Re-envisioning Metal 3D Printing: Breaking the Boundaries of Manufacturing

Imagine unpacking a metal job with the ease of handling a polymer job – a feature that was once thought impossible. Our incredible Innovation Team made the impossible possible – again! 

In metal 3D printing, supports are considered a necessary evil. They act as heat sinks to draw heat away from the melt pool, anchor parts to the build plate to prevent distortion from internal stresses, and maintain the part's position during printing while absorbing recoating forces. However, the downside is that every cubic millimeter of printed support structures brings various challenges and complexity. Designing and optimizing support structures takes time, adds to the printing duration, results in wasted materials, often requires manual labor or CNC machining for removal, and leaves supporting marks on the part's surface, necessitating post-machining. Printing entirely without support structures proves to be a formidable challenge in metal 3D printing. In EOS's metal 3D printing, the laser is the primary source of energy deployed into the powder bed. The platform or powder bed is pre-heated to a maximum of 200°C, creating a significant thermal delta between the liquidus state and powder, inducing stresses during material shrinkage after cooling.  

The exposure parameters and the printing system itself can lead to an inhomogeneous remolten surface, acting as a catch for recoating forces that may rip the built structure from the powder bed. The innovative team at EOS addressed these challenges by working on multi-exposure parameters and strategy optimization, individually tackling the effects mentioned above, emphasizing the need for support structures to make the lives of our customers easier, and aiming to bring the cost per part down significantly. 

Significant reductions in laser-to-laser time have been achieved, facilitated by the system's streamlined process, requiring only the replenishment of fresh powder. This advancement enables swift restarts, minimizing downtime and maximizing productivity. 

Cost reductions are attainable through the elimination of the need for part separation from the building platform. Previously, operations such as band saw or wire EDM were required, contributing to both time and material waste. Additionally, the need to refurbish the platform by grinding it flat again is rendered unnecessary, further saving on maintenance costs. With the elimination of the task of replacing the building platform inside the machine, time efficiencies are optimized, allowing for seamless workflow continuity. 

In conjunction with EOS's proprietary Smart Fusion technology for optimized heat management, a job could be printed entirely “free-floating” in the building process chamber without a single support. The "micro impeller" was chosen as an ideal reference geometry due to relatively low stresses during printing, making it a perfect showcase. Not only can it be spun like a top, adding a fun factor, but the working principles of these improvements can be applied to various geometries and applications, provided the part can be oriented starting from a relatively small section in the X/Y-plane. 

This principle can be implemented across different industries where applications meet the above mentioned criteria. One can envision its application in automotive superchargers, for instance, with impellers. 

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