The bearing points of the deflection lever are particularly smooth-running, durable and wear-resistant. A combination of a glass or carbon fibre-reinforced construction material such as PET-CF and a tribologically optimized material such as an Iglidur Tribo-Filament is ideal here. © Igus

Krause pulls another example of the new flexibility off the shelf: a bearing block for a shaft, printed a few days ago. The main body is made of fiber-reinforced filament. This ensures stability. For the bearing surface, on which the shaft runs at high speeds, the 3D printer uses a particularly wear-resistant tribofilament. "Our customers are delighted with these new printing options. Since the market launch of the expanded 3D printing service at Hannover Messe 2020, orders have been piling up." At present, 2K 3D printing still accounts for a small proportion of capacity. Depending on the complexity, up to several hundred 2K components are produced each week. Selective laser sintering (SLS) remains the big brother. In this process, 3D printers fuse wafer-thin layers of plastic powder to create the finished component. Up to 120,000 parts per week are produced on three SLS systems in Cologne. "Two-component printing is not yet possible with the SLS process. It is reserved for 3D printers that work with the FDM process."

No geometric restrictions

The FDM printers produce components from two plastics in just a few hours - usually faster than is possible with conventional subtractive processes. However, in order to guarantee this smooth process, designers must take the material properties into account in their CAD models. In most cases, the two plastics fuse at the interfaces as if they were two layers of the same material. The more similar the filaments are in terms of polymer compositions and processing temperatures, the better this fusion works. "As the 3D printer can switch between the materials at any time during 2K printing, there are no geometric limitations," explains Krause. "The plastics can surround each other, interlock with each other and alternate in layers." If the melting temperatures are too different and no fusion can take place, then designers should create so-called form-fit connections in the CAD software. In this case, at least two connection partners interlock. One example of such a mechanical fusion is the dovetail with its characteristic wedge shape, in which one narrow side widens to form a wide edge.

Tom Krause, Head of Additive Manufacturing at Igus: "As the 3D printer can switch between materials at any time during 2K printing, there are no geometric limitations." © Igus

The ability to print with multiple materials is another milestone in 3D printing technology, which is establishing itself as a serious manufacturing process in more and more industries, including as an alternative to ablative processes such as turning or milling. A study by the IT industry association Bitkom shows that 32% of industrial companies were already using 3D printing in 2019. For example, to produce prototypes, spare parts, tools and small batches. In 2018 it was 28%, in 2016 only 20%. Many companies have now recognized the potential of 3D printing technology. Not only does it make production more flexible, it also saves costs and conserves resources. However, the technology is not a sure-fire success. Tom Krause: "Our 3D printing service is designed to offer individuals and companies the opportunity to benefit from additive manufacturing with little effort. From a technology that is gaining ground in manufacturing."