Lattice-shaped and TPU printed shoe sole with HSS technology (photo credits: Voxeljet)
Manufacturer renowned for its large format 3D printers, Voxeljet has decided to extend its on-demand 3D printing service to flexible TPU parts. Almost a year ago, the German company teamed up with the chemist Covestro (acquired this summer by Stratasys), to formulate a thermoplastic polyurethane compatible with its high-speed HSS technology.
Based on a material jet process, remember that this involves spreading a thin layer of polymer powder on a hot plate. An inkjet head then deposits droplets of resin on the areas to be printed. The layers of powder are thus superimposed while being progressively sintered using infrared light. According to the company, this process makes it possible to manufacture functional prototypes such as supports or housings, but also all kinds of end-use parts.
A few years ago the technology had been adapted to print TPU, with particularly interesting results since it made it possible to achieve minimum wall thicknesses of only 0.15 mm.
TPU is one of those technical materials which, due to its nature, which is not easily compatible with additive manufacturing, appeared late on the market. From the family of thermoplastic elastomers, this polyurethane has properties of flexibility, damping and high wear resistance that open the door to many applications. TPU parts are often used in industry for waterproofing and packaging, shoes, for the padding of helmets, saddles or seats, or elastic tubes and hoses.
“This opens up completely new and very individual application possibilities of 3D printing for plastic parts”
Bicycle saddle printed using HSS technology (photo credits: Voxeljet)
” The HSS technology in combination with the TPU material allows us to provide an inherently hard and highly stress resistant part with elastic properties. This opens up entirely new and very individual application possibilities of 3D printing for plastic parts,” comments Tobias Grün, Global Product Manager, voxeljet AG. ” With the HSS process, we can produce custom polymer parts on demand with high quality and speed at a relatively low cost. High-speed sintering is an economical, efficient and resource-saving solution through the use of large format printheads. Technology offers enormous potential for the products of the future. »
In addition to the speed of its HSS technology, Voxeljet has another advantage called ” grayscale 3D printing “. A process that adds an extra degree of customization, since it allows parts to be created with different material properties. In this way the user can influence for example the mechanical resistance, the elasticity or the density. VoxeJet adds that these properties can be changed individually in different areas of the part, without it being visible in the component.
VoxelJet’s decision to extend its service to TPU appears all the more relevant as the German manufacturer’s equipment is particularly expensive and bulky. The opening of a TPU service also seems to want to address this segment of customers who do not have sufficient order volume to justify such an investment. The learning time needed to master such technology is the other argument in favor of this strategy.
In their desire to allow companies and their customers to access personalized polymer components, Covestro and voxeljet have no intention of stopping their collaboration with TPU. Other material developments being considered are thermoplastic elastomers (TPE), polybutylene terephthalate (PBT) and polypropylene (PP).
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