Hi Tim, 8-mil huh? Boy, that's getting down there...you know, placing 8-mil is one thing, but printing solder paste on 8-mil pitch is another. Most of the time when I've seen 8-mil pitch on a board it's been attached with hot-bar...but I guess you COULD print paste and place components if you really wanted to do it that way. Matthew is right about big bucks. The machine vendors that will state, AND back their statements about their machines being able to place 8-mil is going to cost some money...from my experience though, the finest pitch that most guarantee is 12-mil. That doesn't necessarily mean that a machine won't place below that, it's just that they won't guarantee it. When you get down to that fine of a pitch, things like the ambient temperature that the machine is operating in can affect placement accuracy. If you guys are looking at Amistar, then that tells me that you're looking at something midrange. I've got some experience with Amistar machines, I worked at Smart Modular Technologies who has 13-lines of Amistar machines. They're good memory module machines, and they even surprized me with how well they did with some 128-pin 15.7-mil TQFP's that went on a PCMCIA MPEG card that we built while I was working there. But 8-mil, no-way. In that price range, I might take a look at Zevatech's FM760. They won't guarantee 8-mil, I know that, but they will guarantee 12-mil...and on a good day I think the 760 could do 8 mil. The thing in my opinion that the 760 has over a lot of other machines, is the closed-loop linear encoders they use to position the placement head. The 760 has Sony magna-scales in both the X and Y axis to feedback to the machine's CPU when it's reached it's placement point, instead of relying on rotary encoders like many machines do. There's been some flip chip with 3-mil bumps on a 6-mil grid placed with the 760 that I know of, but that was on one of those "good days"... Good Luck! -Steve Gregory-
reply »