Building the Next Generation of Quality Additive Manufactured Products with Micro CT

Additive manufacturing (AM), sometimes referred to as 3D printing, is believed to be one of the greatest opportunities of our era and has the potential to completely change many business landscapes in the coming years and decades. There are still constraints and challenges in AM that need to be tackled by the combined efforts from scientists, engineers, and decision makers. During this process, with the help of X-ray imaging products and expertise, we can assist you to design, optimize, and build the next generation quality products using this fascinating additive manufacturing technology.

Defect detection
Traditional X-ray radiography has been used to detect the internal defects, such as pores and foreign objects (inclusions) in casting samples. With 3D Computed Tomography (CT), the detectable and distinguishable levels of variation in the sample have been greatly improved, so we can even see the partially fused regions in some AM parts.

Dimensional conformation
AM is all about building a product directly from a 3D model and this 3D model can have a very complex geometry as a results of advanced design methods such as 3D topology optimization, free materials simulation, or customer tailored medical implants design.
High Resolution X-ray microtomography (micro-CT), which can non-destructively and non-invasively image the object in 3D, is naturally the technique of choice in terms of checking dimensional (especially internal dimensions) faithfulness of AM products to its original design.

Apart from taking measurements from the 3D images, one common and quick assessment is to digitally register the scanned volume image to the original CAD model (with or without reference features) and then the variations between the two can be highlighted and quantified in 3D.

Raw materials control
In powder bed based AM techniques, such as SLM and EBM, the quality of the raw metallic powders is critical to the build quality of the final part. With high resolution CT, we can non-destructively characterize the metallic powders of its size distribution, measuring its sphericity which greatly determine the overall flowability, and also check whether there are hollow particles and inclusions in a testing batch.

Process optimization
In AM process, even for an identical CAD input, many manufacturing parameters can significantly affect the morphology and quality of the final part. These parameters include but are not limited to CAD orientation, laser scanning path, laser power and exposure time, pre and post heat treatment etc. Using micro-CT and specially designed software, we will be able to track tiny variations from the parts when tuning these parameters, hence be able to assist the designer with process optimization.

Volume based simulation and further analysis
Industrial X-ray CT can turn a real part into a detailed 3D computer model. Compare to the design CAD model, this scan-derived model can provide more information such as part morphology, surface roughness, and internal defects therefore it can be turned into a much more realistic models for finite element analysis and computational fluid dynamics simulations.

With North Star Imaging’s unique 4D imaging capability, we can even monitor and then quantify the behavior of an AM part being used, tested and imaged at same time using our X-ray CT scanners.

Conclusions
X-ray imaging techniques, 2D radiography and particularly 3D CT, are very powerful and useful tools to help develop, optimize and validate additive manufacturing technology and products. We believe a combined imaging and analysis solution will equip you with the best tool to be successful in this fast growing area.