PHOTO: Covestro is driving forward the development of high-performance polymers for 3D printing, including TPU, raw materials for PU, coatings and adhesives and polycarbonates
ADDITIVE manufacturing methods such as 3D printing are well on the way to fundamentally changing production processes. They cut mould costs, reduce development times and offer manufacturers considerable design freedom. Significant advances have already been made in rapid prototyping – the computer-aided, cost-effective production of models and prototypes.
However, challenges exist, such as high production costs and the limited availability of materials.
While the consulting firm Roland Berger forecasts a fall in process costs of up to 60% over the next five years, Covestro, formerly Bayer MaterialScience, is driving forward the development of high-performance polymers for existing 3D printing processes. These include thermoplastic polyurethanes (TPU), raw materials for polyurethane (PU) coatings and adhesives, and polycarbonates.
In fused filament fabrication (FFF), a plastic filament is liquefied or heated to deposit lines and dots on to a surface, which then harden when cooled. By repeating this process numerous times, a three-dimensional solid object is created layer by layer.
Covestro sees a wide range of applications for TPU, in particular, as a large proportion of the current Desmopan® portfolio is suitable for the FFF method. The melting and hardening behaviour of TPU results in a permanent bonding between layers, while the outstanding abrasion resistance and elasticity of TPU are maintained.
Polycarbonate is also ideal for this method. Covestro’s is working in partnership with Chinese filament manufacturer Polymaker, which has recently launched polycarbonate-based materials for the FFF method onto the market.
Selective laser sintering is also used to create 3D structures layer by layer in rapid prototyping. This involves using a laser beam to sinter a plastic powder. Covestro developed the TPU material Desmosint for this purpose a few years ago. The product is processed by partner Lehmann&Voss&Co into a powder suitable for laser sintering and marketed under the trade name Luvosint.
In binder jetting, a thin layer of powder consisting of plastic, ceramic or metal particles is spread across the surface. A liquid binding agent is then applied to the layer of powder from an inkjet print head at particular points, where it forms a bond. The next layer is applied and bonded to this, resulting ultimately in a three-dimensional structure that can subsequently be infiltrated for further hardening. Covestro offers various polyurethane products for the powder, infiltrate and binding agent for this method.
Covestro polyurethanes are also ideal for the rapid multijet fusion method. This involves using inkjet printing technology to apply a heat-absorbent ink onto a powder bed, which is then cured using an infrared lamp.
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