Additive Manufacturing (AM) is becoming more popular within the engineering industry as companies begin to consider it as a preferred method of component production, rather than just using AM for rapid prototyping.
Oxygen analysis used within the AM powdered metals process enhances both quality control and ensures safety within the manufacturing process. As many of the components produced by using the AM method are commissioned by the aerospace, defence and automobile industries, identifying and reducing the chances of oxidisation of the metal during the build process is therefore essential.
Any oxidisation occurring within the AM process can lead to build failures or components ultimately failing to meet the standards required due to stress test failure or density test failure. Interstitial absorption of any oxide embrittles the weld and may render the component useless.
When welding titanium, for example, the American Welding Society recommends measuring the argon shielding gas to ensure it is 99.995% pure with no more than 20 parts per million oxygen (AWS D1.9, Structural Welding Code—Titanium).
Similarly, but less stringent oxygen levels are also recommended for stainless steel, tungsten, aluminium and most nickel alloys. The measuring of the oxygen level within the additive manufacturing process is very critical to ensure the long term adoption of this technology.
The other critical reason to measure oxygen levels in the AM process, is to ensure the safety within the manufacturing process. All powders, including seemingly benign examples like flour or powdered milk, are highly flammable due to the large surface area to volume ratio. Therefore it is very important to ensure the level of oxygen within the AM process does not reach such a level to allow the powdered metals to combust. In summary, the measurement of the oxygen content within the AM process ensures no oxidisation occurs and eliminates the risk of explosion.
Cambridge Sensotec, manufactures of the Rapidox range of gas analysers, have been working with the leading AM machine manufactures to supply high performance oxygen analysers measuring ppm levels of oxygen within the process. The analysers are supplied as an OEM component to integrate seamlessly into the AM product.