A big Diff pump

[johnf]

I was up the other end of the country today helping out at a PVD facility

heres a pic of the 100,000litre /sec diff pump not quite as high as me but considerably fatter
fluid charge = 4.1 litres of santovac heater 8kW
immediately below my arm is the roots blower that aids the monsterous two stage backing pump

the large lines around the Diff pump are the roughing/ backing lines and valves

[Doug Coulter]

Wow, that's a lotta Santovac -- a real good chunk of change to fill that guy (I'd guess they get a good discount over Lesker's pricing). We are seeing a lot of diff pumps in that size range around here, going cheap as surplus, but what in heck would one do with one as a "home lab"? So far, I've not been able to get interested in buying any, though they are going for about the price of the scrap metal, I've just not figured out a use for one. I'm even having trouble figureing out what they were used for locally. We don't have any big semiconductor fab, no CD's are made here that I know of, no big deposition outfits I'm aware of. We do have some steel business, so maybe someone was doing heats under vacuum.

I've seen some of that other stuff, huge roughing pumps, used in HVAC gear for a large church up in the DC area I happened to be at. Another tech-head heard the thing running and dragged me over there to look at it, and yep, big roots pumps -- he'd recognized the sound.

[Joe Jarski]

Doug, one of those diff pumps might work for removing the air from the lab so you don't have as much scattering going on.

[Doug Coulter]

Ok, out comes the caulking gun!

[johnf]

Ok guys the pic was taken on a blackberry
note the sputter ion sources over to the right of the pic (3 visible 16 total around chamber) each 8kW when running using Ti cathodes, process gasses 4 main ones N2 and acetylene with argon and Co2 standard conditions when running 2000 sccm gas flow 2 e-6 millibar in chamber 2microns /hr approx TiN or TiNC.
chamber around 6 feet diameter around 8 feet tall

[Doug Coulter]

Makes me wonder if any of my tools were in that chamber once. I've almost given up using TiN -- bonds well to all too many things I try to cut. But TiCN, that's the stuff when plain old high speed steel doesn't get it and carbide leaves too rough a finish.

I got a cool batch of defective "TiN" drills. Look like Christmas ornaments, all the reds, greens, blues, no yellow. I wondered about that (cheapo Chinese from northern hydraulics on a deep sale), but they are good cobalt steel underneath anyway, and for $30 per 115 bit set, not so bad. Only after I started using Ti grids and doing some sputtering pumpdowns in air/argon did I understand what they'd done wrong -- I have a tank that looks like that inside now (BillF's fusor). I'd heard (but never tried) they used ammonia for TiN, but then...hearsay.