Biomaterials for 3D Printing Technologies

Fused Filament Fabrication (FFF) 3D printing technology meets the requirements of individual parts, while being extremely material-saving and capable of processing the high-performance polymer PEEK. Using FFF, the material is melted in filament form, a kind of plastic strand, through the printhead using high temperatures of up to 500 °C and applied in different layers to the desired component. Decisive for the component quality is the controlled solidification process of the semi-crystalline plastic.

Some methods melt or soften the material to produce material layers. Besides the deposition of single elements in the 3D structure, fast and continuous deposition of 1-dimensional structures within the 2D slayer is possible in this technology. In fused filament fabrication, also known as fused deposition modeling (FDM™), the model or part is produced by extruding small beads or streams of material that harden immediately wile cooling to form layered structures. A stream or filament of thermoplastic, a metal filament, or other (composite) material is fed into an extrusion nozzle head (3D printer extruder), which liquefies the material and turns the flow on and off. Meanwhile printers with simultaneous multi material deposition are available, also allowing support structures for complex geometries.

Evonik had already delivered the first polymer powder material for the additive manufacturing market - SLS technology - in 1996, thus setting standards that currently apply to 3D printing of plastic materials.

The principle of additive manufacturing using selective laser sintering
Selective laser sintering is based on the principle of the layer-wise build-up of a structure by combining powders to form a part. In general, the process can be characterized as follows:

• specification of a three-dimensional model in the form of CAD data
• no use of molding tools
• generative build-up; molding occurs not by removal of material, but by applying itany desired geometry
• offers freedom of design

Evonik has many years of experience in developing and processing products that lend themselves specifically to new 3d printing processes. Based on CAD data sets, 3d printing generates complex components through the layerwise application of polymer powders, filaments, fluids, binders or other suitable materials.

The principle is always the same: A material is laid down layer by layer. In practice, however, a wide variety of processes lead to the same result. One of the most important processes is selective laser sintering (SLS). Here, a powder is melted by means of a laser, layer by layer. This produces very precisely detailed and robust components made of either plastic or metal.