On December 3, 2020, 3D printer manufacturer 3D Systems, in cooperation with the European Organization for Nuclear Research (CERN) and the National Institute of Subatomic Physics (Nikkef) in the Netherlands, produced 3D printed cooling components for the Large Hadron Collider (LHC).
They used the DMP Flex 350 PBF system produced by 3D Systems to print a set of customized titanium cooling rods for particle collision detection experiments. If 3D printing is not used, these parts cannot be manufactured. 3D Systems was also awarded the LHCb Industry Award at the end of 2019 for this contribution.
LHC is the world's largest particle accelerator, and CERN uses it to study high-energy particle collisions. With a length of 27 kilometers, it can observe collisions at four beam intersections, each of which contains advanced large particle detectors.
In the detection part of the LHC beauty (LHCb) experiment, a 140m long photon detection strip must be cooled to -40°C in order to maintain a long enough reaction time for research. The width of this test strip is less than 2mm, and a titanium cooling rod is required to perform cooling for it. In view of the fact that the cooling rod must dissipate a large amount of heat evenly in a very limited space, the accuracy and efficiency of the design are of vital importance.
Their original design cannot be manufactured using conventional methods. In order to maximize efficiency, these cooling rods require the least amount of material between the inner and outer coolant, so a wall thickness of 0.25mm is critical. Unfortunately, it turns out that this specification is difficult to process for bars with a length of 263 mm.
3D printed titanium alloy cooling rod
After a rigorous trial and error phase, CERN finally chose 3D Systems and metal additive manufacturing technology. Antonio Pellegrino, head of the LHCb experiment at CERN, pointed out: “Among some possible companies, we have chosen 3D Systems, and their engineers are able to transform our designs into products that can be produced.”
The CERN team worked with application engineers from 3D Systems to modify the cooling rod design to be 3D printable while retaining precise functionality. The result was a wall thickness of 0.25mm and a sealing geometry made of 3D Systems' high-strength LaserForm Ti Gr23 powder. The final design includes mirror A and B components welded together and requires minimal manual assembly. The bar stock has also been redesigned with parallel cooling channels to ensure 100% removal of powder during post-processing.
Based on the results of a series of stress tests, the team expects these components to last at least ten years. As there is almost no need for assembly, and parts are created in an optimized form using one material, the life span will be longer.