ExoBreast
A moldable and customizable prosthesis for breast cancer survivors
ExoBreast introduces an innovative breast prosthesis that embedded in a one-piece garment, offering key advantages over traditional silicone prostheses, including lightweight and moldability. This is achieved through a hybrid manufacturing approach that combines hand weaving and digital fabrication. We present two fabrication methods using PLA with a desktop 3D printer, the thermal extrusion of yarn and scaffold-based techniques. Additionally, we propose a comprehensive pipeline for custom prosthesis production, incorporating a digital workflow (3D scanning, flattening algorithms) and physical fabrication (3D printing, weaving, and molding). Our design enables users to create breast prostheses with a customized fit tailored to their unique body shapes.
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Team: Rosalie Lin, Olaitan Adisa
Advisor: Lining Yao (Director of Morphing Matter Lab at UC Berkeley)
Reversible and customizable shaping of prosthesis
Our main concept is to enable end-users to easily shape their Exo-Breast at its soft, tunable states by 1) heating it up to 60-70°C with easily accessible home appliances, and 2) remodeling it on their body or a 3D printed customized silhouette. This shape-reversible materiality enables end-users to customize one-piece fabric upon their demands both aesthetically and functionally.
Computational design and fabrication pipeline
An overview of the pipeline is divided into the following stages: (a) body scanning to get the silhouette, (b) generating breast prosthesis on the scanned body, (c) 3D printing the breast area as the physical mold, (d-g) transforming 3D volume to the 2D pattern with flattening algorithm, (h-j) 3D printing the scaffold and weaving it with off-the-shelf yarns, (k-m) heating and molding the ExoBreast on the pre-printed breast mold or mannequin, and (n-o) attaching the ExoBreast to fit garment design. The overall pipeline proposes an end-to-end procedure for a rapid-customizable prototype
Material properties & Fabrication methods
Build on top of the shape-memory property of thermoplastic, we have two fabrication approaches: For a method: We leverage the heat-drawing technique from a desktop 3d printer to deploy the PLA into thin, soft, and lightweight yarns. For b method: We print the PLA as a scaffold, in which it functions not only as material but as a loom, the weaving tool. By weaving off-the-shelf yarns with PLA yarn or scaffold, we are able to produce a piece of shape-reversible fabric without the exposure of thermoplastic.
Woven structure enables varying stretchability
Due to some deviation of transformation from 3D volume to 2D shape or vice versa, we look into stretchability as a parameter to adjust the fabric’s 3D geometry. We zoom into the weaving pattern to see how implementing different angles between the warp and weft axis can result in various levels of stretchability. Woven fabrics are anisotropic materials with different elastic constants based on the direction of applied tensile force when the direction of tensile force is 45 degrees to the direction of the weave, the Poisson's ratio, and the modulus of elasticity is the highest for fabric.
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The same boundary area but different weaving patterns can result in different 3D geometry after being stretched and molded at the triggered soft state. End-users are thus able to hands-on optimize the prosthesis upon their aesthetic (size, curvature) or functional (stiff, soft) preferences.
Tuning stiffness through density of material
The shape-holding capability relates to the stiffness of the fabric. We then leverage different levels of yarn density to enable different levels of softness within one piece. The main idea is to fabricate a prosthesis in one run with both rigid support for the underwire region and softness to the rest of the area.
Interview with Breast Cancer Survivors
This is an iterative design process, in which we had in-depth interviews with three survivors at different phases of application development, as shown in figure 8. Each iteration consists of our prototype demo and survivor’s feedback, with one followed by the other sequentially. We started off by introducing our concept, better understanding their experience with the current prosthesis and their expectations, and asking them to conduct a survey. The interviews are conducted over Zoom, while the prototype is presented by video.
