Electronics Forum | Wed May 29 14:42:53 EDT 2002 | jaltland
I have another question about bga's and stencils. We were told by a manufacturer to use .012 square apertures for .009 dia balls. The original pick & place and reflow goes pretty well (over 95% good), however when we have to select components on th
Electronics Forum | Wed May 29 12:41:46 EDT 2002 | peterson
I'm out here on the leftcoast. Actually, our method for removal is: break down the sides, pull each pin individually. It's tedious and time consuming, but it can be accomplished with little risk of damaging the board. Customers are curious, however.
Electronics Forum | Wed May 29 19:00:08 EDT 2002 | russ
Have been seeing a pretty fair amount ourselfs. it seems to come and go. Couple of questions 1. Are the parts shifting to one side during reflow? 2. is it true non wetting to the component? I have been experimenting with different pad geometries a
Electronics Forum | Tue Jun 04 17:21:22 EDT 2002 | jasonfang
I found solderballs are around chip components (on one side of middle area), I checked gerber data, solder paste of aperture on the stencil for these chip components have 5% reduction to solder land on PCB, shape of solder land are square, not home p
Electronics Forum | Thu Jun 06 15:55:28 EDT 2002 | arzu
I agree with the others and experienced the problem myself this week. Solderballs at the side of the chips. I looked at the board and found that the chip is pressing the paste away too much. This in combination with our quite big pads(and stencilaper
Electronics Forum | Tue Jun 04 17:05:52 EDT 2002 | davef
Solder balls floating around on the air currents of a reflow oven. I sincerely doubt it. Could the solder on your gold fingers be from: * Excess placement force during P&P? * Ejactula from solder deposits during rapid preheat ramp rates? * Ejactula
Electronics Forum | Tue Jun 18 17:01:50 EDT 2002 | kenbliss
Todd, for the sake of the forum could you please spell out a few key line items about why you state the Juki machines is Junki. Clearly you are unhappy with their machine. The best purpose of this forum is to identify problems with machines, proces
Electronics Forum | Fri Jun 21 12:59:20 EDT 2002 | stepheno
When you say well designed for wave, does that include "extra" solder pads for the IC's for solder thieving? And Boards that are well designed for wave don't have QFP's on the bottom. They might be ok but then the board would be "ok for wave", but no
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 | 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
