Assessing the quality of a tubed cold plate
High reliability is important, as a coolant leak can be catastrophic in a liquid cooling system. First examine the tubes; they can reveal a lot about the reliability of the cold plate. A cold plate that uses continuous tubing is inherently more reliable than one constructed from straight tubes connected by soldered joints, as any joint increases the potential for leakage.
Look also at the quality of the bends. If the tube is not bent carefully, the tube can be deformed. While this does not affect the reliability, it changes the cross-sectional profile of the tube, which can result in increased pressure drop and lower performance.
Finally, examine the cooling surface of the plate. For demanding applications, direct contact between the tube and the component is best. This means that the tube surface must be flush with the aluminum plate. A common manufacturing technique is to put an over-sized tube into a channel and machine off or fly-cut the top. This process, also known as skim cutting, thins the tube thickness at the place surface, which can increase thermal performance but if incorrectly executed, can compromise the structural integrity of the tubes. Eaton's design and manufacturing expertise minimizes structural risk while boosting overall tube liquid cold plate performance.
Another alternative is to embed the tube below the surface of the cold plate and add copper inserts to level the surface. This technique is both expensive and limits performance. The cooling tube is further from the components being cooled and the additional layer of epoxy required between the tube and the insert further decreases performance.
| Reliable | Unreliable | High performance | Lower performance |
| Continuous tube | Tube with joints | Epoxy-free construction | Inserts over tube to create flat surface |
| Flattened top surface | Skim-cut top surface | Tubes flush with surface of plate | |