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Non-Vacuum Electron Beam Welding with the Plasma Arc Window
At this point, we feel that the plasma window technology has reached a level of maturity, where the next natural step is to convert one of our main production high-power welders (25 kW) to non-vacuum operation. Once this has been completed and its results are repeatable, we will begin to weld with this new technology on a production basis. We expect this to happen within this year.
Perhaps the most exciting new development from this program to date is the possibility of Plasma projection. This new invention is currently being written and the patent application will soon be submitted. This new technology will allow for "Plasma Shielding for In-Air and Under-Water Beam Processes."
#1 Vacuum Differential Pumping Efficient Vacuum Differential Pumping equates to less energy consumption, resulting in large cost savings in the operation of the electron beam non-vacuum welding process. One of the major goals is to achieve a satisfactory separation and preservation of the high vacuum area where the electron beam itself is generated, while enabling its transmission to atmosphere. To date, results have confirmed that we have attained excellent electron beam transmission. The accomplishment of this endeavor in itself has shown results that have significantly more advanced vacuum separation than conventional non-vacuum EB welds. The improved vacuum stages that are necessary for vacuum separation are attributed to one of the functions that the Plasma Arc Window offers. Most of today's non-vacuum machines typically require a total pumping capacity of approximately 3200 CFM to attain necessary separation. The Plasma Arc Window is providing far better energy consumption results with only 42 CFM, or 91.5% less energy consumption. Advantages and cost savings over conventional non-vacuum electron beam welding machines are:
Note: Other technical advantages have been omitted until the results have been measured. The major goals of this development are to:
To date we are talking to four separate companies that have interest in this new technology. There are two companies in Germany, one in Spain and one in the United Kingdom. Two of the four companies have requested and received quotes for one of these units. Technical articles authored and co-authored by Brookhaven National Labratory scientist Ady Hershcovitch
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On
April 29, 2004 Acceleron LLC demonstrated to the DOE and NU non-vacuum
electron
beam welding with an electron beam that was transmitted
from machine vacuum to atmosphere through the plasma window. The
attendees were able to witness that Acceleron has successfully
accomplished electron beam welding with this new technology. During
the demonstration we welded 3 consecutive samples that showed repeatable
results. The non-vacuum welding was performed with a low-power electron
beam welder (6 kW), which in itself is quite remarkable.
During
our discussions after the weld demonstration, we shared with all
the attendees some of the additional advantages and further
success this new technology can bring along with other testing
that needs to be done in order to better sell this technology to
the market place. The first encouraging news we have is that the
initial weld results are much better than what Ady Hershcovitch
anticipated. The welds are more narrow and deeper with the amount
of power used
to produce these welds. "After just 2 weeks of weld development
the welds are truly of text book geometry," he reported. To date
each time we have made a design change to the Arc itself, or to
the differential
pumping section, we continue to witness further improvements to
the weld and its geometry. This is not to say that all changes
will have a positive result, but it does show that we are on the
right track with optimizing the complete system for the best possible
results. As anticipated, we have been able to greatly reduce the
amount of energy required with our system set up and the use of
the Plasma
Arc Window verses the Non-Vacuum systems used today, see the details
below for more information.
Our
next goals include further development using the existing 7.5
kW EB machine to optimize differential pumping and Arc design.
While this is in progress our team will continue with their experiments
to continue with the Arc projection bench testing. In conjunction
with the Arc projection testing, we will also continue to improve
our system design and begin to build a third Plasma Arc with the
changes that have been learned. While the third Arc is being built,
we will begin to modify our high-power 25 kW machine to do more
accurate weld comparisons to the machines used in today's
industries. This next test is imperative so
that we can show side-by-side weld comparisons at the same power
levels and processing speeds. Once this has been completed, we
will then begin welding with this new technology on a production
basis. 
