The Centre for Rapid Prototyping and Manufacturing (CRPM) at Central University of Technology, Free State (CUT) specialises in Additive Manufacturing (AM), better known as 3D printing. The CRPM was established 1997 as a centre for commercial work as well as research using Rapid Prototyping, Rapid Manufacturing, Rapid Tooling and Medical Product Development technologies. In Medical Implant Development, Computer Tomography (CT) scan data is used as input, to develop 3D CAD data for AM processes. The CT data is imported into Mimics, a generalpurpose segmentation program for grey value images, which performs segmentation by thresholding to identify bony structures or soft tissue (on schematic (No 1). The 3D reconstructed data of the anatomy is exported as a STL file to
Magics software, where implants for reconstructive surgery can be designed to fit onto the virtual model of the skeletal area involved (No 2). The implant data is then exported as a slice file to the AM machine, where the implant is fabricated in a layerby- layer process according to each consecutive virtual slice. Medical implants can be produced directly in bio-compatible titanium on the CRPM’s EOSINT (M280) Direct Metal Laser Sintering machine (No 3). Post processing like polishing and cleaning of the DMLS produced implant can be performed (No 4). Final fitment (No 5) of the implant can be done on a preoperative model before the operation, to identitfy fixation. The
DMLS produced prosthesis is implanted during surgery (No 6). Models of any part of the skeleton can be produced from CT data in nylon on the CRPM’s EDS INT P380 or in translucent resin on a 3D-Systems Viper stereo lithography machine. Surgeons can use these models for inspection, planning and risk assessment as well as for test-fitting of surgical jigs, fixtures and implants before the operation is performed. 3D Design software together with the flexibility of the AM processes allow for the fabrication of custom-made medical equipment and devices that would be difficult or impossible through conventional machining techniques. The Product Development Technology Station (PDTS) at CUT together with the CRPM have already developed a number of successful medical devices, some of which are currently being patented and commercialised.