As power densities continue to increase, and coolant-based solutions are shunned because of cost / size / energy concerns, the electronics industry has become increasingly reliant on fans and the air flow they provide. This requirement is challenging as fans are a known reliability risk. A recent report released by Carnegie Mellon1 showed that fans were consistently in the top ten failure sites for enterprise applications.
The electronics industry has attempted to resolve this risk through standard test requirements. These are typically constant load tests performed at elevated temperatures (often at 70C) for long periods of time2. These tests are primarily designed to assess fan failures caused by loss or deterioration of the lubricant that leads to wear in the bearings. The viscosity of the lubricant depends on the operating temperature and can deteriorate rapidly at higher temperatures.
The response from the fan industry has been as one would expect. Fan manufacturers design products that pass the test. And some fans are very good at passing these tests (L10 greater than 100,000 hours at 40C). So, what’s the problem? Fans keep failing.