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3D printing the cultural history of humanity? Absolutely.

3D production methods are breaking new ground all the time. The unwritten motto of 3D experts seems to be the desire to continually test the limits of the technology. 3D printing is even opening up totally new possibilities for documenting and copying artifacts in the field of archaeology. The latest example is a replica of the figure of a bronze horse rider from an early Celtic chieftain's grave near Unlingen, Germany in the Biberach region of Baden-Württemberg. Using one of its Mlab cusings, Concept Laser has produced a faithful copy of this prehistoric rider. An object nearly 2,800 years old is being printed out of powder.

3D metal printing is making it possible to utilise archaeological discoveries in new ways. By creating a faithful replica, original objects can be evaluated scientifically and replicas made available for exhibitions at the same time. Cultural history is taking shape in 3D printers. Holding the Rider of Unlingen in your hand lets you look back at 28 centuries of cultural history.

The scientific implications of the "Rider of Unlingen"

The Rider of Unlingen is a burial object found in a Celtic chieftain's grave from the Hallstatt culture. This bronze statuette of a rider on a double horse was located in a wagon grave in Unlingen, Germany which had already been robbed in ancient times. The broken edges of the incomplete legs of the horse indicate that the statuette was originally mounted to another object which is no longer preserved. This could have been the top of a bronze lid, the base of a larger bronze vessel or furniture, a wagon or a yoke. The other burial objects date the figurine to the 8th or 7th Century B.C.E. Figurative depictions from this time period are extremely rare in southern Germany. The Rider of Unlingen represents one of the oldest depictions of a horse rider north of the Alps. This figurine is a unique early Celtic piece in Central Europe.

The "Rider of Unlingen" 3D project

The transition from molding to additive manufacturing opens up new prospects for scientific evaluation in the field of archaeology, as well as the exhibition of objects in several different places at the same time. Until just a few years ago, discoveries could only be reproduced through direct molding, a process which always risks damaging the original. Through the use of additive 3D technology, it is now possible to produce copies without contacting the original at all. To digitise the "Rider of Unlingen" object from the Hallstatt culture, a specialised process known as x-ray computer tomography (CT) was used. The bronze horse rider was x-rayed three dimensionally and evaluated using the "VG Studio Max 3.0" software from Volume Graphics. The STL data obtained through this process makes it possible to transfer the industrial 3D printing process of today over to applications in the field of archaeology. In the meantime, the technical progress being made in terms of material variety and printing precision is enormous. For the 3D printing job, Concept Laser provided the Baden-Württemberg State Office for the Preservation of Monuments with its LaserCUSING technology in the form of an Mlab cusing. Concept Laser's material engineers also found a bronze alloy similar to the original: a modern copper-tin alloy with a density and specific weight approximating those of the artifact from the 8th/7th Century B.C.E. The precise percentages of copper and tin could still be determined using x-ray fluorescence analysis. This is how the "Rider of Unlingen" was printed in bronze true to the original. Visually and tactfully, the reproduction horse rider is on par with the original piece.

Outlook

The additive manufacturing of faithful replicas through 3D printing is opening up new prospects for the field of archaeology, making discovered metal objects available for scientific purposes. At the same time, copies can be exhibited to museum visitors. Essentially, multiple copies of historical discoveries can be printed out and used, where only experts would be able to tell the difference through material analysis, as the production process uses powder of modern origin. Even the issue of re-engineering isn't taboo – theoretically, it should even be possible to reconstruct heavily damaged objects in the future. These objects would then have the same shape as the original production, enabling the destructive traces of history on them to be erased. Artifacts from humanity's past give us a glimpse of our cultural history, and 3D printing makes it possible to experience this history in a tangible way.

Summary

The implications of additive 3D printing for archaeological artifacts and discoveries:

  • Archaeological discoveries with delicate and complex structures can be reproduced highly accurately
  • The 3D printing process enables the contact-less reproduction of artifacts without damaging them
  • Replicas are absolutely accurate in every detail and faithful to the original
  • Replicas can be made accessible to museums while the originals remain in archives for research purposes
  • High density, comparable feel and high surface quality
  • Considerably shortened development time and expense for mold-less replicas of unique objects
  • No tools to buy, less waste
  • Possibility of re-engineering in the case of broken objects.

Interview with head conservator Nicole Ebinger-Rist of the Baden-Württemberg State Office for the Preservation of Monuments on the regional board of Stuttgart, Germany

Fascinating history from the world of 3D printing may not be that unusual, but the history of a horse rider discovery from the Hallstatt culture is especially interesting. In a brief interview, Nicole Ebinger-Rist explained just what motivates a conservator to get involved with 3D printing.

Editor: What implications does 3D printing have for the future of exhibitions in practice?

Nicole Ebinger-Rist: The replica created is being shown as part of the exhibition entitled "The Rider of Unlingen" – Celts, horses and charioteers. It's a exhibition at two museums showing what state-of-the-art technology can do today. True-to-detail reproduction without direct molding (which could potentially damage discovered objects) is crucial here. In the museum world, original specimens are grouped together in exhibitions, allowing them to be contrasted with comparable objects. These comparative collections give exhibition visitors and scientific researchers insight in a historical context. A replica which is faithful to the original can be made accessible at museums in many different places around the world. Theoretically, it should even be possible to reconstruct heavily damaged objects in the future, which would give the object its original shape back. Essentially, we'd be able to erase the destructive traces of history from an object.

Editor: What form does cooperation between partners of the 3D project take?

Nicole Ebinger-Rist: Volume Graphics in Heidelberg, Germany suggested the idea of using 3D metal printing to produce replicas. In a CT scanner, we were able to capture the shape of the "Rider of Unlingen" as STL data without touching or damaging it. We printed out the horse rider using the LaserCUSING process on a machine from Concept Laser. Concept Laser also lent us their material expertise. The historical rider is made of a copper alloy from the Iron Age, and we did not want to remove any material for a precise analysis. The 3D metal printing experts found a copper alloy for us which comes very close to the original in terms of specific weight and density distribution. It was an exciting journey for all of us.

Editor: How convincing is the appearance of a replica like this?

Nicole Ebinger-Rist: I was very surprised by the level of detail. All of a sudden, you're holding an object from the 7th Century B.C.E. in your hands, except that it's made out of powder from the 21st Century. You've got a cultural-historically relevant copy in your hands and are looking at 28 centuries gone by. It's simply overwhelming. 3D printing is a wild technology. Every archaeological find has it's own magic, especially when they are as unique as the "Rider of Unlingen." When you're holding a reproduction which resembles the original one-to-one, it's a very special thing, and very important for further research. Whole new possibilities are being opened up to curators, conservators and scientists.

Editor: Thank you very much for the interview today.