The powder chain goes hand-in-hand with the AM processing chain. It is a reciprocal and interdependent relationship whereby powder properties impact on the processing characteristics (spreading, melting…) and where, in return, the processing steps and efficiency affect the powder characteristics.

This close intertwined relationship complicate the control of the AM process and  can dramatically influence the final components properties or the recyclability efficiency of the powder.
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So how do you prevent powder contamination or properties variations?

Metal powder costs will be the biggest continuous expense through the life of an AM machine [1]. Under these circumstances, a customer has a number of considerations to make when defining powder requirements and deciding where to procure it.

​Post-build hot iso-static pressing (HIP) has become a common practice for the closure of some types of defects in AM metal components. Assuming your products lend themselves to HIPing, can this post-processing method get rid of all porosity?

Some defects found in parts built using AM are related to processing parameters or to the composition of alloys optimised for more conventional, slow-cooling manufacturing process. These defects – such as porosity or cracking – can sometimes be healed by post-processing such as hot isostatic pressing (HIP). Yet, the formation of pores during AM is also linked to the quality of virgin powder.

Powder bed fusion additive manufacturing promotes material efficiency as a unique selling point. Unfused particles are in effect recyclable after processing operation and reused [link]. Powder characteristics however tend to vary following different stages of the AM process and these variations could affect powder behaviour and final part quality. Specifically, feedstock quality must be tightly controlled due to their influence on powder flow and packing density.