Microhardness and Abrasive Wear-Induced Material Loss in FDM-Printed PLA, PETG, ABS, ASA, and Fe-Filled PLA

This exploratory study comparatively evaluated the time-dependent abrasive wear-induced material loss, local microhardness, and worn-surface morphology of fused deposition modeling (FDM)-printed PLA, PETG, ABS, ASA, and PLA containing 1 wt.% Fe under controlled wet–abrasive grinding. Two physical cylindrical specimens from the same print build were tested concurrently in opposing holder positions against P180 SiC abrasive paper under continuous water lubrication for 60 min at a normal load of 5 N. After 60 min, cumulative mass losses were 11.1% for PLA, 13.0% for PETG, 22.6% for PLA–1 wt.% Fe, 39.3% for ABS, and 50.1% for ASA. Based on the two specimen-level means, Vickers microhardness (HV0.1) was highest for PLA–1 wt.% Fe (28.5), followed by PLA (22.4) and ABS (13.3), while ASA (11.9) and PETG (11.8) showed very similar values. Optical microscopy and selected SEM/EDS observations revealed material-dependent surface features and showed local Fe detectability in the analyzed regions of the filled PLA. The microhardness ranking did not follow the cumulative material-loss trend, most clearly for Fe-filled PLA and for PETG versus ASA. These results indicate that the local indentation-hardness ranking did not correspond directly to the cumulative mass-loss ranking of the investigated FDM-printed polymers under the selected conditions. For material selection in FDM components subjected to abrasive contact, these findings indicate that local microhardness should not be used alone as a proxy for condition-specific abrasive wear performance.