Component-side flat heatsinks for printed circuit board (PCB) assemblies are often used in applications where ambient heat could affect the performance or cause the failure of critical electronic systems. Photo etched flat heatsinks also save space and weight compared to vaned heatsinks. Heat sinking is also gaining applications around high-power semiconductor processors.
Photo etching is particularly effective in fabricating PCB heatsinks because the process can produce complex geometries far more readily than punching, laser, or wire EDM. Inexpensive phototooling can be produced for nearly any geometry.
Although many heatsinks are produced in aluminum due to light weight and cost, copper is a substantially more efficient conductor of heat. The rate of thermal conductivity is expressed in watts/meter*Kelvin (W/m*K). The rate for pure aluminum (1100 series) is 247 and the rate for copper is 398, nearly 60% greater conductivity. Only silver at 428 and diamond at an astounding 2500 watts are more effective than copper.
Many avionic heatsink applications demand the lighter weight of aluminum. All other things being equal, a copper heatsink will be three times heavier than an aluminum one.
Conard photo etches aluminum up to .080” thick. We also routinely etch copper heatsinks that are up to .063” thick. Dimensional tolerances at .063” will run +/-.012”.
For ball park purposes, photo etching 12” x 12” x .062” heatsink blanks in 100 piece lots will be in the $30 range for aluminum and in the $50 range for copper.
Chemical etching also offers the advantage of being able to create additional surface area by etching patterns into the radiating side at no additional cost.
In addition to providing basic photo etched flat blanks, Conard is AS9100/ISO9001 registered and has more than 20 years of experience in producing complete heatsink assemblies that can include secondary machining, surface finishing such as conversion coating for aluminum and nickel plating for copper, installation of hardware and screen printing of nomenclature. We can also provide thermally conductive, electrically insulating conformal coating in accordance with MIL-E-5272.