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 Peter
Engels's BEC machine in action: A disc-shaped magnet delivers
ultracold atoms to a high-vacuum chamber (at lower left of photograph).
A laser beam array is pictured at right.
 Technical Services director Lorie Druffel.
For his machine, Engels needed parts that let him manipulate
lasers and generate an extreme vacuum. It was a project just made
for the folks at tech services. Shop director Lorie Druffel shows
me around the instrument and electronics facilities. The Instrument
Shop is clean and quiet the day I visit. The staff—supervisor
Henry, John Rutherford, Lauren Frei, Dave Savage, and Steve
Watson—are taking inventory before the end of the fiscal year. They
have the best selection of pipes, rods, and plates of various
metals, woods, and synthetics in the region, says Henry. At one
side of the shop are desks where the staff design parts and
assemble small items. The main floor of the shop is crowded with
big machines, some of which I recognize—a drill press and a
lathe—and two of which I don’t. They’re bigger than a VW Beetle,
and have sliding doors almost large enough to step through. These
are the CNCs, or computer numerical control machines. The shop
first got small versions of CNCs five years ago. Today the
“Beetles” do most of the machining here.
While the CNCs are run by computers and machinists, the parts
they make still begin as an idea in a researcher’s mind.
“Sometimes we do the solution and the problem-solving with them,
and other times they know exactly what they want,” says Druffel.
Researchers come in with everything from a vague notion, to a
sketch on a napkin, to detailed blueprints. Everything—even the
detailed plans—gets a thorough review before going into
production.
It’s an evolving process in which scientist and shop crew
discuss everything from the overall dimensions of a part to what
material would be best to use. That's a big advantage over hiring
an outside shop, which would require a detailed plan to start with
and which would be less likely to make suggestions about such
things as which grade of stainless steel to use for a given
research application.
"We talk with them," says Henry. "Especially foreign students.
They know what they want, but it's kind of hard for them to express
what they want. So we'll sit down and talk and draw and back and
forth, and finally come up with a part."
Engels knew what he wanted, from his earlier work with BEC
machines. He ordered about 300 parts from outside sources—standard
items such as screws, bolts, lenses, and lasers, which were cheaper
to buy than to make, and which were, well, standard. Engels holds
up a small clamp. “It’s kind of a waste of their time to make
something like this,” he says. “They should be doing custom
work.”
There was plenty of that. Engels and the shop staff designed
more than 200 parts for the machine. They used an Auto-CAD, or
computer-aided design, program that shows exactly how a CNC will
shape a raw piece of stock into the desired form. It spells out
which tools will be used, in which order. And if something about
the design isn’t workable—if a material isn’t strong enough, or
cuts are too deep, or holes are set too close together—the virtual
piece will break. The designers will know, without wasting time on
the shop floor, that they need to adjust the plan. As Henry says,
“If it doesn’t work here, it’s probably not going to work out
there.”
Some shop members are especially good at certain things; Henry’s
great at finding and sealing leaks in vacuum chambers, and he calls
Rutherford “a master welder. He’s fantastic. All of us can weld,
but not like that.” Still, the shop does not work like an assembly
line, with each person doing only a few kinds of tasks.
“People in here are craftsmen,” says Rutherford. “We’ve got to
be able to do it all. Typically in industry, the machinist wouldn’t
be doing the program. He’d be setting up the machine, he might . .
. put the part in, change the part, and put the tools in; but he’s
not drawing or developing the method, the program.”
Do the craftsmen miss the good old days? What about the
satisfaction of making things entirely by hand?
“Well, yeah, working with the hands is the satisfying part—up to
a point,” says Rutherford. “After you’ve been in the trade for 30
years or so. . . It’s OK to make parts every day, but it’s OK to
let the machine do it too, you know?”
That’s especially true of “multiples”—more than one of a given
part. Making multiples with a CNC is more accurate than making them
by hand, and a lot quicker.
Henry picks up a white block about the size of a paperback book.
It looks like plastic, but it’s solid nylon. It’s been milled and
drilled in a precise pattern. A few dozen more just like it are in
a pile waiting to be picked up by someone in shock physics.
“To make each one of these by hand, you’d be there forever,” he
says.
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 A velocity block made for the Institute for Shock Physics, the Instrument Shop's single largest customer.
 John Rutherford at work.
As Engels’s story shows, experimental physics requires clever
hands as well as a sharp mind.
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