New forming and patching methods have been developed for high-quality graphite/epoxy laminates. Laminates range in thickness from 0.012 to 0.018 in. (0.31 to 0.46 mm)

Burke, B.

Lager, J. R.

English

NASA Technical Reports Server

August 1975
	 B75-10164 
NASA TECH BRIEF 
S	 Marshall Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code 1<1, Washington, D.C. 20546. 
Fabrication and Repair of Graphite/Epoxy Laminates 
.
New fabrication and repair methods have been 
developed for graphite/epoxy laminates. The lami-
nates are of high quality and range in thickness from 
0.012 to 0.018 in. (0.31 to 0.46 mm). 
In the fabrication process, five separate laminate 
layers are used. The layers are mounted one on top of 
another in crisscrossing patterns with the fibers 
running alternately at +45°, -45°, 0°, -45°, +450. Each 
layer is 0.0015 in. (0.038 mm) thick. The layup tool 
used in this process is made from aluminum because 
of its high coefficient of thermal expansion. This 
characteristic is utilized to stretch the laminate when 
the assembly is heated. The result is improved fiber 
alinement. 
During the fabrication process, the mounted 
laminate structure is covered with a vacuum bag and 
is cured in an autoclave at a temperature of 180° F 
(83° C) at atmospheric pressure. After 10 minutes, the 
laminate is removed and smoothed with Teflon 
paddles. The process is repeated three times for a 
total of 30 minutes. After smoothing, the part is 
subjected to the standard cure cycle under an 
autoclave pressure of 100 psi (6.9 X 105 N/rn 2) and a 
temperature of 360° F (184° Q. 
These laminate structures can be repaired using a 
four-layer, precured graphite/epoxy patch with the 
layer fibers crisscrossed at +45°, -45°, -45°, and +45°.
The damaged area is cleaned to remove all the loose 
graphite/epoxy fragments by buffing the surface. The 
bottom side of the patch is roughened and cleaned to 
provide a good bond surface. Next, room-
temperature-curing epoxy adhesive is spread over the 
damaged region, and the patch is put in place. The 
repair is cured under 10 psi (6.9x10 4
 N/m 2) for 
approximately 16 hours. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Marshall Space Flight Center 
Code ATO! 
Marshall Space Flight Center, Alabama 35812 
Reference: B75-10164 
Patent status: 
Inquiries concerning rights for the commercial use 
of this invention should be addressed to: 
Patent Counsel 
Marshall Space Flight Center 
Code CCOI 
Marshall Space Flight Center, Alabama 35812 
Source: J. R. Lager and B. Burke of

Martin Marietta Corp.

(MFS-23228 and MFS-23229) 
Categories: 08 (Fabrication Technology) 
04 (Materials) 
06 (Mechanics) 
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.
https://ntrs.nasa.gov/search.jsp?R=19750000164 2020-03-19T20:25:46+00:00Z


Fabrication and repair of graphite/epoxy laminates

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