Fraunhofer looks to closed-loop 3D-printing with recycled materials

The Fraunhofer Research Institution for Additive Manufacturing Technologies (Fraunhofer IAPT) wants to make recycling in additive manufacturing (AM) economically viable. It has launched a project to boost the use of recycled materials as a resource for the industrial 3D printing of high-quality components.

Recycled polymers offer cost savings and more sustainable production but secondary materials vary from batch to batch. This poses two issues in AM. One is that most 3D printers have fixed parameters and the actual conditions during the printing process are not considered.

This is particularly challenging when recycled materials are used. The other is that individual wear and tear on machines leads to inconsistent results.

‘Failure to account for the variance in recycled materials as well as differences from machine to machine increases scrap rates,’ the institute says.

Closed-loop systems

In the new project on sustainability and profitability in industrial 3D printing, Fraunhofer IAPT experts are combining expertise in virtualisation, digital twins and industrial AI. ‘The goal is a paradigm shift from an open-loop process, which does not account for the printing process, to a closed-loop system,’ a press release states.

In the closed loop, data regarding material quality or wear-related deviations in machine behaviour is fed into the printing process in real time. Fraunhofer IAPT is equipping 3D printers with sensors and computer vision.

The systems monitor the print in real time and record, for example, layer height, extrusion width, vibration and extrusion behaviour. AI algorithms analyse the data during production and adjust the parameters.

Learning systems

Another project goal is to develop 3D printers into learning systems. Digital twins of machines or machine parts can identify optimal combinations. An intelligent data management system links the process data, geometry information and quality metrics collected in the digital twin.

Looking to long-term profitability and seamless scaling, the Fraunhofer IAPT team is designing control strategies and a data framework specifically for use in large printer farms.

A central platform aggregates data from all systems so that insights from one 3D printer regarding a specific recycled material can be transferred to other machines.

Matthias Brück, head of the virtualisation department at Fraunhofer IAPT, says: ‘Recycling in additive manufacturing today fails not because of material availability but because of process uncertainty. With adaptive, data-driven control, we are transforming previous uncertainties into manageable variables. Sustainable 3D printing becomes predictable, certifiable, and economically viable.’