How Inert Atmospheres Add Value to Preparation & Storage of Metal Powders

As more additive manufacturers are relying upon metal powders to build next-generation tooling and equipment, it’s important to understand that these powders deserve extra care and attention - before, during, and after 3D printing is completed. Carrying on from our last blog update that explained how air-free atmospheres benefit the overall 3D-printing process and 3D-printing operators, this blog update focuses more on metal powder handling in an effort to help additive manufacturers create stronger products, reduce waste, and increase total life cycle of their powders.

To start, it helps to know that a consolidated mass of metal powders is inherently prone to contamination from water and oxygen, because these elements - typically found in any under-protected facility space - can easily permeate and occupy the small gaps between individual metal powder particles. If left in this unstable state, the contamination can degrade the overall quality of the consolidated mass of powder, which can potentially lead to a finished product that is less than perfect and may not hold up in real-world conditions.

For example, moisture trapped in a 3D-printed product is known to result in scattered porosity and the release of hydrogen during the melting process, eventually causing hydrogen embrittlement. No one wants that, particularly in the medical device and aerospace industries that are routinely using 3D-printed parts in life-or-death situations! Keeping powder particulates within a controlled atmosphere also eliminates airborne-related dangers, such as user health risks, damage to area electronics, and fire hazards associated to the combustibility of air-sensitive, fine metal powders. For all these reasons, metal powders deserve greater attention during handling steps of sieving, storage, and characterization.

Sieving in an inert environment
Since 3D-printing parameters generally call for specific powder particulate sizes, it’s common for additive manufacturers to incorporate a sieving station to weigh, measure, reclaim, and transfer powders - until the desired size distribution of particulates is achieved. By sieving in an inert environment, there is no oxygen or moisture to become trapped in between the particles, thus reducing contamination and removing the need to de-gas the powder before using it. This easily maximizes production efficiency by saving time and steps!

Humidity-free powder characterization for precise flow ability
While many manufacturers understand the importance of identifying irregularities in powder to attain powder conformity, some overlook the effect of humidity on flow-ability if benchmarking occurs in uncontrolled lab conditions. Understandably, the particulates of water vapor found in the air we breathe are easily overlooked, but missing the presence of humidity during characterization can wreak havoc on the benchmarking and characterization of powders and powder flow ability. Therefore, powder characterization should take place in an inert atmosphere, or a dry room, to remove humidity from the flow-ability equation and act as a representative environment for what the powder would see in the build chamber.

Storage in a controlled environment for long-term purity
When storing metal powders for future projects, additive manufacturers should want some assurance that the powders will remain in the purest form. After all, metal powders aren’t cheap! Unless properly protected during storage, oxygen, moisture, and any other forms of airborne, unwanted contaminants (organics, dust, sand, etc.) can easily permeate the powders over time, eventually rendering the powders useless, or requiring costly tracing and removal steps. To maintain long-term purity, it’s best to protect the powder investment by choosing a hermetic glovebox solution, or a hermetically sealed storage container - like those offered by us at Inert.

If you have any doubt about the quality of your powder handling procedures, learn more about Inert’s comprehensive solutions at www.inert-am.com.