X-ray and CT technology is the leading method of quality assurance, but it is also being used for research into understanding how additive manufacturing process parameters influence defect formation in AM built parts. In his latest paper, Herminso Villarraga-Gómez explores the details.
Comparison of NDT techniques according to detectable defect location and their achievable spatial resolution - X-ray CT aids research into defect formation in AM parts.Additive manufactured parts and components can be difficult to qualify. They consist of very complex, free-form shapes with rough surfaces and internal geometry, as well as interconnected structures and channels. Whilst additive manufacturing provides a unique solution to many manufacturing problems, its drawbacks are well documented already. Parts can potentially contain voids and inclusions such as unmelted particles or powder residues. This is important, especially when AM parts are being increasingly used in life-critical applications. The channels or micro-structures in the powder material could potentially influence the porosity percentage of a metal AM part or induce fractures and cracks inside with the lack of fusion voids.
In assessing additive manufactured parts, vision and contact based inspection techniques simply cannot access the internal features. With the most concerning errors occurring inside their volume, this makes it a challenge for conventional NDT techniques such as ultrasonic, infrared, eddy current, radio-graph inspection and light based technologies to obtain a meaningful insight.
To achieve a comprehensive level of inspection for AM parts, these solutions cannot provide the insight required for complete quality assurance. However, with X-ray and CT, there are several advantages as a non-destructive method, for acquiring structural characterisation of both internal and external geometries of AM parts. It is often the only viable option to extract component dimensions of internal, hidden and obscured features.
Read Herminso Villarraga-Gómez's latest paper ‘The role of computed tomography in additive manufacturing’ to find out more.
Further reading on X-ray and computed tomography for additive manufacturing and 3D printing:
Discover Nikon Metrology’s additive manufacturing solutions or find out more about Nikon CT.
Take a look at the recent paper on 'Computed tomography metrological examination of additive manufactured acetabular hip prosthesis cups'.
Read more about X-ray and CT for additive manufactured parts in Herminso's previous paper 'X-ray CT: a powerful partner in the 3D printing revolution'.