A Liquid Cooled Cold Plate has been utilized in military and supercomputing applications since the 1970's. A Liquid Cooled Cold Plate removes high rates of heat with low fluid flow, and are now being used for high power electronic components such as insulated-gate bipolar transistor (IGBT), Diodes, Power Supplies, Capacitors, or radar electronics where sometimes kilowatts of power is needed to be removed.
Tubed Cold plates have copper pipes with typical diameters of 5/8”, 3/8”, or 1/4" that are mechanically sandwiched into an Aluminum machined plate, and either Epoxied, or Soldered in place. The fluid pipes have a number of loops designed into the plate to ensure maximum thermal uniformity. Radian Thermal Products liquid cooling systems typically use a pump to circulate fluid through cold plates and heat exchanger.
Another manufacturing method for a Liquid Cooled Cold Plate is to use Friction Stir Welding which is a solid-state joining process where the metal is not melted during the manufacture. Invented at The welding Institute (TWI) UK in December 1991, Friction Stir Welding is more of a forging process than an that uses a spinning pin and downward force to create a bond between two pieces. The joined material is plasticized by heat generated by friction between the surface of the plates and the contact surface. A Friction Stir Welded Cold plate offers a flexible high fluid path, and has the ability to join different alloys.
A Vacuum Brazed Cold Plate gives the highest fluid path, and is able to create features such as “islands” for through holes or other features. Vacuum Brazing uses two base metals that are joined together using a filler metal that has a lower melting point than the base metal. Vacuum brazing typically uses a furnace as several joints can be made at at the same time when the furnace reaches the brazing temperature. This method of manufacture is particularly suitable for dual sided liquid cold plate applications.Vacuum brazing offers significant advantages as it is extremely clean, and provides flux-free braze joints of high integrity and strength.
Turbulators are sometimes used to increase the thermal performance of tubed cold plates by creating a turbulent flow in the cooling fluid. There are many designs available in the market such as a spring turbulator, twisted tape turbulator, ball bearing turbulator, and matrix turbulator. Radian's thermal engineers can discuss with your team the benefits of each design.
Radian can also produce heat sink blocks with ultra fine internal fins that significantly enhance the heat exchange area for cooling fluids. All components of our liquid cooling modules are joined together using a one-step brazing process which helps provide leak free operation. This process is so reliable that we guarantee our liquid cooling blocks against leakage.