Creating clean room technology
SURVIVING THE TEST OF TIME — In a 2008 photo, Willis Whitfield stands outside a clean room at Sandia’s Microsystems Engineering, Sciences and Applications complex. (Photo by Randy Montoya)
Willis Whitfield was, by all accounts, a simple and humble man. Raised on a cotton farm in West Texas, he knew how to work hard and solve problems, from fixing tractors and other machinery, to inventing equipment when he couldn’t find something that fit his needs. That ingenuity led Whitfield, a longtime physicist at Sandia, to create advanced clean room technology that is still in use today.
The problem at hand
In 1959, there was a common problem affecting the manufacturing of complex parts, including nuclear weapons components. They didn’t work because there were particulates in them. Because Sandia needed the parts for weapons going into the stockpile, and its mission includes pushing the boundaries of science, engineering and technology, it set out to solve the problem. First, the Labs assembled a team from the advanced manufacturing section, which included Whitfield, to look at the issue.
An idea sketched out on a tablet
A SIMPLE DESIGN — Willis Whitfield’s sketch of a clean room, created while on an airplane in 1960. (Photo courtesy of Sandia)
The team spent the next few months traveling to various manufacturers to see the problem firsthand, along with the clean rooms they had at the time. Those clean rooms were not so clean. Tests showed one of the best clean rooms of the period averaged more than a million particles per cubic foot of air.
On the way home from one of those trips, Whitfield had an idea. “He was on an airplane, and he whipped out a tablet and basically drew out the whole schematic of how the clean room should work,” said Whitfield’s son Jim, who was 6 years old at the time. “It was just a simple sketch. It just took a few minutes, and it’s the basic principle that is still used today.”
That principle is called laminar-flow, or the constant sweeping of a room with highly filtered air. As Whitfield once said, “It’s letting the air be the janitor.” The process involves pushing particles to the floor, filtering them and circulating them back into the room with a constant but very slow movement of air. Data collected on Whitfield’s 1961 prototype showed an average of 750 dust particles per cubic foot of air — 1,000 times cleaner than clean rooms in use at the time.
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