Creative Optics Shop Takes Aim At Tough Problems

Every day, in very different Southern California shops, there are problems posed by very complex projects challenging America's outstanding metalworking teams.

One such shop is the optics shop, Panavision Inc., a small unit that makes lenses for the world's finest motion picture cameras.

Faced with constantly evolving specifications, this production team is a very accomplished problem-solver. In recent months, they have demonstrated how much can be achieved when a creative shop team has access to tools with the right combination of versatility and accuracy.

Panavision cameras and lenses are used by the film industry to produce its finest products: the 35mm feature movies shown in theaters the world over. Considered by cinematographers to be the industry standard, Panavision's cameras and lenses are used to shoot the vast majority of the world's major motion pictures.

Unlike an amateur shooting a home video, the professional camera operator must have precise control over every shot.

In order to change focal length before or during a shot, a large and heavy cluster of lens elements is moved back and forth inside the lens barrel. These lens elements are held and guided by bearings seated in channels cut into the aluminum alloy barrel. To ensure precision, these channels must be machined within tolerance of 0.0002" not an easy task when the work surfaces are deep inside a thin-walled, four-inch diameter cylinder. Any misalignment of the bearing channels will cause distorted movement of the lens cluster giving the camera operator a false focal length reading.

"Until recently we used the broaching method to cut the channels," says manufacturing supervisor Nick Korda. "That was a very time-consuming operation. But if we tried to speed things up, heat would distort the barrel. And even at slow speeds, we weren't completely satisfied with the amount of variation we were getting."

Clearly, an approach was needed that could reduce the time involved and produce more consistent results. "Standard heads have the stability and accuracy we need," says Mr. Korda. "But there was a fundamental problem: they couldn't reach the work. On the other hand, we'd always been suspicious of angled heads. We're very concerned about consistency."

But there was a total solution: Tecnara MST modular RAA head.

As rigid as a solid head, the Tecnara MST head also provided a level of accuracy that would enable Panavision to produce lens barrels that consistently meet the product's demanding specifications. Equally important, the Rite-Angle's exceptional adaptability allows easy access to the lens barrel interiors.

Although the old broaching method was producing a very high quality product, Mr. Korda was not content to live with an expensive, time-consuming procedure that produced occasionally unsatisfactory results. "The Rite-Angle head helps us consistently achieve the kind of accuracy we need," he says. "Plus, the procedure takes about one-third as long as broaching. We're very pleased; the new method is an unqualified success in every respect."

This isn't the first time Panavision has solved difficult metalworking problems with unusual approaches, and it won't be the last. Although this facility differs greatly in size and purpose from many other shops, it is successful because it possesses two essential ingredients: a team of experienced, imaginative people and utilization of Tecnara's wide variety of high-quality tools that can be adapted to a range of tasks.

"We at Tecnara are proud to have a key role in these advanced operations," says Jordan Tetzlaff, sales engineer for Tecnara NC Tooling Systems (Santa Fe Springs, California), the supplier of Tecnara MST Rite-Angle heads and other precision tools to Panavision, Inc. ". . . any part we can play is very gratifying." MMS