Simon Crane, Julian Goulding
Victoria University of Wellington
Synthetic Anatomy explores multi-material 3D printing, 3D scanning and its application in the maxillofacial prosthetics industry. The project utilizes MRI and exterior 3D scanning to create anatomically correct ear prosthetics. Research was undertaken on the shore hardness of 3D printed materials and human tissue to design and print an ear that not only looked correct, but behaved like a human ear. Different materials were used to simulate tissues such as skin, cartilage and the ear lobe. The outcome is an ear prosthesis that is anatomically unique, fits the user perfectly and has the tactile qualities of a real ear.2. The Brief: Summarize the problem you set out to solve. What was the context for the project, and what was the challenge posed to you?
The prosthetics industry has not kept up with the rapid advancements in manufacturing and scanning technology to date. The process of design and manufacture in the industry is archaic, the same as it was 10 years ago. Ears are currently made from molds and silicon casting. These ears, although made to look identical to existing ears, have a crude connection to the head and the casting process has to be done every few years as they deteriorate over time. The result is an ear that is not unique, robust or refined. The aim was to turn this archaic design and manufacture into a completely digital process. 3D printing and scanning has the ability to allow greater control, fit and customization ever before.
The question was; could we design an artifact that works with the body and adds unique value to the wearer? Currently, maxillofacial prosthetics are seen as somewhat crude and impersonal replacements for lost facial features. Was it possible to turn a static prosthetic into an object than can move an feel like real body part? We proposed that multi-material 3D printing and 3D scanning could change prosthetics valuable tactile artifacts that users will be proud to wear. The challenge was to create an ear that fits physically, anatomically and visually to become an invisible yet integral part of the body.
We aimed to bring an empathetic view to a very under-designed industry. We wanted to change the way people viewed prosthetics, as not just a corrective addition but as a designed object of quality and desire. Through our research we aimed to translate medical and scientific data into design information that could drive design decisions. This meant true patient information transformed static prosthetics into dynamic objects. Our vision was to create a prosthetic concept that was personal, relevant to the user and had real meaning.
The brief we were given was to re-create anatomy through multi-material 3D printing, coming as close as possible to re-creating the tactile experience of the human ear. We worked within this brief throughout the process but focused heavily on the medical implications of the possible product and to improve the confidence of the wearer.
The focus of this project was to change how people used and designed maxillofacial prosthetics through new manufacturing and design techniques. We researched existing production techniques in maxillofacial prosthetics including ear, eye and dental prosthetic manufacture from expert Craig Metcalfe. We found a completely analog process using unchanged techniques.
Throughout our design process we consulted with a cosmetic surgery practice and maxillofacial surgeon Wayne Gillingham, who specializes in maxillofacial prosthetics. He advised us on current problems with ear prosthetics and the problems his patients have when wearing the current design. He believed the industry needed to embrace 3D printing and scanning to help minimize time and labour.
We researched material densities of different body tissues. Through various scientific papers we discovered a relationship between the shore hardness of particular body parts and digital materials from the Objet Connex 500 multi-material 3D printer.
MRI and CT scans became the basis of creating anatomically correct prosthetics. The Houndsfeild scale defined the relationship between particular body parts and their thresholds in MRI scans. This ensured we were extracting the correct data from the scans. This data could then be moved into 3D modeling programs for further editing and testing of accuracy in 3D printing.
The Xbox Kinect was used to get exterior scans of the body. We conducted scan tests to see whether we could get the accuracy needed to design objects to fit the body. Experiments into various forms were undertaken to fit over the exact curvature of the skin.
We also conducted explorative research in Rhino and Grasshopper to create new structures for the ear. These were designed to remove material while keeping the basic shape and enhancing the tactile experience of the ear. The shapes were based on the ear’s polygon structure and then iterated upon.
The design of the prosthetic ear went through an iterative process that tested a range of different scanning methods, software and digital materials to create the most accurate fitting and looking ear. Creating the correct cartilage took the most experimentation and testing, as this was a complex process to create a perfect fit it inside the skin of the ear. The iterative process involved many software applications, analysis and test prints to make sure the geometry of the ear was clean and printable.
The end result was a refined process to be achieved in 24 hours. This included the initial scan, 3D modeling and design through to final print and clean. This proved that a completely digital process could save a huge amount of time and labour in this industry. Further detailed information on the research and design process can be found in the supporting PDF.
The outcome of this project is a prosthetic that can restore self-confidence with a seamless fit to the body and its surroundings. It increases user confidence knowing their prosthetic was designed from their body, for their body. Using various materials in one print to create a dynamic feeling prosthetic is an area not explored before. It adds value, weight and a tactile experience to the prosthesis that makes it a preferred alternative.
The process undertaken is as equally important as the outcome. It shows a completely digital process is a viable alternative to the existing production techniques. This means the time and labour in designing and manufacturing a maxillofacial prosthesis can be reduced significantly. The switch to additive manufacture means a more sustainable life-cycle and more durable materials than silicon are used. 3D scanning can revolutionise the fitting process by using a scan of the ear location for a perfect prosthetic fit instead of the existing bar and clip technique.
This could accumulate to a large reduction in cost for the patient and a faster path from consultation to receiving a prosthetic. An entire digital process means design changes can be done digitally without making a new mold and replacements can be printed instantly without the need for users to visit a clinic.
The process could also cross markets into the movie and costume industry, where multi-material 3D printing and 3D scanning could be used to design perfectly fitting movie prosthetics with dynamic tactile qualities for unique and life-like costumes.