The Structural Integrity of Additive Manufactured Components

Additive manufacturing (AM), also known as 3D printing, is the name for describing the manufacturing technologies that build 3D objects by adding layer-upon-layer of material.

Additive manufacturing represents a step change in the flexibility of production, allowing businesses to design and make better products, enter new markets and develop new business models, react more quickly to changing demands, and explore the possibilities of digital manufacturing.

Additive manufacturing can be performed with virtually any metal, but the most commonly used include aluminium, titanium alloys, stainless steel, nickel and cobalt-chrome. Each material brings its own challenges.

Considering that the majority of these materials can be processed using different methods such as laser metal deposition, selective laser melting, arc processes and cold spray, the microstructure and consequently build direction dependent material properties of additive manufactured components exhibit a wider variance compared to the properties of components manufactured by classical welding techniques. Additionally, each AM process creates a unique metallurgical structure, requiring a specific heat treatment to obtain the desired final component properties. The choice of optimal parameters for post-processing techniques poses another challenge affecting the integrity of the final component manufactured by AM.

Understanding residual stress states and the evolution of residual stresses during the build of additive manufactured parts is also essential to ensure safety. Considerable research effort has been devoted to engineering of tailored residual stress fields but the control of distortion and residual stresses is very strongly linked with the process and subject of various on-going research programmes.

Additive manufacturing is certainly being used more widely in various industries but not yet heavily used for production. There is considerable research and development work aimed at trying to perfect and understand the various additive manufacturing techniques, examine the relationships between the powder-process-propertiesperformance, and explore the manufacture of a complex, integrated system. There are still many questions that need to be addressed before additive manufacturing can be utilized in a production mode for critical, load bearing applications.

In order to address issues like these for companies considering additive manufacturing in critical engineering applications, FESI will be holding a one-day workshop dedicated to the structural integrity of additive manufactured components. Delegates will be invited to participate in a discussion to identify challenges and express their view on the methods to ensure high integrity in safety-critical structures expected to bear loads. At the end of the workshop FESI would summarise the gaps in knowledge and possible ways that these could be addressed.