# The Influence of PBF-LB/M Part Forming Angle and Support Structure Parameters on the Distortion of Oral Stent

## TL;DR

This study examines how forming angles and support structures affect distortion in metal 3D-printed oral stents, finding that specific angles and support parameters minimize deformation.

## Contribution

The paper introduces a novel analysis of forming angles and support structure parameters in PBF-LB/M for minimizing oral stent distortion.

## Key findings

- Minimum distortion of 0.667 mm occurs at a forming angle of 75°, while maximum distortion reaches 1.706 mm at 30°.
- Larger support mesh size and spacing directly increase maximum distortion in printed oral stents.
- Support structures reduce distortion by enhancing structural stiffness and facilitating force transmission.

## Abstract

Powder Bed Fusion-Laser Beam/Metals (PBF-LB/M) enables the layer-by-layer fabrication of complex parts; however, non-uniform thermal transients during the process induce high stresses. Geometric constraints dominate stress–relaxation behavior, which is the primary mechanism leading to part distortion. Therefore, the printing structure serves as a major factor influencing the distortion of PBF-LB/M-fabricated components, of which the forming angle and support structure parameters are the two key factors affecting the printing structure. This study investigates the effects of forming angles and support parameters on the distortion behavior of oral stents manufactured via PBF-LB/M. The results indicate that the magnitude of distortion varies significantly with the forming angle, with the minimum distortion of 0.667 mm occurring at 75°, while the maximum distortion reaches 1.706 mm at 30°. Combined stiffness theory and thermal stress analysis reveal that the thermal stress peaks at a forming angle of 30°, which is governed mainly by the printed cross-sectional area per layer and the cumulative build height. Meanwhile, structural stiffness gradually decreases as the forming angle increases. The study also confirms that support parameters significantly affect distortion, confirming that larger support mesh size and spacing directly contribute to increased maximum distortion. Based on stiffness theory and thermal stress analysis, it is concluded that support structures reduce distortion primarily through two mechanisms: enhancing the overall structural stiffness and facilitating force transmission.