Atmospheric gases play a fundamental role across each stage of the additive manufacturing process – from metal powder production and storage to enhancing the printing process and post-printing cleaning.
The mechanical properties of a finished product are not only highly dependent upon the printing process itself, but the characteristics of the powder used in the process. The quality of metal powders used in additive manufacturing is critically important as it can impact on the physical properties of the finished product.
Gas atomisation is the most effective approach to metal powder production due to the superior geometrical properties achieved. It requires not only a large supply of inert gases such as argon and nitrogen, but the gas molecule expertise to help manufacturers fine tune the atomisation process to further improve powder characteristics, eliminate rejects – and to do so cost effectively.
Once the metal powders have been produced, it is essential to maintain the correct atmosphere during their storage in order to avoid humidity. The quality of metal powder has fundamental impact on the microstructure and physical properties of the printed item, so they must be of a defined and consistent quality, meaning that correct storage and handling is vital. Humidity will age the powder, reduce its flowability and will increase the amount of oxygen during printing.
Linde has developed an innovative solution to resolving this storage challenge – the ADDvance® powder cabinet. The powder cabinet works with a moisture control and monitoring unit to continuously measure humidity levels, triggering a high-volume purge gas flow as soon as the doors are closed to rapidly remove moisture in the air. It then applies a lower stream of gas to ensure a consistently low level of humidity, ensuring the quality of the valuable, sensitive metal powders is retained.