Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Wetting problem of PCB after reflow soldering

park kyung sam

#17593

Wetting problem of PCB after reflow soldering | 14 September, 2001

Hi.

After reflow soldering. There are lots of non wetting of leads. 71 b'd all are mounted resister,condensor,qfp,plcc,bga have got the defects so many. all defecs occured in the fine pitch ic. others are good. On some fine pitch pads not mount with component. there is a solder ball not wetting on pad. i confirm that the b'd is bad for wetting. this b'd got hal process not gold. i have never seen just like this much. is there some body who has got &can give me the report analyzing this defects. My e-mail address is gsparka@lge.com. thanks in advance

reply »

#17602

Wetting problem of PCB after reflow soldering | 14 September, 2001

How in earthly heaven would someone else have a report analyzing the defects on your boards? Among the good failure analysis labs that can assess situations like yours are: * Robisan Laboratory 6502 East 21 St Indianapolis, IN 46219 317-353-6249 fax 357-1270 Susan Mansilla, Technical Director Robisan1@aol.com * Trace Laboratories - East 5 North Park Dr Hunt Valley, MD 21030 410.584.9099 Fax 9117 tracelab@connext.net http://www.tracelabs.com

Other reputable failure analysis labs are listed at http://www.ipc.org

Thinking about your situation, where the fine pitch parts do not soldering well, when other components do solder well � tell us: * Initially, it would seem there is a problem with the fine pitch parts, but you stated that fine pitch pads without components soldered poorly [and it�s probable that all of the fine pitch parts are not from the same supplier]. So, do the fine pitch components that did not solder well on the board have acceptable solderability? * That, generally, the boards solder well, except the fine pitch parts, raises the issue of a substance is between the copper on the pads and the HAL. Is the substance copper corrosion, solder mask bleed, board fab processing materials that were not removed, or what? On a board with poorly soldered fine pitch parts, can you solder a pad with an iron and a fairly active flux [not that fine NC stuff]? If not, will it take solder, after scraping the pad with a xacto knife blade? What kind of solder mask is on the board? * What is your board supplier doing to help you understand this issue? * How do you process and what materials do you use on these boards? * With regard to the problem, what is the history of processing this board? What is the extent of the problem, across product lines?

reply »

mugen

#17605

Wetting problem of PCB after reflow soldering | 17 September, 2001

Hi,

(me been absent for some time...)

Are your brds confirmed HAL over copper? (check out what Dave F mentioned abt possible root causes) or are the brds HAL over nickle? (shd be no problem here, if so?) or are the brds strictly nickle plated pads? (thats a bad thing, as eutectic solder don't like nickle pads, so get em nickle covered with second lay of HAL solder, and the wetting shd be resolved pretty enuff...)

Good Luck!

reply »

reflow oven profiler

Reflow Oven