by Thinking about an artificial link means thinking about a person. It is an object of touch and movement that are manufactured for use that is followed by the body and interacts with the world of the user.
Historical artifacts of prostheses are far from this context lived. Your users are gone. They are damaged – deteriorated by time and exposure to the elements. They are motionless, kept in the museum.
However, such artifacts are rare direct sources in the life of historical amputated. We concentrate on the tools amputed, which are used in Europe of the 16th and 17th centuries. At that time there are only a few records from the perspectives of the amputated, and those who exist say little about how everyday life was with a prosthesis.
Engineering offers historians new instruments to examine physical evidence. This is particularly important for examining the early modern mechanical hands, a new kind of prosthetic technology that occurred around the turn of the 16th century. Most artifacts are of unknown origin. Many only work partially and others do not work at all. Your practical functions remain a mystery.
However, the computer -aided design software can help scientists to reconstruct the internal mechanisms of the artifacts. This in turn helps us understand how the objects have moved.
It is even more exciting that 3D printing that scientists can create physical models. Instead of imagining how a Renaissance prosthesis worked, scientists can test one physically. It is a form of the investigation that opens up new opportunities to research the development of prosthetic technology and user experience over the centuries. It creates a trace of bread crumbs that can bring us closer to the everyday experiences of pre -modern amputes.
But how does it work, which brings two very different fields together, looks in action?
What follows is an insight into our experience in working in a team of historians and engineers who are told by the history of a week. In cooperation, we shared a model of a 16th century prosthesis with the public and learned a lesson about people and technology.
A historian meets a broken model
The historian: On a cloudy day at the end of March, I entered the center of the University of Alabama Birmingham for teaching and learning to keep a weatherproof case and excitement. In the foam inserts of the case, there was a functioning 3D printed model of a 500-year-old hand prosthesis.
It broke fifteen minutes later.
For two years my historian and engineers at Auburn University had tirelessly worked on transforming themselves into an idea of turning mechanisms of an artifact from the 16th century back into reality. The original iron prosthesis, the Kasselhand, is one of around 35 from Renaissance Europe, which is known today.
As a modern historian who studies these artifacts, I work with a mechanical engineer, Chad Rose, to find new ways to explore them. The Kassel hand is our case study. Our goal is to learn more about the life of the unknown person who used this artifact 500 years ago.
With the help of 3D printed models, we carried out experiments to test what types of activities his user could have had with him. We have modeled cost-effective polylactic acid plastic to make this fragile artifact accessible to everyone with a 3D printer of the consumer. However, before we share our files with the public, we had to see how the model was doing when others dealt with it.
An invitation to the guest lecture on our experiments in Birmingham was our opportunity to do exactly that.
We brought two models with us. The main publication lever broke first in one and then the other. This lever has a triangular inner plate connected to a thin bar that protrudes like a trigger from the wrist. After the fingers were pressed into a closed position, it is the only way to free them. When it breaks, your fingers stay tight.
I was amazed. During the test, the model had raised a 20-pound simulation of a chest lid through its fingertips. The first time that we shared it with a general audience, a mechanism that had never broken in the tests just snapped.
Was it a printing error? Material defect? Design error?
We have our hand whisperer: consulted our senior student engineer, whose feeling it appears to work for the model, sometimes supernatural.
An engineer becomes a hand whisperer
The engineer: I was sitting at my desk in Auburn’s mechanical engineering 3D printing laboratory when I heard the news.
As a doctorate for mechanical engineering, which focuses on additive production, which is generally referred to as 3D printing, I research how this technology is used to reconstruct historical mechanisms. In the two years in which I worked on this project, I got to know the Kassel hand model well. When we have a fine-tuned designs, I created and edited its computer-aided design files-the digital 3D constructions of the model and printed and compiled its parts countless times.
The examination of parts with the middle of the context is a decisive control point for our prototypes. This quality control catches, corrects and prevents errors such as incorrectly printed or damaged parts. It is crucial to create consistent and repeatable experiments. The laboratory never leaves a new model version or a new change in component, without standing without strict inspection. This process means that this model has behaved over time that the rest of the team has never seen before. But I have.
When I heard that the publication lever in Birmingham was broken, it was just a Thursday. While it had never snapped when we tested the model for humans, I had seen how it broke many times while we carried out checks on components.
After all, the model consists of relatively weak polylactic acid. Perhaps the most difficult part of our work is to make a plastic model as durable as possible and to visually see it with the 500-year-old. The iron rod of the lever of the artifact can do more power than our plastic version with at least five times the earnings strength.
I suspected that the lever had caught because people had withdrawn the deduction too far back and too quickly. So the challenge was to prevent this. But the redesign of the lever or another form would make it less like the historical artifact.
This threw the question: Why could I use the model without breaking the lever, but nobody else?
The team makes a plan
The team: A flood of the discussion led to a growing consensus – the core of the problem was not the model, but the user.
The carrier of the original Kassel hand would have learned to use their prosthesis through practice. Our team had also learned to use the model over time. Due to the process of design and development, prototype and printing, we accidentally practiced how it is used.
We had to teach others to do the same. And this demanded a two -track approach.
The engineers have examined the opening again, through which the release triggers were pushed out of the model. They suggested to shorten it to limit how far the back users could draw it. When we checked how this change would affect the accuracy of the model, we found that a smaller opening actually came closer to the dimensions of the artifact. While the larger opening was required for an earlier version of the release lever, which had to continue traveling, it now only caused problems. The engineers got to work.
In the meantime, the historians created plans to document and share the various techniques for the operation of the model that the team had not recognized that it had annoyed it. To teach someone at home how to do your own copy, we have made a short video in which explains how to spend your fingers and release your fingers, and troubleshooting when a finger connects.
Test the plan
Exactly a week after what we called “The Birmingham Break”, we once again shared the model with a general audience. This time we visited the history lessons of a colleague in Auburn.
We brought four copies with us. Everyone had an assignment to shorten the opening around the deduction. First we played our new teaching video on a projector. Then we handed over the models to the students to try it.
The result? Not a single broken lever. We have publicly introduced the project on the schedule.
The process of introducing the Kassel handmodel into public highlights that, like the 16th century amput, you had to learn to use it to use the 3D printed model.
It is a strong memory that technology is not just a question of mechanisms and design. Basically, it’s about people – and how people use it.
This article will be released from the conversation, a non -profit, independent news organization that brings you facts and trustworthy analyzes to help you understand our complex world. It was written by: Heidi Hausse, Auburn University and Peden Jones, Auburn University
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Heidi Hausse received funds from Duke August Library; the consortium for the history of science, technology and medicine; The American Council of Scholarized Societies; The Huntington Library; The Society of Fellows in the humanities of Columbia University; And the Renaissance Society of America.
Peden Jones received funds from the Renaissance Society of America.
