In a message dated 7/21/99 1:23:24 AM Central Daylight Time,
[log in to unmask] writes:
<< "My's" are Mydata's ; be it 19'[model No.](some 270 feeders) or 9's (much
less) ;
in my view most versatile mid range p&p on the market ,
Steve thinks it's Zevatech ; so I asked what am I missing on :
Always willing to be enlightened . >>
Hiya Paul!
Well, had my first day here yesterday and starting to get settled in...still
living outta cardboard boxes though, probably will be doing that for at least
a week anyway...hehehe.
Anyways, 'bout why I like Zevatech machines. I think Norm alluded to it
before. I used to work for Zevatech and maybe it's because I'm familiar with
them...Mydata's are a new beast to me...and like any animal, I like the
security of a known entity.
Yesterday being my first day, we were trying to run a first article on a
board they were just bringing up, and my first impression was that the
programming (especially the part data) seemed to be overly complicated
compared to what's needed when programming a Zevatech machine. This board had
a periphery cavity-down BGA (their first BGA placement) and they were having
difficulty getting the pattern correct for the machine to accept it...it was
finally programmed, but only after a bit of trouble.
Zevatech machines are so simple to program...in fact, just as long as you
have something in each of the feilds for the part dimensions (they don't have
to be correct) you can get the machine to look at the part and fill in the
correct dimensions by doing what's called a measure done by just pressing an
"Function, or F" key on the keyboard. The machine will go pick a part and
either measure it with the centering laser if it's not a vision placed part
(like caps, resistors, 50-mil IC's, etc.) or take it over to the camera if
it's a vision placed part and look at it, count the leads, measure them, look
at the body dimensions, etc. and automatically fill in all the data with the
correct data. 'Course when you do a auto-measure you must be sure the part is
good with no tweeked leads and whatnot...but what a peice o' cake! Can't tell
you how much time I've spent playing with part dimensions on other equipment
trying to get the machine to place the damn part! FUJI in my experience was
the worst...maybe things are a little easier now, I don't know.
Another thing I like about the Zevatech equipment is how flexible it is. You
can move the machines so easy, just crank the feet up and set it down on the
built-in casters, roll it to where ever you want, screw the feet back down
and level the machine, plug a air-hose in, plug the machine power in, and
you're off and running. When I worked for Zevatech doing an install at a
customer, I could uncrate a machine and have it up and running in as little
as 2-hours...most of the work was just getting it out of the crate.
One last thing about Zevatech that many other companies don't do, is if you
buy a machine they'll guarantee you a very generous trade-in amount on your
machine should you want to upgrade to a newer machine in the future...not
many other vendors will do that. Once you buy the machine it's yours, plain
and simple.
But, I guess I'll need to learn more about the Mydata machine before I can
truely critique it...it looks like we're gonna be keeping it here a little
longer than what was anticipated when I first interviewed here a month ago
from what I understand now. The machine here is supposedly fairly
young...only has around 4,000 hours on it. Don't look beat-up bad at all. But
I did hear from the maintenance guy that it's been going through what he
calls "MOT" cards quite a bit... maybe one a month lately from what he says.
Told me that they cost about $3,000...and Mydata doesn't repair or refurbish
them, you have to buy a brand new one ever single time something goes wrong
on one of the cards. I'm not sure, but I think those are motor control
cards...gotta get into the manual. Yesterday there were a couple of times the
machine had a few weird problems that they needed to shut it down and restart
it (not sure exactly what it was, I was mostly a "newbie" observer) But they
took a couple of covers off of the top of the machine and was looking around
there, and I noticed that there was a long blue ribbon cable that had a lot
of little "kinks" along the edges, I looked down along the rollers that guide
them while the head is moving and didn't see anything that I thought was out
of place. But the other engineer told me that ribbon cable was just replaced
a year ago.
Anyways, I'll learn more about it and may even get to like it as much as the
Zevatechs...even though from what I saw yesterday, the Mydata isn't nearly as
quick as the Zevatechs by a long shot.
Gotta quick question that I think I know the answer to, I just wanna bounce
it off you guys. When tenting the vias beneath a BGA package, you want to
tent on the bottom of the board if you're gonna wave it, right? But if the
board is tented from the topside, and during the "Tape test" for soldermask
adhesion a just couple of the mask plugs from the vias come off, is it a big
deal? I know ideally you don't want any coming off, but is that a problem
where you wouldn't build the boards?
Thanks ya'll!
-Steve Gregory-
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