Post by PoouaPost by Samuel M. GoldwasserOn Thursday, September 8, 2016 at 3:17:36 PM UTC-5, Samuel
Post by Samuel M. GoldwasserPost by PoouaA long time ago, I spent a few months working for IMO Varo, a
government sub-contractor. I was a Laser Tech II, assembling eye-safe
laser rangefinders for use on the battlefield. Varo doesn't exist
anymore, but it made a lot of lasers. I'd like to find some
documentation on them, just to have the information. That's one of the
last things I said that I'd try to find years ago, when I last posted
on this forum. I came close, once, when I spoke with one of the last
employees for Varo.
http://repairfaq.cis.upenn.edu/Misc/laserscl.htm#sclvaro
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sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Thanks, Sam. That is the device that I was building for IMO Varo in
1994/95. I hardly ever saw it in finished form, though. My job was
assembling the laser cavity, consisting of the two gold-plated
reflectors, a flashlamp, laser rod, o-rings, and mounting brackets on
a test base. This was done at the start of the assembly line, and I
turned over my completed units for testing before they went on to
mounting to the electronics boards.
We had two types of o-rings; nylon and rubber, I think, one for the
flashlamp and one for the laser rod. We had to be careful not to touch
the end of the laser rod with the o-rings, as they would contaminate
the rod. We used a three-solvent process for cleaning the ends of the
rods. I don't remember the solvents we used, but two of them were
hydrocarbon (methanol, ethanol or butanol, or something like that) and
another alcohol, and we lightly dragged a moistened lens cleaning
tissue across the end of the laser to clean it, then inspect the
result under a magnifying glass. We also checked for the chamfer on
the end of the rod, to ensure it was in tolerance.
Sometimes, the gold plating on the reflectors was not uniform and kept
the tab on the two halves from fitting inside the groove in the end
brackets, so we had to file them down a little bit. As long as we
didn't file down to the underlying nickel metal, we could use the
reflector. Somewhere, I might still have a bag of tissues that I used
to wipe up the gold powder from the filings (though, not enough gold
in them to be visible).
The guys in electronics who assembled the flashlamps had trouble
brazing the electrodes to the flashlamps, which caused a lot of
problems. The electrodes often were so brittle that they would snap if
we bumped them. If that happened during our assembly, we had to
disassemble the whole thing and start over from the
beginning. Considering that we barely had enough time to turn out our
quota (ten a shift, minimum), I took to bending the wires before
beginning assembly. That is, until my supervisor asked me to
demonstrate what I was doing. I gave one flashlamp lead a good tug and
heard my supervisor suck in air fast. She told me to be not so
aggressive. I think that by that point, we were just trying to get
assembled units out the door, without really caring how long they held
together after that, though, from what I hear, none of our finished
product ever actually made it past environmental testing.
I learned, a decade later, that Varo had already agreed, even before
they hired me, to transfer all their laser clean room material assets
to another company as they went out of business. About four months
after Varo moved me from Albuquerque to Garland, they included me in
the first wave of layoffs of 200 people. That was the end of my laser
career. This was my first and last job as a laser technician. A decade
later, I returned to Garland just in time to video record a worker
demolishing the walls of the building that used to house our clean
room facilities. That area now is a Baylor Hospital parking lot.
Interesting. ;-) Sorry about your short laser career.
I would like to put an edited version of what you wrote in the Laser FAQ
at the end of the Varo section.
Cheers,
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sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
I'd be happy for you to do that. It seems good to me that someone
makes a record of the manufacturing processes we had. In fact, I'd
like to give a longer description of the facility, what I can remember
of it, 22 years after the fact. Feel free to use what you like.
Laser assembly took place in the Optical Systems Division building,
located on Walnut Street in Garland, on the other side of a small road
from a Long John Silvers. Google Maps shows it was near 2203 W Walnut
St, Garland, TX 75042. The LJS apparently is gone, and the entire
laser facility is just a grassy field and parking lot behind Baylor
Hospital. Even the little road is gone, though you can still see
vestiges of it if you know where to look. The laser facility was a
rectangular, concrete, single-story building. I was fascinated by the
parking lot lamps, which had large, clear glass spheres on top of
round, black poles; the way they were arranged on the property was
hypnotic to me. Behind the building were tall metal pipes painted
matte black. I remember that one of them had a large, circular hole
near the top. When I asked about them, I was told these were used for
testing laser beam propagation.
The building had one entrance on the short side facing Walnut Lane,
and a side entrance way down at the far end of the building on the
left side of the building. I usually entered through the entrance on
the left side of the building. It was a badged entry. After swiping my
badge on the sensor, I would enter and greet the secretary seated at a
small desk in the alcove. She might have had Parkinson's, as she
always shook, and she walked with difficulty using a walker.
I walked down a hallway and around a corner to another hallway. I
could see electronics assembly work stations through the half-glass
walls along the hall. Somewhere along the way, I put on a hairnet,
smock and booties. Then, I came to a sliding door through which I
passed into a vestibule. This was the airlock used to maintain our
Type 10 clean room. Laser assembly took place inside the clean
room. To the left was the assembly process for the Cr:Er:glass
eye-safe laser range finder; to the right was the assembly process for
a non-eye safe IR laser range finder used on missiles. I worked on the
left side.
