At the Institute of Biomedical Engineering, a variety of innovative rapid prototyping processes are available to realize high-quality concept models, prototypes or functional parts within few hours. The part is first created using a CAD program or reverse engineered using 3D scanners and then produced using one of the following processes.
PolyJet process (PJ):
In the PJ process, a UV resin (liquid model material) is applied in layers by a print head to build up the part. The layer heights are less than 16 µm, so that a very high surface quality is realized. Model materials available include polypropylene simulating, flexible, transparent or biocompatible (prEN ISO 10993-1:2017) UV resins.
Fused Deposition Modeling (FDM):
Fused Deposition Modelling (FDM):
In this additive process, a plastic filament is melted and applied layer by layer through a nozzle. Parts can be made from ABS or PLA, for example. Radiation-resistant, bone-simulating, intrinsically electrically conductive or FDA-approved materials can also be 3D printed.
Selective Laser Sintering (SLS):
The SLS process uses a powder of elastic polyurethane or very rigid polyamide. A laser selectively melts the powder. When a layer has been created, a roller smooths the powder and the process begins again. A special feature of this 3D printing process is that no additional supports need to be added to the object. The powder acts as a support material, so enormous overhangs and undercuts can be achieved without removing supports.
UV-LCD Stereolithography (SL):
In UV-LCD stereolithography, a UV resin is located in a tank above a UV-LCD. The model to be 3D printed is now broken down into layers and these appear as a projection on the UV-LCD. By moving the printing plate layer by layer and exposing it to the corresponding projections, the UV resin is cured piece by piece until the finished part has been created.
Vacuum casting is mostly used to create parts from castable polyurethanes, epoxies or ceramics. First, a master pattern of the part is prepared and moulded with polyadditive silicones. After removal of the master pattern, the cavity is filled with the casting material. The vacuum is required for bubble-free, homogeneous potting. The creation of multiple cavities for the production of several hundred parts with one casting are also possible. Due to the variety of casting materials, different properties of the parts can be realized: different Shore hardness, transparent, refractory, thermally conductive, dielectrically modified, etc.