The Fraunhofer ILT and MacLean-Fogg have jointly produced a complex die casting tool inlay using Laser Powder Bed Fusion (PBF-LB/M). The specially developed L-40 tool steel enables the additive manufacturing of heavily loaded, large-volume tools for the first time and thus the implementation of conformal cooling. Initial results from smaller tools, which Toyota is already using in series production, indicate a significantly longer service life for the additively manufactured tools. In the current project, a hybrid, large-volume tool was created for the transmission housing of the Toyota Yaris Hybrid. The combined process with conventional preforms plus additively manufactured structures shortens the production time, reduces costs and allows a high number of variants on a combined tool platform.
Additively manufactured die cast tool inlay made from tool steel L-40: The large volumetric mould was produced at Fraunhofer ILT using laser powder bed fusion with conformal cooling. ©Fraunhofer ILT
The automotive industry is in the midst of a profound upheaval. Cost pressure and the transition to electromobility are forcing many manufacturers to fundamentally rethink their vehicle architecture and production processes. Many manufacturers are currently reducing the number of individual pressed parts and striving for as few but highly complex structural components as possible. Particularly in the case of large aluminium components, such as frame or transmission components, this also increases the demands on the tools: They must be thermally highly resilient, allow variants and be able to be adapted to new geometries as quickly as possible.
This change brings with it new challenges: The required casting moulds not only have to be larger than before, but also more resistant, with complex geometries and shorter development times. This is precisely where a project at the Fraunhofer Institute for Laser Technology ILT, together with the L-40 powder manufacturer MacLean-Fogg and Toyota as the end user, comes in.
By using a gantry-based PBF-LB/M machine developed at the Fraunhofer ILT with a scalable build volume and the tool steel developed by MacLean-Fogg for additive manufacturing, very large die casting moulds with near-contour cooling could be additively manufactured for the first time – suitable for large-volume high-pressure die casting (HPDC) components.
Thanks to the gantry-based large-format system at Fraunhofer ILT, even complex, resistant tools with a volume of over 20 000cm³ can be printed reproducibly – a milestone for industrial applications in aluminium die casting. ©Fraunhofer ILT
Massive geometries previously led to residual stresses and critical defects in parts made with PBF-LB/M. As large casting processes are becoming increasingly established, the demands on the tools used in HPDC are growing. The moulds must repeatedly maintain precise component quality at very high quantities and withstand extreme mechanical and thermal loads. In order to ensure a sufficient service life of the tool inlays, they need complex, internal cooling structures, which cannot be made with conventional manufacturing processes.
Two key problems have so far limited additive processes from manufacturing such large-format die casting moulds: Firstly, the available construction volume of classic PBF-LB/M machines is too small to produce die or mould inserts with dimensions of 600 by 600mm² or more in one piece. Secondly, the tool steels used to date – in particular H11 (1.2343), H13 (1.2344) or M300 – cannot be processed reliably in this size range (>20 000 cm³). Even with optimum parameters, there is a risk of cracking, thermal distortion and inadequate mechanical properties.
The additively manufactured aluminium die cast tool is part of the tool for the transmission housing of the Toyota Yaris hybrid vehicle. It was chosen due to its size and the challenges of soldering and high maintenance time. ©Toyota Europe
This applies both during laser-based build-up and during downstream heat treatment. The greater the temperature gradients within the component during the manufacturing process, the greater the risk – an effect that is particularly pronounced with large-volume workpieces.
“To overcome these limitation, we need a new generation of machines and materials specifically tailored to the requirements of large-format HPDC tools,” explains Niklas Prätzsch, Group Leader LPBF Process Technology at Fraunhofer ILT. “It was precisely this combination that was the subject of the latest changes we have implemented.”
The new material and machine technology makes it possible for the first time to produce large-volume tools with a free-form cooling structure. This not only allows local temperature peaks in the casting process to be reduced in a targeted manner, it also increases the number of variants while simultaneously increasing service life. This means that different components can be manufactured on one tool platform without having to produce new tools each time.
To read the full article visit:
https://www.ilt.fraunhofer.de/en/press/press-releases/2025/9-10-am-die-casting-tool.html
For further details contact the Fraunhofer Institute for Laser Technology ILT or visit www.ilt.fraunhofer.de
