Fico Daniela, Rizzo Daniela, Montagna Francesco, Esposito Corcione Carola
Department of Engineering for Innovation, University of Salento, Edificio P, Campus Ecotekne, s.p. 6 Lecce-Monteroni, 73100 Lecce, Italy.
Department of Cultural Heritage, University of Salento, Via D. Birago 64, 73100 Lecce, Italy.
Materials (Basel). 2023 Apr 12;16(8):3038. doi: 10.3390/ma16083038.
This paper reports a comparison between the advantages and disadvantages of fused filament fabrication (FFF) and computer numerical control (CNC) milling, when applied to a specific case of conservation of cultural heritage: the reproduction of four missing columns of a 17th-century tabernacle. To make the replica prototypes, European pine wood (the original material) was used for CNC milling, while polyethylene terephthalate glycol (PETG) was used for FFF printing. Neat materials were chemically and structurally characterized (FTIR, XRD, DSC, contact angle measurement, colorimetry, and bending tests) before and after artificial aging, in order to study their durability. The comparison showed that although both materials are subject to a decrease in crystallinity (an increase in amorphous bands in XRD diffractograms) and mechanical performance with aging, these characteristics are less evident in PETG (E = 1.13 ± 0.01 GPa and σ = 60.20 ± 2.11 MPa after aging), which retains water repellent (ca = 95.96 ± 5.56°) and colorimetric (∆E = 2.6) properties. Furthermore, the increase in flexural strain (%) in pine wood, from 3.71 ± 0.03% to 4.11 ± 0.02%, makes it not suitable for purpose. Both techniques were then used to produce the same column, showing that for this specific application CNC milling is quicker than FFF, but, at the same time, it is also much more expensive and produces a huge amount of waste material compared to FFF printing. Based on these results, it was assessed that FFF is more suitable for the replication of the specific column. For this reason, only the 3D-printed PETG column was used for the subsequent conservative restoration.
本文报告了在文化遗产保护的一个特定案例中，即复制一座17世纪帐幕的四根缺失柱子时，熔融沉积成型（FFF）和计算机数控（CNC）铣削的优缺点比较。为制作复制品原型，欧洲松木（原始材料）用于CNC铣削，而聚对苯二甲酸乙二醇酯二醇（PETG）用于FFF打印。在人工老化前后，对纯净材料进行了化学和结构表征（傅里叶变换红外光谱、X射线衍射、差示扫描量热法、接触角测量、比色法和弯曲试验），以研究其耐久性。比较表明，尽管两种材料都会随着老化而结晶度降低（XRD衍射图中非晶带增加）和机械性能下降，但这些特性在PETG中不太明显（老化后E = 1.13±0.01 GPa，σ = 60.20±2.11 MPa），PETG保留了疏水（ca = 95.96±5.56°）和比色（∆E = 2.6）性能。此外，松木的弯曲应变（%）从3.71±0.03%增加到4.11±0.02%，使其不适合该用途。然后使用这两种技术制作同一根柱子，结果表明，对于这个特定应用，CNC铣削比FFF更快，但同时，与FFF打印相比，它也更昂贵，并且会产生大量废料。基于这些结果，评估得出FFF更适合复制特定的柱子。因此，后续的保守修复仅使用3D打印的PETG柱子。
