Electronics Forum | Sat Jun 22 21:06:27 EDT 2002 | jersbo
I agree with PJC.. The mention of 2 QFPs to wave = more than likely rework to remove bridges and a potential to scrap the board, 25mil isnt as bad as 20 or less.. but the potential is still very real.$$$$$$ reflow/reflow is my 2 cents with the possib
Electronics Forum | Thu Jun 20 04:41:47 EDT 2002 | redmary
thanks, but I also encounter the solderability problem. because these boards are HASL or Ni/Au finish, and we print the solder paste and reflow, the result shows the some non-wetting area. and the reliability test also proves to be bad. so the critic
Electronics Forum | Thu Jun 20 14:39:35 EDT 2002 | russ
I use TechSpray Wsol 2204-8SQ. This is a water soluble mask that is very thick and works pretty well for this application. Drying time depends on thickness and you should let it dry at least for a little while prior to running through the wave. Ea
Electronics Forum | Sun Jun 23 23:23:25 EDT 2002 | beldorian
First question - I am making an assumption that after "de-pop'ing" a BGA prior to socketing the thing to test it, the best known practice is to re-ball the thing. Is this an industry standard? Second question - If it is an industry standard, does a
Electronics Forum | Wed Jun 26 15:34:09 EDT 2002 | Daan Terstegge
It does work, but you must keep in mind that not only the stencil must be designed for it, but also the board. Trying to use the pin-in-paste process for a connector with an ordinary wave-solder layout will result in lots of touch-up. You'll need sma
Electronics Forum | Mon Jun 24 19:15:13 EDT 2002 | Chris C
Do I really need a Vapour Phase Oven or a Nitrogen Oven when soldering PBGA's if my PCB has only 2 to 3 BGA's (ball pitch of 0.5mm to 1.27mm) ? Is the quality of soldering when using an 8-Zone Convective Oven is not acceptable? I have been bombarded
Electronics Forum | Mon Jun 24 21:56:15 EDT 2002 | davef
Russ is correct. The sales-types telling you these stories are not acting reputably. You should not allow them in your plant. If you do not control the sales-types that gain entry to your plant, ask that person to come on-line here and we will exp
Electronics Forum | Wed Jun 26 08:53:32 EDT 2002 | davef
We have not done a DOE on board warping. Consider: * How close the board gets to its Tg during the reflow cycle * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * Time at temperature
Electronics Forum | Wed Jun 26 21:05:15 EDT 2002 | ianchan
Hi Dave F, customer calls it "warp", we can call it "twist/bow"..etc. the "warp" occurs on individual PCB cells of 28per each panel. the overall dimension of the panel is 139mm x 168mm, and each individual PCB cell is 2.4mm x 1.2mm. Thickness is 0.
Electronics Forum | Thu Jun 27 17:24:17 EDT 2002 | Daan Terstegge
Never did a DOE on that, but I think it would be quite difficult to warp a board inside the oven if it was flat when it entered the machine. If there's no center-board support then it's another story, then the board will bend due to it's own weight.
