The most persistent myth about Electron Beam Powder Bed Fusion: “Smoke”
Myths exist in every business, and you are probably familiar with many of them. In this article, we address the most persistent E-PBF myth of them all. It is a phenomenon called smoke, which was an obstacle twenty years ago, in the early days of E-PBF development. Since then, several great solutions eliminating smoke have been developed and verified. Smoke has not been an issue for many years, but from time to time, people still claim that E-PBF builds are frequently plagued by smoke. They are unwittingly nurturing a myth. Let’s sort things out!
What is smoke?
The discovery of smoke originates back to the University of Leuven in Belgium in 1991, where PhD student Bart Van Der Schueren directed an electron beam towards a metal powder bed and immediately observed a big powder cloud levitating above the powder bed. He commented in his PhD thesis that “powder particles are blown away by EB, probably caused by electrostatic repulsion”. To our knowledge, this was the pioneer experiment with an electron beam as the energy source in additive manufacturing.
ProHeat® – Our solution
Freemelt offer a patented an indirect preheating method called ProHeat®. It is based on a hot graphite plate that swings over the powder bed. The graphite plate is heated by the electron beam and transmits the heat to the powder bed through infrared radiation. Thus the powder is never exposed to electrons during preheating, eliminating all risks of smoke. ProHeat® is a fully developed solution integrated in all Freemelt machine models. Read more here: Freemelt ProHeat®.
Conclusion: Smoke belongs to the past!
Electrostatic powder charging creating the powder cloud known as smoke was indeed a challenge 20-25 years ago, in the early days of Electron Beam Beam Powder Bed Fusion. But the smoke problem has been solved since long by various technology innovations. Today, several suppliers can offer E-PBF machines and processes that are 100% smoke-safe and very stable.
At Freemelt, we are regularly processing tungsten, copper and titanium alloys, powder materials with very different behaviors and processing requirements, and we never experience smoke with these materials.
