System using a pulsed ruby laser balances or trims gyro rotors spinning at speeds of up to 24,000 rpm. It is designed to detect high spots on the spinning rotor and to focus a precisely timed laser beam on these detected spots

Popick, H.

Roberts, D. L.

English

NASA Technical Reports Server

June 1968	 Brief 68-10225 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia. 22151. 
Laser System Used for Dynamic Balancing of Gyros 
A system employing a pulsed ruby laser has been 
developed for dynamic balancing or trimming of gyro 
rotors spinning at speeds of up to 24,000 rpm. The 
laser system is designed to detect high spots on the 
spinning rotor and to focus a precisely timed laser 
beam on the detected high spots. The system con-
forms to the following specifications: 
Rotor speed range:	 2,000 to 24,000 rpm 
Rotor diameter:	 Up to 5 cm 
Pulse width:	 Mode 1: 500 micro-
seconds 
Mode 2: 40 micro-
seconds 
Pulse energy:	 Model: 25 joules 
Mode 2: lOjoules 
Focused spot size: 	 1 mm 
Pulse synchronization: Panel meter enables 
operator to set laser 
beam at any point on 
the rotor. 
Typical metal removal	 Mode I: 0 to 2.0 milli-
per pulse:	 grams 
Mode 2: 0 to 0.5 milli-
gram 
In tests on rotors made of a number of different 
metals, photographs were taken of the plumes result-
ing from the metal vapor produced by the laser beam. 
These photographs showed that normal incidence of 
the laser beam on the workpiece results in the greatest 
amount of back splatter. Angles of incidence ap-
proaching tangency to the workpiece produce the
least amount of back splatter. For any particular 
metal, an optimum angle of incidence must be de-
termined experimentally. 
This laser system could be used to dynamically 
balance most types of small, rotating high-speed 
components, including air turbines. The system offers 
the primary advantage that the component to be 
balanced does not have to be removed from its bear-
ings. With conventional balancing methods, which 
require drilling or grinding of the component, the 
component must sometimes be removed from its bear-
ings. These methods are more time-consuming and 
less accurate than the laser beam method and may 
result in damage to the bearings. 
Note: 
Details may be obtained from: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B68-10225 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: H. Popick and D. L. Roberts

of Korad Corporation
under contract to

Marshall Space Flight Center 
(MFS-12218) 
Category 05 
This document was prepared under the sponsorship of the National	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately owned rights.
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Laser system used for dynamic balancing of gyros

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