Sabotaging metal additive manufacturing: Powder delivery system manipulation and material-dependent effects

Additive Manufacturing (AM) is a direct digital manufacturing technology increasingly used to manufacture functional parts for military and civilian applications. As AM becomes more integral to national security and economic prosperity, it also becomes an attractive cyber-physical attack target. In this paper, we focus on attacks aiming to sabotage metal parts produced using Powder Bed Fusion (PBF), a metal AM process used to manufacture near net shaped parts for safety critical systems. Specifically, we focus on the Powder Delivery System (PDS), an integral PBF subsystem. In our examination, we adopt the attacker’s perspective, identify possible manipulations which can be used individually or in combination to degrade part mechanical properties. We experimentally evaluate the impact of a selected manipulation on part fatigue life. Destructive testing on two different types of stainless steel specimens, 17–4PH and 316 L, confirmed effectiveness of this attack and revealed material-dependent impacts while non-destructive testing illustrated the difficulty in attack detection. Based on our analysis and experimental evaluation, we conclude that the investigated attacks have the potential to be effective against complex geometry parts such as those used in military and civilian systems while remaining undetected.