Researchers fromtu Wien及其聚合物制造立方已经开发了一种SLA 3D可打印的象牙替代品，可用于恢复受损的历史文物。
Once printed, the scientists’ ‘Digory’ material, composed of a synthetic resin embedded with calcium phosphate and silicon oxide, yields parts with a similar appearance and properties to real ivory. Utilizing the new polymer, the team have been able to repair a 17th century coffin, proving its potential as a less wasteful, time-consuming and more elephant-friendly way of renovating monuments.
“With our specially-developed 3D printing systems, we process different material formulations for completely different areas of application, but this project was also something new for us,” said Konstanze Seidler of Cubicure’s Material R&D division. “In any case, it’s further proof of how diverse the possible applications of SLA are.”
Identifying an ivory substitute
Often sourced from elephant tusks or the teeth of warthogs, walruses or hippopotamuses, ivory is highly sought after because it combines rigid durability with attractive aesthetics. However, due to the ethical concerns raised by poaching, international trading of the material has been banned since 1989, and this has left many damaged ivory artefacts without a means of repair.
尽管各种替代品是由聚合物，酪蛋白甚至象牙木屑制成的，但它们通常是批量生产的，这意味着需要在资源繁重的过程中划出零件。同时，3D印刷越来越多地用于恢复文化古迹，因此艾迪生修复reached out to Cubicure last year on behalf of the Archdiocese of Vienna, for help repairing a historical casket.
“The research project began with a valuable 17th century state casket in the parish church of Mauerbach,” said Professor Jürgen Stampfl, from the Institute of Materials Science and Technology at TU Wien. “It is decorated with small ivory ornaments, some of which have been lost over time. The question was whether they could be replaced with 3D printing technology.”
3D打印一列资本
为了准确地复制棺材的外观，科学家通过用磷酸三氯（TCP）颗粒加载二甲基丙烯酸酯树脂制定了新材料，从而产生半透明的浆液。然后，将混合物用彩色颜料上盖上，这是需要完善的精细过程的一部分，以产生精确复制真实人工制品的色调的部分。
“You have to bear in mind that ivory is translucent,” explained Thaddäa Rath, a student who contributed to the project for her dissertation. “Only if you use the right amount of calcium phosphate, will the material have the same translucent properties as ivory.”
一旦准备就绪树脂，研究人员就会使用Cuticure的Caligma 200热光刻3D打印机, creating two sample chess pawns, as well as a column capital for the 17th century tomb. After some manual sandpaper polishing, the scientists compared their samples to genuine ivory, finding that they had a comparable level of density and no crucial inhomogeneities.
The 3D printed replicas also exhibited a similar flexural modulus to ivory, including a flexural strength of 74% under bending. However, the team did concede that the color pigments hadn’t penetrated their replica very well, leading to some height and temperature differences compared to the original, and leaving the process needing some further tweaks before it can be scaled effectively.
In terms of dimensional accuracy and appearance though, the team were able to match the original casket’s columns exactly, even coloring them with black ink to replicate the cracks seen in the damaged articles. As a result, the scientists consider their approach to represent a “big step forward” in artefact restoration, making it much more economically-viable than existing manual techniques.
Preserving history with 3D printing
Utilizing a combination of 3D scanning and printing technologies, it’s now possible to recreate historic monuments with an exceptionally-high level of accuracy. Researchers from theYungang洞穴研究所例如，3D printed ancient Buddhist statue replicas为了公开展示，以保护它们免受潜在的风化。
A team based at London’s帝国战争博物馆(IWM) have taken a similar approach, by using imagery to3D print a 3000 year-old statuereplica. The original monument, called the ‘Lion of Mosul,’ was destroyed by ISIS six years ago, but AM has allowed the researchers to recreate, preserve and display the cultural treasure at a public exhibition.
Similarly, theDubai Future Foundationhas worked as part of a UN-backed initiative for the last four years to3D打印稀有人工制品that have been destroyed by ISIS across Iraq and Syria. Some of the foundation’s work has since been displayed in the “The Spirit in the Stone” exhibition at the UN’s headquarters in New York.
The researchers’ findings are detailed in their paper titled “Developing an ivory-like material for stereolithography-based additive manufacturing.” The research was co-authored by Thaddäa Rath, Otmar Martl, Bernhard Steyrer, Konstanze Seidler, Richard Addison, Elena Holzhausen and Jürgen Stampfl.
To stay up to date with the latest 3D printing news, don’t forget to subscribe to the3D打印行业newsletteror follow us onTwitter或喜欢我们的页面Facebook.
Are you looking for a job in the additive manufacturing industry? Visit3D Printing Jobsfor a selection of roles in the industry.
Featured image shows the researchers’ 3D printed column capital replica alongside the genuine article. Photo via the Applied Materials Today journal.
