3D printer manufacturer 3D Systems has collaborated with the European Organization for Nuclear Research, CERN, and the Dutch National Institute for Subatomic Physics, Nikhef, to 3D print cooling components for the Large Hadron Collider (LHC).
Specifically, the partners used the company’s DMP Flex 350 PBF system to print a set of custom titanium cool-bars for use in particle detection experiments last year – components that would otherwise be impossible to manufacture. As a testament to its contributions, 3D Systems was even awarded the LHCb Industry Award in late 2019.
Sub-zero environments in the LHC
The LHC is the largest particle accelerator in the world, and is used by CERN to study high-energy particle collisions. It stretches 27km in length, and enables collision observations to take place at four beam intersection points, each of which contains advanced large particle detectors.
In the detection portion of the LHC beauty (LHCb) experiment, specifically, a thin 140m-long photon-detector strip must be cooled to -40˚C to preserve the reaction long enough for it to be studied. This strip is less than 2mm in width, and requires titanium cool-bars to perform 100% of the necessary cooling action. Seeing as the bars must dissipate a large amount of heat uniformly in a very limited space, the precision and efficiency of their design was of the utmost importance.
The initially proposed design was determined to be impossible to manufacture using conventional methods. To maximize efficiency, the bars needed minimal material between the coolant inside and the outer surface, so a wall thickness of 0.25mm was crucial. Unfortunately, this specification proved too difficult to machine for a bar of length 263mm.
3D printing the titanium cool-bars
After an intensive trial and error phase, CERN eventually turned to 3D Systems and its metal additive manufacturing technology. Antonio Pellegrino, a Project Lead at CERN under the LHCb experiment, states: “Out of a few possible companies, we chose 3D Systems because it seemed to me that the engineers there were capable of actually transforming our design into something that could be produced.”
Working with 3D Systems’ application engineers, the CERN team modified their bar designs to be 3D printable, all while retaining their precise functionality. A wall thickness of 0.25mm was eventually achieved, as well as a leak-tight geometry made of 3D Systems’ high strength LaserForm Ti Gr23 powder. The final design comprised mirrored A and B components that were welded together, and required minimal manual assembly. The bars were also redesigned to feature parallel cooling channels, ensuring 100% powder removal during post-processing.
Based on the results of a set of stress tests, the partners expect the bars to last at least ten years. This figure is further reinforced by the fact that the components required almost no assembly, and were created in an optimized form using one material.
With a field as nuanced as thermodynamics, the precision of a part’s geometry is as important as ever. Earlier this year, a team of mechanical engineering students at Purdue University designed a highly-efficient, award-winning 3D printable heat sink. The advanced design took the #1 spot at the Virtual Student Heat Sink Design Challenge, and contained Formula-1 and sharkskin-inspired internal channels.
Elsewhere, GE Research, the R&D wing of American conglomerate GE, has previously used 3D printing to create an ultra-efficient, low-emission heat exchanger for power generation equipment. Dubbed UPHEAT (Ultra Performance Heat Exchanger enabled by Additive Technology), the device was developed as part of a $2.5M research project.
Looking for a career in additive manufacturing? Visit 3D Printing Jobs for a selection of roles in the industry.
Featured image shows the Large Hadron Collider. Photo via CERN.