As clean as the room was, we used flow hoods at each work station to
provide an even cleaner assembly environment. We did our work while
wearing finger cots, latex that fit over our fingers. We had to change
them every twenty or thirty minutes, as our skin oils and sweat would
otherwise penetrate the latex sufficiently to contaminate our work
surfaces. We worked ten to sixteen-hour shifts, with a half-hour lunch
break and short breaks during the day.
My understanding is that the Cr:Er:glass laser range finder was
supposed to function similar to a pair of binoculars. A user would
hold it up to his eye like a pair of binoculars, to sight a
target. Once sighted, the user could push a button to emit a laser
pulse that would reflect off the target, and the trip time measured by
the unit. I never actually saw this finished device in real life, but
I remember seeing photos of them.
After entering the clean room from the airlock, I faced the solid
metal backs of some work stations, reaching up nearly to my shoulders,
so I could see across the room. I walked to my left to the end of the
row of three work stations side-by-side, and then made a u-turn to my
right. My work station with flow hood was straight ahead of me, with
one work station to the left of mine. To the left of that work station
was a wall. In front of the wall was a stand that had plastic tubs
containing the raw parts that we assembled, flash lamps and little
square plastic boxes with flip-top lids and foam rubber inserts
holding the laser rods. Each flash lamp cost something like $50, and
each laser rod cost somewhere around $600 or $800. I don't remember
what the gold-plated reflectors cost.
We cleaned the ends of each laser rod prior to assembling into a laser
cavity. We had little plastic squirt bottles that held our solvents. I
think we also had distilled water. We had a specific sequence of
solvents we were to use, but I don’t remember what it was. Each lens
tissue could make only a single pass across a laser rod. So, we would
put the dry lens tissue on top of the rod end, apply a drop of
solvent, then drag the tissue across the rod end, and then throw the
tissue away. We did that for each of the three solvents, and then
examined the rod under magnification for cleanliness.
We also examined the ends of each rod under magnification to check the
quality of the antireflective optic coating. The coating lab had
production problems, resulting in tiny bubbles or dust in the
coating. The bubbles shone like little stars. We had to reject the
rods if they had too many imperfections in the coatings. As I
mentioned, we also checked the chamfer of the ends. If we rejected a
rod, we put it back in the little box and put the box into a tub of
rejects. The coating lab was working on salvaging some of the rods,
though without much success. Actually, the results were horrible, and
I rejected every one of those refurbs that I saw.
I accidentally snapped a laser rod while assembling a laser cavity. It
was a stupid mistake; I adjusted the height of the rod while it was in
the gig, instead of disassembling the whole thing, and the rod snapped
under stress when it began bending over a piece of metal attached to
the gig. I quietly put the rod in a box and placed it in the reject
bin. I was relieved that no one ever said anything about it.
As a joke, one of my co-workers put a small pieces of paper folded up
into one of the boxes, with a note on it saying, “Help, I’m trapped
and forced to build lasers.”
I put the o-rings on the laser rod while under magnification, too. I
remember that the rubber o-rings were naturally filthy, at least from
our magnified, highly-clean perspective. Rubber has natural oils in
it, and has a flaky surface, either of which would contaminate the
ends of the laser rod and our finger cots. We had to change finger
cots after putting the rubber o-rings on the laser rod, and we had to
be careful not to touch the end of the rod with the rubber o-ring.
As I walked around the room, I might pass the man whose job was
measuring the room’s air quality. He had an instrument on a wheeled
stand that told him how many particles of dust were in the air. He
rolled this device around the entire clean room to make his tests.
On the left side of the room was a window for passing small items
between the lab on the other side of the wall with our lab. A little
farther down our room on that side was the optic alignment check
room. Across from that room was the station where the firing circuits
were added to the laser cavity. Somewhere along here, the laser cavity
was removed from the gig and placed on its permanent mount.
I don’t remember which stations came after the firing circuits, but
down at the far end of the room was the QC Department, which checked
all our work. One of my classmates from Albuquerque
Technical-Vocational Institute, where we both graduated with AAS
degrees in Laser Electro-Optic Technology, worked in the QC
Department. I never knew why management chose to put him in QC and me
assembling laser cavities. I think we both were working on the
eye-safe laser range finder because it was considered easier to
assemble than the laser system for the missiles; experienced laser
techs went over to that side.
Environmental testing took place in a completely different room in a
different part of the building. I never saw it. Other rooms in the
building included a room with a sandblaster and a grinder. I remember
that someone helped me retrofit a broken hex wrench so I could do my
job; it was sometimes difficult to find the tools we needed to
assemble lasers.
I think it was before Christmas that I found that the electronics
assembly rooms were unmanned and the lights turned off. Management had
also brought in temp workers to help us assemble lasers, but then it
turned out that the laser techs (who had laser degrees and were
full-time employees with benefits) were being replaced by the temp
workers. One of the temp workers was so disgusted by what management
was doing to us that he quit in protest. Even so, we didn’t know when
our end was arriving. For me, it was January 13, I think, when I was
hunched over my workbench, getting everything set up to begin work,
when my supervisor told me to follow him. We walked to the other side
of the room, the missile side, and he told one of the workers on that
side to join us. We were told to meet in a room on a certain day and
time. As I said, there were about 200 of us in there. I saw the woman
who walked with the walker in there with us, too.
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