Smart Fusion Replay: Changing Additive Manufacturing With Deterministic Excellence

July 11, 2025 | Reading time: 7 min

Additive Manufacturing (AM) is no longer a futuristic dream; it's a present-day reality, transforming how we design, create, and deliver parts across myriad industries. At EOS, we’re constantly pushing the boundaries of what's possible with AM.

Our Smart Fusion technology has already been a game-changer, intelligently managing heat distribution during the build process to reduce supports, shorten build times, and cut costs.

However, for industries with the most stringent qualification requirements, such as aerospace and medical, the adaptive nature of Smart Fusion presented a unique challenge. Today, we're thrilled to discuss a groundbreaking advancement that addresses this: Smart Fusion Replay.

The Power of Smart Fusion: A Quick Recap

Before we explore Smart Fusion Replay, let's revisit the innovative leap that Smart Fusion represents. Introduced with Software Edition 05.23, Smart Fusion is an intelligent software solution that utilizes a feed-back control mechanism.

Unlike conventional feed-forward control, Smart Fusion employs EOSTATE Exposure Optical Tomography to monitor the melt pool and heat distribution layer by layer. This allows for real-time, localized laser power correction factors, ensuring optimal energy input throughout the build process.

The benefits are significant:

• Drastically reduced support structures: Often by more than 80%.
• Shorter build times: Reductions of over 20% are common.
• Lower cost per part: Approximately 34% cost reduction.
• Improved thermal management: Leading to better part quality and the ability to build complex geometries that were previously challenging.

For example, in the production of an IN625 impeller, Smart Fusion led to a 55% reduction in printing time and a staggering 95% reduction in support removal time, all while achieving a defect-free microstructure. Similarly, for a turbo housing, Smart Fusion enabled an 87% support reduction and an 11% reduction in build time.

The Qualification Conundrum in Regulated Industries

While the dynamic adjustments of Smart Fusion offer clear advantages, they also pose a hurdle for highly regulated sectors like aerospace and medical.

These industries demand processes that are not only robust but also stringently controlled and entirely repeatable with non-deterministic outcomes.

An adaptive process, where parameters might change from build to build (even if to optimize), can complicate qualification, as it introduces variability that’s difficult to document and certify against exacting standards.

In the past, the core challenge was that a Smart Fusion job, by its adaptive nature, couldn't easily be qualified under these strict regimes.

Introducing Smart Fusion Replay: Determinism Meets Optimization

This is precisely where Smart Fusion Replay steps in, offering a sophisticated yet simple solution.

Introduced with Software Edition 05.24, Smart Fusion Replay enables our customers to harness the full power and benefits of Smart Fusion while adhering to the rigorous qualification rules of regulated industries.

The fundamental principle of Smart Fusion Replay is to capture the optimized laser power parameters from an initial Smart Fusion build and then "freeze" these corrections. This "frozen" set of parameters can then be reused in subsequent identical build jobs. Essentially, the first build acts as the pathfinder, where Smart Fusion dynamically optimizes the process. Smart Fusion Replay then records this optimized path, turning it into a fixed, repeatable roadmap for all future builds of that specific part.

This means that the ensuing production processes are no longer adaptive in the same way as the initial Smart Fusion job. Instead, they run with a pre-defined, optimized set of parameters derived from actual build conditions, ensuring that each part is manufactured with consistent quality and identical component properties.

How Does Smart Fusion Replay Work? A Simple Workflow

The elegance of Smart Fusion Replay lies in its straightforward workflow:

1. Initial build with Smart Fusion: The process begins by manufacturing the part using the standard Smart Fusion technology. During this build, the system dynamically adjusts laser power based on real-time thermal data, optimizing the energy input for each layer.
2. Extract and freeze corrections: After the successful completion of this initial build, the Smart Fusion laser corrections — the specific adjustments made throughout the process — are loaded into our data preparation software, EOSPRINT. These corrections are then "frozen."
3. Replay for serial production: This frozen set of optimized parameters is then "baked into" the job file for subsequent builds. These "Replay jobs" can now run without active Smart Fusion, meaning they operate as a standard, non-adaptive process but with all the inherent benefits and optimizations discovered during the initial Smart Fusion build.

The result is a standard process from a qualification standpoint, but one that incorporates the intelligence and efficiencies of Smart Fusion.

The Broader Impact on the Additive Manufacturing Industry

Smart Fusion Replay represents significant maturation for metal AM. It bridges the gap between the cutting-edge optimization capabilities of adaptive processing and the stringent process control requirements of industrial-scale production. This innovation allows businesses to:

• Accelerate AM adoption: By simplifying process qualification, Smart Fusion Replay lowers the barrier to entry for adopting AM in regulated fields.
• Enhance production efficiency: The combined benefits of reduced build times, less material waste (through support reduction), and less post-processing lead to significant efficiency gains.
• Increase design freedom: Engineers can design complex parts with increased confidence knowing that a pathway exists to manufacture them reliably and repeatedly at scale.

Smart Fusion Replay is compatible with a growing range of EOS systems and materials, including popular choices like Ti64, IN718, and AlSi10Mg on various platforms. It’s important to note that older systems may require hardware upgrades to harness the full capabilities of Smart Fusion and, by extension, Smart Fusion Replay.

The Future Is Optimized and Repeatable

Smart Fusion Replay is a testament to EOS's commitment to listening to our customers and innovating solutions that address real-world manufacturing challenges. It enables users to reap the substantial rewards of Smart Fusion — reduced supports, faster builds, lower costs, and superior thermal management — while simultaneously ensuring a stable, repeatable, and deterministic process suitable for qualified serial production.

This development is set to redefine how industries approach the qualification of additively manufactured parts, making AM an even more compelling option for critical applications. As we continue to gather more technical data and develop case studies with our partners, the full extent of Smart Fusion Replay's impact will become even clearer. For now, the message is unequivocal: the future of AM is not just smart; it's reliably replayable.

We invite you to connect with our experts to explore how Smart Fusion Replay can transform your manufacturing environment.