Ultrafast 3D printer for high-performance plastics

Seeking to speed up the additive manufacture of large-volume plastic components, researchers at the Fraunhofer Institute for Machine Tools and Forming Technology IWU have developed Screw Extrusion Additive Manufacturing (SEAM) — a system and process that is eight times faster than conventional 3D printing.

3D printers that build small souvenirs layer by layer from melted plastic are often used at tradeshows, where it can take up to an hour to produce a pocket-sized souvenir. This process is far too slow for the mass-production of components, as required by the automotive industry, for instance.

In comparison, the system developed at Fraunhofer IWU takes only 18 min to produce a plastic component that is 30 cm high, making it suitable for the additive manufacture of large-volume resilient plastic components. The printer achieves these ultrafast speeds “by combining machine tool technology with 3D printing”, explained Fraunhofer IWU’s Dr Martin Kausch.

To process the plastic, the researchers use a specially designed unit that melts the raw material and ejects it at a high output rate. This unit is installed above a construction platform that can be swivelled in six axes by using the motion system of a machine tool — a unique set-up, according to Dr Kausch.

The hot plastic is deposited in layers on the construction platform. The motion system of the machine ensures that the construction panel slides along under the nozzle in such a way that the previously programmed component shape is produced. The table can be moved at a speed of one metre per second in the X-, Y- and Z-axes and can also be tilted by up to 45°.

“This enables us to print eight times faster than conventional processes, enormously reducing the production times for plastic components,” said Dr Kausch.

This experimental component is a hybrid of CFRP sheet metal and 3D printed structures — SEAM makes it possible to print on injection-moulded components or sheet metal for the first time. Image ©Fraunhofer IWU

Every hour, up to 7 kg of plastic are pressed through the hot nozzle with a diameter of 1 mm; comparable 3D printing processes, such as fused deposition modelling (FDM) or fused filament modelling (FLM), usually achieve only 50 g of plastic per hour. Instead of expensive FLM filament, SEAM processes free-flowing, cost-effective standard plastic granulate into resilient, fibre-reinforced components that are several metres in size, allowing material costs to be reduced by a factor of 200. Researchers can also implement complex geometries without supporting structures and even print on existing injection-moulded components.

“As our construction platform can be swivelled, we are able to print on curved structures with a separately moving Z-axis,” Dr Kausch noted. “In tests, we were able to process a wide variety of plastics. They ranged from thermoplastic elastomers to high-performance plastics with a 50% content of carbon fibre. These plastics are materials that are particularly relevant to industry and cannot be processed with traditional 3D printers.”

Tool manufacturers as well as the automotive and aerospace industries are expected to benefit from the innovative 3D printer.

Top image caption: SEAM can accelerate the additive manufacture of plastic components eightfold over conventional processes. Image ©Fraunhofer IWU

Please follow us and share on Twitter and Facebook. You can also subscribe for FREE to our weekly newsletter and bimonthly magazine.