The challenges of standardisation, certification and qualification are significant for additive manufacturing. As Amanda Allison, Senior technical project leader at TWI Tells TCT, they’re also vital to ramping up adoption for critical enduse parts.
TWI is a leading independent technology and research organisation, which has provided knowledge and safety assurance for engineering, materials and joining techniques since 1946. It was the first organisation to receive a signed AM facility certification from Lloyd’s Register in the UK. This included the 3D printing by laser powder bed of stainless steel components.
“Ten years ago, the development of certification, qualification and standardisation frameworks was minimal because of the low readiness of both technology and industry. There was also no priority placed on their development,” Allison said, reflecting on the changing AM standards landscape. “However, as the technology develops and more parts are being manufactured and put into service, there is an increasing pressure to focus and develop these frameworks to ensure the quality and safety of AM products.”
In 2015, TWI embarked on a joint industry project with Lloyd’s Register to explore the certification of metal AM components for adoption in the energy and offshore sectors. TWI, as part of this collaboration, worked with Industrial Member organizations to test and certify demonstration parts for AM production. From this, a set of industry relevant AM certification guidance notes for AM processes (powder bed fusion by laser, electron beam, directed energy deposition by laser, and Wire + Arc-based AM) were created.
“The development of standards is making it easier for industry to look to adopt the technology, but I think there is still a lack of confidence in some quarters because AM can be very disruptive and is moving rapidly. It also does not have a strong timeline of certified parts,” Allison said. “With a strong catalogue of standards, it does help give industry confidence in the use of the technology, and importantly, it standardises the approach to the processes and procedures for implementation, regardless of who is using the AM technology.”
Allison continued: “We also see a lot more examples of international standards committees collaborating together, which helps eliminate duplication and maximise resources. This is especially important, because the landscape involves a huge number of stakeholders in multiple industrial sectors. Bringing expertise and knowledge together to harmonise the approach is something that I’ve seen develop quite rapidly in more recent years, and something I encourage.”
Allison highlights the role of ASTM, which published the first AM standard (in 2009), and ISO committees in the development of standards. But there are still gaps and barriers: the need to avoid repeated testing for parts which may only have minor design variations; standards that qualify different AM systems; and the implementation of digital certification and qualification.
“AM part certification can be quite costly and it can also be a difficult journey, particularly when trying to navigate the AM standards and certification landscape alongside trying to link up with existing industrial sector standards,” Allison explained. “I also think, for facility qualification, the development and use of digital workflows is paramount in order to reliably track all process steps that parts undertake, and to monitor and control progress to ensure alignment with procedures.”
Although AM frameworks are becoming more popular, a thorough understanding of all the steps and factors along the AM chain requires time and education. According to Allison, “when it comes to investing in AM, certification can often fall last on the list of priorities.”
“This can lead to problems further down the line,” Allison said. “For me, certification starts at the design stage. Organisations need to be looking into the requirements for certification at the beginning because it can have strong implications on the AM process chain.”
Frameworks are needed to support AM adoption, increasing part volumes, and distributed manufacturing.