Vacuum assisted welding chambers?

[pekan]

I need a way to weld various titanium parts. Does anyone have experience in the use of a Vacuum assisted welding chamber? Or another cost efective method that doesn't involve building a fixture for each part?
This is not my area of expertice so any info at all would be appreciated.

 

[jeffita]

Vacuum chambers are very expensive.
In 1992 Mcdonnell Douglas paid $250,000 for one.
Of course it was large, 4'x4' x8' long with a
24" loading tube that was 15' long.
We welded all sorts of ti parts in these, with the
longest being wing deicing ducting, for the DC9/MD 80
now 717 series. and of course military assemblies.(f-15 wing spars)and other "trick" stuff.

these chambers would pull down to 3 microns and had to
hold a vacuum for a certain length of time to be certified for the then mil spec 1595-a. along with us weldors our
equiptment had to be certified also.

After pulling down to 3 microns you shut the pumps (2)
down and back fill with argon untill it reaches room pressure, then you run a bead on a test coupon, if the coupon is silver to light yellow you start working, if not
i.e. the weld is bright yellow or bluish you pump down again.

I know this is long winded but i thought you might want to know what is involved and how expensive it can be.

I think maybe a purge bubble would be more cost effective.

A purge bubble is a plexiglass enclosure where argon can either flow through or you can use a low vacuum pump to
"dry out " the chamber before you fill with argon.

Then there is the "box" which is just that, a box you fill
with argon and you put the part and your hands down inside of it and weld away, of course this only works for small parts.

There are other tricks to welding outside a chamber but it involves special hand made cups and other tooling that is not what your looking for.

Hope this helps.

Jeff