Additive manufacturing (AM) has grown far beyond its origins in rapid prototyping, and is now used to produce a range of high-performance products and components. As well as offering material and energy efficiencies beyond traditional methods, AM enables the creation of multi-material objects with complex internal geometries.
Computed tomography (CT) plays a key role in the development of AM processes by enabling the complete 3D visualization of additively manufactured parts.
Understanding Additive Manufacturing
Most ‘traditional’ machining techniques can be considered subtractive. Milling, turning, drilling – all of these involve the removal of material from bulk solid in order to leave behind useful products (and, generally, wasted material in the form of offcuts and shavings).
Additive manufacturing (AM) is a departure from these traditional techniques. Rather than taking material away to carve out products from a larger piece, AM methodologies instead build up products through the controlled deposition of material.
3D printing technologies are at the heart of AM techniques, so much so that the two terms are often used interchangeably. However, there is a distinction.1 While 3D printing is necessary for AM, it is also commonly used for rapid prototyping and construction of one-offs and mock-ups.
The term 'additive manufacturing' refers exclusively to the use of 3D printing technology (and other techniques) for manufacturing: the creation of functional and usable products.
As 3D printing technology continues to evolve, additive manufacturing becomes increasingly versatile. As well as reducing material waste, AM techniques enable the construction of complex geometric shapes that would require multiple distinct processing steps and/or highly specialized production methods.
Additive manufacturing can also reduce the weight of components, and offers significant economic advantages for small unit volumes.2,3
The combination of precision, speed, affordability, and freedom of design means that AM is increasingly being used for the production of high-performance components; especially in aerospace applications where it can be used to produce porous or hollow-chambered components with drastically reduced weight.4–6
Developing New Additive Manufacturing Processes with Computed Tomography
The development of new applications for any technology requires accurate metrology. AM is no exception. Any defects in additively manufactured components must be reliably identified and accurately characterized to develop new AM processes and applications.
AM has special metrology requirements compared to other manufacturing techniques. AM involves the fabrication of 3D components either ‘from the ground up’ or ‘from the inside out.'
While this enables the construction of objects that comprise multiple materials or feature complex internal geometries, it also means that any metrology technique for additively manufactured parts must take into account the interior of objects and the surfaces.
Computed tomography (CT) has emerged as the best method for doing so.7 Computed tomography is a method of forming 3D representations of objects by taking many 2D X-ray images of an object around an axis of rotation. These 2D 'slices' can then be assembled into a 3D model using software.
Such visualizations enable a much clearer interpretation of internal structures than 2D techniques, which typically don’t offer sufficient detail of internal structures. Crucially, CT is completely non-destructive too.
CT scans of AM parts are enabling the refinement of existing AM processes as well as the development of new ones. For example, performing a CT scan of a particular component and comparing it to the original design enables manufacturers to determine the precise correlation between the schematic and the finished product.
Manufacturing artifacts or flaws can be easily identified and then corrected by making design or process adjustments.
CT Solutions for Additively Manufactured Components
With over 30 years of research and development in industrial X-ray testing, North Star Imaging is a world leader in 3D computed tomography systems. As well as offering a complete range of precision X-ray systems, we also offer comprehensive CT scanning services via our Inspection Services Group (ISG).
To find out how CT could revolutionize your AM processes, get in touch with a member of our team today.
- Additive Manufacturing and 3D Printing Are Two Different Things. https://www.additivemanufacturing.media/articles/additive-manufacturing-and-3d-printing-are-two-different-things.
- Joyce, J. Additive manufacturing paths to performance, innovation, and growth. (2012).
- Wong, K. V. & Hernandez, A. A Review of Additive Manufacturing. ISRN Mechanical Engineering 2012, 1–10 (2012).
- Schulz, B. Additive Technology Delivers Small Satellites to Space. (2019).
- Boen, B. 3-D Printed Rocket Parts Rival Traditionally Manufactured Parts. (2015).
- Dehue, R. The Possibilities of Weight Reduction With Additive Manufacturing. (2016).
- Thompson, A., Maskery, I. & Leach, R. K. X-ray computed tomography for additive manufacturing: a review. Meas. Sci. Technol. 27, 072001 (2016).
This information has been sourced, reviewed and adapted from materials provided by North Star Imaging, Inc.
For more information on this source, please visit North Star Imaging, Inc.