Critical to Gravity Probe B were four gyroscopes consisting of spinning spheres of solid fused quartz encased within a quartz housing. The four ping-pong sized rotors required exacting standards of homogeneity (inherent uniformity with minute density variations) as well as mechanical and electrical sphericity. Mechanically, the niobium-coated rotors were within 40 atomic layers (0.3 millionth of an inch) of a perfect sphere. These requirements called for both new manufacturing and measurement techniques. On orbit, spin-up of the rotors was accomplished by pumping a stream of helium gas past them in an intricately machined channel at nearly the speed of sound. Once spinning, the gas was pumped out of the housing creating a vacuum with a pressure lower than the space surrounding the orbiting spacecraft.
Roll Alignment

Exclusive gyroscope technology sets ParAlign apart

gyroscopes
Image credit: Stanford University/Barron Storey

ParAlign is a featured component of Prüftechnik’s Peak Roll and Geometrical Alignment (Peak RGA) service, and a big reason is its exclusive military-grade gyroscope technology.

This same technology has been used in aerospace navigation systems, including NASA’s space shuttle program.

The ring laser gyroscopes used in ParAlign are highly restricted because they are among the world’s most accurate—and they can be used for sensitive applications. The roll alignment measurement system is exact to a resolution of 4 μm/m (0.05 mils/ft).

This accuracy is possible through the use of three ring laser gyroscopes. With them, the ParAlign can identify its relative position in space at any time, creating precise and consistent results.

Among its peers in roll alignment, ParAlign is truly one of a kind. Only 38 such roll alignment systems exist worldwide. Its competitors do not utilize ring laser gyroscopes because of the restrictions around their use. Obtaining the proper permissions and clearances to use them takes years.

Pruftechnik founder Dieter Busch and his colleagues obtained government and other permissions necessary to purchase and use ring laser gyroscopes years ago. They performed extensive testing to determine if the gyroscopes would be accurate enough to measure roll alignment. They found ring laser gyroscopes to be the game-changing technology they had envisioned.

The benefits of ParAlign technology

Perfectly parallel rolls lead to improved product quality and productivity. Using the ParAlign gyroscope technology along with laser trackers—this is the combo that makes up Peak RGA—enables users to accomplish more alignment work in a shorter amount of time. Users get the most uptime for every minute of downtime spent.

As a laser roll alignment system, the ParAlign works faster and achieves more precise results than other methods. One significant advantage is that ParAlign systems do not require line of sight to perform measurements, unlike optical measurement systems. The other devices must often move and reset to capture that line of sight, which results in potential errors and inaccuracies. The ParAlign can also work in some enclosed or hard-to-reach areas where other types of devices cannot.

The precise and specialized technology of ParAlign helps companies quickly assure their rolls’ parallelism. With its speed, the ParAlign can measure 100 to 200 rolls per day. It can do in one weekend what a different device would take multiple weekends to accomplish.

After a quick setup procedure, ParAlign can measure entire machines during short maintenance outages. The results display instantly, allowing quick corrections and immediate re-measuring of adjusted rolls.

How ParAlign gyroscopes work 

ParAlign’s three ring laser gyroscopes work together to measure the parallelism of rolls in production facilities.

The ParAlign’s gyroscopes are arranged along three dimensions in space (X, Y, and Z). To perform a measurement, the gyroscopes shoot laser beams in opposite directions. One laser beam will hit the detector before the other as the sensor moves. The ParAlign is sensitive enough to measure that difference.

Paper, print, converting, and sheet metals are all industries with vast numbers of roll machines that rely heavily on maintaining roll alignment. These industries are well-represented in the Peak RGA customer base, but the service can benefit other industries as well.

Want to learn more about ParAlign’s exclusive technology? Read this product overview.

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