The element itself is a miniaturized version of the set’s main steam engine, featuring spinning wheels and a chimney that functions. Injection molding has been the LEGO manufacturing backbone since the late 1940s, but this geometry was simply not achieveable with traditional tooling. Designers Bo Park Kristensen and Jae Won Lee worked closely to exploit the freedom granted by additive manufacturing in producing intricate connectors and internal features molding could not deliver. “October 2025 marks a milestone that has never been done before,” Kristensen said. “We have for many years used 3D prints in our development phase, but it is the first time we use it on a full scale.”

The milestone capped a nine-year development program to develop a high-throughput polymer additive manufacturing platform able to reach consumer-level production volumes. Head of Additive Design and Manufacturing Ronen Hadar framed the accomplishment as LEGO’s equivalent of adopting injection moulding in the 1940s. The team’s aspiration wasn’t to replace moulding but to add to the design toolset – to make 3D printed parts “boringly normal” in future sets.

The production system makes use of EOS polymer powder bed fusion technology in the form of an EOS P 500 platform with Fine Detail Resolution. FDR uses an ultra-fine CO₂ laser that enables highly detailed features in nylon-based materials. The LEGO Group chose the process for its combination of dimensional accuracy, mechanical strength, and surface quality-all vital for parts to mesh properly with billions of bricks already in existence. Already, the company has doubled the speed of output from its machines and is looking for even more efficiency gains. Material selection is central to LEGO’s strict safety and durability standards.