Sandia National Laboratories physicist Willis Whitfield, 92, passed away earlier this month and left a technological legacy that continues to reverberate today: The legendary clean room.
The original laminar-flow 10 x 6 clean room developed 50 years ago by Whitfield was more than 1,000 times cleaner than any cleanrooms used at the time and ultimately revolutionized microelectronics, healthcare and manufacturing development. According to Sandia, with slight modifications, it is still the clean room standard today. And one other thing: the invention lead Time magazine in 1962 to dub him "Mr. Clean."
"His breakthrough concept for a new kind of cleanroom, orders of magnitude more effective than anything else available in the early 1960s, came at just the right time to usher in a new era of electronics, health care, scientific research and space exploration. His impact was immense; even immeasurable," said Sandia President and Labs Director Paul Hommert in a release.
According to Sandia, the problem Whitfield and his team at the time were trying to solve was removing dirt and dust particles that were interfering with the lab's nuclear weapons development.
According to Sandia: "Whitfield looked at blowers, vents, grading and the cost per square foot to build his invention, so it would be something people could afford. By the end of 1960, Whitfield had his initial drawings for a 10-by-6 cleanroom. His solution was to constantly flush out the room with highly filtered air. In that first model, Whitfield designed a workbench along one wall. Clean air entered the room from a bank of filters that were 99.97% efficient in removing particles larger than 0.3 microns. For example, cigarette smoke blown in one side comes out the other as clean air. The air is circulated in the room at a rate of 4,000 cubic feet or about 10 changes of air per minute, an amount of air movement that is barely perceptible to the workers inside. The linear speed of air is slightly more than 1 mph, which is about the same as that felt walking through a still room. In a later modification, the air was passed down over the work area instead of across, getting an assist from gravity in carrying troublesome particles into the floor, which was covered with grating. Filters underneath clean the air and it is circulated back around to re-enter the room. The constant flow of clean air performs a sweeping function."
When the first cleanroom was tested "the dust counters went to nearly zero. We thought they were broken," Whitfield said in a 1993 interview. According to the Sandia release, some manufacturers thought the clean numbers so unreal they accused Whitfield of perpetuating a hoax. Of course it was anything but and the $50 billion of clean rooms were sold in a few years, Sandia stated.
RCA and General Motors were early adopters of the cleanroom and Whitfield eventually worked with NASA to provide planetary quarantines during missions to the moon and Mars and spacecraft sterilization techniques.
Cleanrooms and clean benches based on Sandia's design are still used in the manufacture of precision mechanical assemblies for systems designed at the national security laboratory, Sandia said.
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