Report describes 10-kW laser welding system, designed to weld large structures made from 1/4-inch and 1/2-inch aluminum (2219) and D6AC steel

Hella, R.

Locke, E.

Ream, S.

English

NASA Technical Reports Server

bctober 1975	 B75-10267 
NASA TECH BRIEF 
Marshall Space Flight Center 
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commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
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be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Industrial Laser Welding: An Evaluation 
A report has been issued documenting a 10-kW 
laser welding system. The laser system was designed 
to laser-weld large structures made from 1/4-inch and 
1/2-inch (0.88-cm and 1.77-cm) aluminum (2219) 
and D6AC steel of the same thicknesses. 
The study, based on 150 separate weld cycles, 
determined that good-quality welds could be achieved 
in both the 1/4-inch and 1/2-inch D6AC, but a 
limited amount of preheat was required. If no preheat 
was used, the welds usually cracked. The 1/4-inch 
aluminum was successfully welded only after a 
heavy-duty, water-cooled shielding hood was devel-
oped. While full penetration of 1/2-inch aluminum 
was easily achieved using this hood, excessive and 
erratic dropthrough prevented the generation of good 
welds. By milling the material down and increasing 
the welding speed, acceptable top and underbead 
geometries were produced. However, these welds 
showed excessive porosity near the weld root. Limited 
reductions in material thickness reduced porosity. 
The collimated laser beam is focused by a telescope 
positioned at the joint of the pieces to be welded. To 
aline the laser beam to the joint, the red beam from a 
He-Ne laser, coaxial with the high-power beam, is 
folded into the optical system. Gasses for both top and 
underbead shielding are controlled and metered from 
a gas manifold located just outside the work station. 
For all of the D6AC welds, a hood containing both 
a forward-facing gas jet (used to prevent ionization of 
the laser-generated metal vapor) and a trailing shield 
(to prevent oxidation of weld molten metal) was used.
For the successful aluminum welds, a hood that had 
evolved through several design states was used. 
The original hood was built from pressed 
stainless-steel mesh which served as a diffuser both 
along the bottom and around the chimney. After the 
first welds were made in the thinner aluminum with 
this hood, the mesh at the bottom of the chimney 
burned out. The mesh was replaced with a porous 
bronze plate bonded in place with epoxy resin. Other 
problems occurred with epoxy contamination and 
soft-solder diffusion. The final hood was made from 
heavier-walled material with a machined seat for 
mounting the diffuser. Water cooling the chimney 
added to its durability. 
Note: 
Requests for further information may be made in 
writing to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Code ATO1 
Marshall Space Flight Center, Alabama 35812 
Reference: TSP75-10267 
Patent status: 
NASA has decided not to apply for a patent. 
Source: R. Hella, E. Locke,
and S. Ream of

Avco Everett Research Laboratory 
(MFS-23237) 
Categories: 08 (Fabrication Technology) 
04 (Materials) 
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
	
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https://ntrs.nasa.gov/search.jsp?R=19750000267 2020-03-19T20:14:44+00:00Z


Industrial laser welding: An evaluation

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