optimized affine transformation, ensuring the final print achieves the desired dimensional accuracy. A constrained optimization problem is formulated to enforce smoothness, rigidity, and physical constraints, which is efficiently solved using the Levenberg-Marquardt algorithm. Experimental validation on a 3D-printed bracket demonstrates that the proposed method reduces dimensional error by 74%, significantly improving accuracy without extensive post-processing. This approach provides a generalizable, computationally efficient, and practical solution for shrinkage compensation in a wide range of additive manufacturing processes.