Electronics Forum | Tue Apr 23 03:48:00 EDT 2002 | mitchell
The metioned process will work, but I do have 1 Question, How are the PTH comp. being inserted? If automated insertion is going to be used the process may have to change. Topside SMD - then Auto insert PTH, the reason for this, is depending on the 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 | Wed Jun 05 12:22:45 EDT 2002 | Bob
No. Placement force is fine. Also boards have been inspected prior to reflow using microscope with no evidance of misplaced solder balls. The ramp rate has been reduced to acceptable limits, typically .8 - 1.5 degrees per sec. Outgassing from eithe
Electronics Forum | Thu Jun 06 16:26:36 EDT 2002 | Bob
Thanks for all the input. It is pretty much what we have checked for, microscopic analisys before printing, assembly and reflow, but like we all seem to agree one ball of solder is hard to find. The boards are full QWERTY keypads with a few LED's a
Electronics Forum | Wed Jun 12 11:14:57 EDT 2002 | pjc
Sam, Like I said, AOI for pre-reflow inspections is the easiest to program and maintain. Each vendor of AOI has its pluses and minuses for programming and performance. Do a careful investigation of each vendor to learn about their machine performanc
Electronics Forum | Fri Jun 14 14:32:05 EDT 2002 | davef
There is no real reason why you shouldn�t use your current paste. Paste for printing usually is a coarser mesh than paste for dispensing. Dispensing paste is more expensive, because of the mesh and the packaging, but that doesn�t matter now. Compa
Electronics Forum | Sat Jun 15 22:49:23 EDT 2002 | edahi
well as usual this for flip chip however, this application uses ceramic substrates and the nearby area in which the splatter land on is the marking area (gold pad). We cannot hide this because the package is completed bare die, meaning no heatspread
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 | Wed Jul 10 04:53:47 EDT 2002 | redmary
a leakage exists in the capacitor net (1206), which cause the voltage down so much. the process flow is: printing-placement-reflow-hand load-wave-depanel-FT. I find possible stress maybe exists in the depanel stage, does the extra stress cause the ca
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