Surface finishing on IN625 additively manufactured surfaces by combined ultrasonic cavitation and abrasion
The poor and non-uniform surface quality of parts produced by powder bed fusion (PBF) processes remains a huge limitation in additive manufacturing. Here we show that ultrasonic cavitation abrasive finishing (UCAF) could improve the surface integrity of PBF surfaces built at various orientations –0°...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
2021
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/154206 |
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| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | The poor and non-uniform surface quality of parts produced by powder bed fusion (PBF) processes remains a huge limitation in additive manufacturing. Here we show that ultrasonic cavitation abrasive finishing (UCAF) could improve the surface integrity of PBF surfaces built at various orientations –0°, 45° and 90°. Average surface roughness, Ra, was reduced from as high as 6.5 μm on side surfaces (90°) to 3.8 μm. Surface morphological observations showed extensive removals of surface irregularities and peak reduction on sloping (45°) and side surfaces. The micro-hardness of the first 100 μm of the surface layer was enhanced up to 15 % post-UCAF. Dimensional changes were minimal and uniquely dependent on the initial surface characteristics. A parametric study further showed the effect of abrasive size, abrasive concentration, ultrasonic amplitude and working gap on UCAF's performance. A moderate abrasive size at 12.5 μm and concentration level at 5 wt% resulted in the lowest final Ra; as the two dominant material removal mechanisms – direct cavitation erosion and micro-abrasive impacts – were balanced. Finally, UCAF was demonstrated to result in 20 % Ra improvement of internal surfaces of a 3 mm diameter channel. |
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