voxeljet AG expands its portfolio of on-demand 3D printing services

Alongside the standard polymer PA12, TPU is one of the polymers increasingly in demand for 3D polymer printing. With its cushioning properties, the thermoplastic material has proven itself for decades in the production of shoe soles, it offers impact protection and is being used more and more across industries: in the plastics processing industry, in the automotive and consumer goods industry, in aerospace and in the engineering sector.

In the production of polymer components, voxeljet takes advantage of the special material properties of TPU in conjunction with the HSS technology: TPU can be very soft and elastic or very hard and persistent.

These properties can be specifically influenced in all three dimensions using HSS technology. In High Speed Sintering, a fine layer of polymer powder is applied onto a heated build platform and the areas where the part is to be built are then inked with a heat-absorbing ink.

Infrared light is used to fuse the printed areas of the polymer powder, leaving unprinted material loose. Layer by layer, the polymer is applied, printed, and irradiated until the build-up of the full jobbox and the parts within it, is complete. How soft or solid the part is depending on the volume of infrared-absorbing ink introduced. The more heavily a build area is inked, the stronger the part.

By using industrial inkjet print heads, it is possible to print correspondingly different gray levels within a layer and thus realize different product properties per layer. In addition to this grayscale printing, the strength of a component can also be influenced by its geometry. Lattice structures with different wall thicknesses are used to print geometries that can be adapted to individual load profiles in order to save additional material.

“The HSS technology in combination with the TPU material allows us to provide an inherently hard, highly stressable part with soft properties. This opens up completely new and highly individual application possibilities of 3D printing for plastic parts,” says Tobias Grün, Global Product Manager at voxeljet.

TPU components produced with the HSS printing process have particularly long-lasting permanent elasticity and excellent rebound properties compared to other TPU 3D printing processes. The successfully passed Cytotoxicity test also confirms that there is no damage to cells and tissue when the material comes into contact with the skin. In addition, no discoloration of the components occurs.

“With the HSS process, we can produce individualized polymer parts on-demand at high quality and speed at comparatively low cost. High Speed Sintering is an economical, efficient and resource-saving solution due to the use of large-format print heads. The technology offers enormous potential for future-oriented products,” says Tobias Grün.

The TPU qualified for the HSS technology was co-developed by voxeljet and materials manufacturer Covestro.

“The close cooperation between material and machine manufacturers enabled us to bundle our joint know-how and thus coordinate and optimize the part quality as well as the 3D printing process.” says Grün.

With the collaboration, the two companies aim to develop integrated material and process solutions for the economical additive high-volume production of polymer components.

Find out more about voxeljet at voxeljet.com.

For mroe information about Covestro, please visit covestro.com.