Why CT scanning is becoming a key part of successful 3D printing21 July 2017
Once a print run has been completed, a proper quality inspection is essential. While effective data preparation and real-time monitoring of the printing process can help prevent errors before they occur, there are still a range of things that can potentially go wrong before or after printing. For one-off or limited-run parts, conducting a quality check manually is unlikely to prove prohibitively complex or time-consuming. However, for larger print runs, things become more complicated. That’s why more and more 3D printing teams and bureaus are incorporating CT scanning into their operation, either by outsourcing to CT specialists or investing in their own in-house equipment.
Exploring this technology has also opened up a new world of possibilities for 3D printing professionals when it comes to reverse-engineering parts. Once a part has been scanned, a precise picture of its geometries is created, which can then be converted into a suitable format for printing. This offers a huge advantage when it comes to recreating parts that cannot be broken down or damaged in any way, such as vintage car parts. The potential applications for a combination of 3D printing and CT scanning in this area are huge, and we’ll be looking at them in greater detail in a future blog post.
What is CT scanning?
Computed tomography — more commonly called CT scanning — is a useful tool for checking parts once a printing run has been completed. The process is related to medical CAT scans in that it utilises x-rays to build up a detailed picture of an object or body part’s interior. Industrial CT works by scanning the parts, then comparing the resulting files against the original CAD files to identify any discrepancies.
This turns quality checks for 3D printed parts into a completely hands-free process, freeing engineers from having to check each part individually and minimising the risk of complex and fragile parts being damaged through human error. Furthermore, as a non-destructive process, no parts need to be broken open to check the internal areas. It also can be applied to parts generated with any printing technology, in a range of materials, making it an incredibly versatile tool for AM professionals.
The part data that can be captured in this way includes:
- Wall thickness
- Geometrical tolerances
- Internal structures
- Cracks or knit lines
- Material flow (to identify bonding issues, etc.)
Where does this fit into project workflows?
CT scanning can be used as part of both prototyping and production applications. For functional prototypes, a CT scan can help identify any adjustments to the printer settings that will help avoid any errors and ensure the finished parts fulfil the project specifications to the letter. During the production process, it can be used to quickly identify any outwardly invisible mistakes or inconsistencies and dramatically speeding up the quality checking stage.
For multi-part prints, a separate scan should take place once the individual components have been assembled. This will ensure that all parts have been properly affixed to each other, identify any potential mechanical faults in moving parts, and ensure no part has been damaged during the gluing/welding process.
The value of strategic automation
We’ve talked a lot on this blog about the move towards automated processes in additive manufacturing. While we’re still a long way from seeing CT scanners become a part of every 3D printing team’s in-house tools, due to the size of the equipment and the investment involved, the number of companies exploring their usage is definitely a positive sign.
More and more 3D printing production operations establish themselves, we expect new scanning solutions to arise in response to this. This, in turn, will lead to more efficient processes, with no compromise on the quality of printed parts delivered to customers.
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