HAMR and Freemelt show tungsten 3D printed rounds at MILAM2025

At MILAM2025, HAMR Industries and Freemelt AB unveiled some of their latest advancements in additive manufacturing with tungsten. Among the highlights were several as-printed penetrator rounds, fresh off the Freemelt One EB-PBF system at Neighborhood 91.

Tungsten is one of Freemelt’s three primary focus materials, alongside titanium and copper. Known for its extremely high melting point of 3422 °C—the highest of all metals—tungsten is an ideal candidate for high-temperature applications. Its superior stiffness and strength at elevated temperatures further enhance its appeal. Yet, this same high melting point and poor machinability present significant challenges when manufacturing pure tungsten or its alloys through traditional methods.

Electron Beam Powder Bed Fusion (EB-PBF) offers a promising solution. With its ability to melt materials at high temperatures and maintain controlled thermal environments, EB-PBF excels in producing crack-sensitive components through precise thermal management.

Tungsten has a host of other valuable properties. It exhibits a low coefficient of thermal expansion, high thermal conductivity, low vapor pressure, and exceptional resistance to radiation. These characteristics make it indispensable in applications like incandescent bulb filaments, electron emitters, X-ray generator targets, and radiation shielding. Additionally, its resilience in extreme conditions places it at the forefront of materials used in nuclear fusion reactors, particularly for plasma-facing components.

Traditional manufacturing processes such as casting, forging, rolling, joining, and machining fall short when it comes to tungsten, especially since the material tends to be brittle below 300–600 °C. These hurdles and the enhanced design freedom additive manufacturing offer have sparked intense research into AM for tungsten. Despite this, laser beam powder bed fusion (LB-PBF) has shown limited success, primarily because it typically operates at process temperatures around 200 °C. Producing fully dense and crack-free bulk tungsten parts with LB-PBF remains unachievable.

EB-PBF operates in a vacuum and consistently maintains process temperatures above 1000 °C. The electron beam’s inertia-free deflection enables speeds exceeding kilometers per second, allowing efficient melting of even the most crack-prone materials while preserving chemical purity. Recent studies have demonstrated that tungsten can be printed with full density and without cracks by using EB-PBF at sufficiently high temperatures to keep the material ductile.

At Freemelt AB, process parameters have been tailored specifically for the industrial system, eMelt, to facilitate additive manufacturing of high-quality tungsten components. Notably, tungsten remains a cornerstone of Freemelt’s material portfolio, along with titanium and copper.

The microstructure achieved in EB-PBF-processed pure tungsten at Freemelt showcases a dense, crack-free profile. While earlier studies typically used line melting strategies, Freemelt is now also experimenting with spot melting approaches, enabled by their proprietary Pixelmelt® software. Spot melting allows for higher beam power utilization, potentially enhancing the productivity of tungsten part fabrication.

Freemelt’s electron beam source is a diode type equipped with a laser-heated cathode. This design ensures consistent beam spot quality across the 0–6 kW power range. In contrast, other systems often suffer from degraded spot quality when operating above 2 kW.

This unique beam source configuration enables the EB-PBF process at Freemelt to harness high power during the preheating or thermal management phases and throughout the actual melting phase. The ability to use such high power levels for EB-PBF melting is unprecedented. A comparison between Freemelt’s melt settings for crack-free pure tungsten and those reported in literature underscores the novelty and effectiveness of their process window—one that fully exploits the advanced capabilities of their electron beam technology.