Customizing Prosthetic Leg Socket by using Rapid Prototype with Reverse Engineering

The demand of using prosthetic leg keeps on increasing due to unpredictable of
certain diseases or physical trauma such as accident and war. Prosthetic devices can
help, but making a prosthetic leg can be a long and difficult process. Standard made
prosthetic leg come ready-made in various standard sizes, though they are often not as
realistic as their custom-made counterparts. Custom-made prosthetic legs are generally
more expensive which costing thousands of US dollars, depending on the level of detail.
This case study describes implementation of rapid prototyping and reverse engineering
technology on customizing the prosthetic leg socket. A negative mold was obtained
from the amputee stump with plaster of paris. The positive mold is generated from
negative mold and taken to the 3D Renishaw Digitizer machine for reverse engineering.
3D Renishaw Digitizer machine will produce 3D point cloud data from the scanning
result. Unigraphics is used to fix, repair and customize the 3D point cloud data into 3D
solid modeling and convert into STL file format before send to the Rapid Prototype
machine to produce the rapid prototype part. Final rapid prototype part is in wax form,
therefore Rapid tooling is needed in order to make the socket of the prosthetic leg more
realistic by using the thermoplastic or engineering plastic material. For this FYP project,
due to the cost budget of a FYP student is limited the real size of the prosthetic leg
socket for this project has been scale down into 80mmX50nunX45mm in order to show
the rapid tooling process. The different between the fmal part of the prosthetic leg of the
rapid tooling with the rapid prototype is plastic material which can sustain high strength
compare with wax. Therefore, a scale down of this project is essential to save material
cost of the rapid tooling process.