Electronics Forum | Sun Dec 09 22:54:20 EST 2001 | dburr
It sound you have already discovered to root cause, flux entrapment in the via holes. Short of changing the desing, here are sone suggestions. The main thing is you have to dry out the via holes of the wet flux. Some things to try are: slow down t
Electronics Forum | Wed Nov 28 18:24:05 EST 2001 | mparker
Back in the days when pots, skillets, etc. were made of cast iron, vegetable oils were used to "season" the iron to prevent rusting and also from the food sticking to the pot during cooking. It would be reasonable to believe that you could use the sa
Electronics Forum | Tue Jan 08 11:28:30 EST 2002 | mregalia
We use NC flux exclusively for SMT and wave soldering. And it is a fairly old formula from Multicore, though we are currently qualifying a new formula. The automated soldering does not appear to be a problem. It is only the hand soldering that causes
Electronics Forum | Wed Feb 13 09:49:30 EST 2002 | Phil the Quality Guy
Basically, the charge curve of a nicad cell isn't particularly linear. Your length of time is more dependant on the amperage rating of your cell. There's a difference between a 1.4 Amp and a 2.2 Amp capacity. As a nicad charges the bulk of the cha
Electronics Forum | Wed Oct 30 09:16:51 EST 2002 | russ
Low air flow huh. This is interesting, I have a low end machine that has adjustable air flow and I was having some shorting problems awhile back (corners mostly) and my first attempt was to preheat the board up to 170C and then use lower temp to put
Electronics Forum | Fri Nov 08 11:37:44 EST 2002 | jonfox
1. Back in the early days of consumer digital cell phones, we ran into the same problem. PCB with 2000 parts in a 5"x2" area, and double sided. We ended up using our standard vacuum tooling for the NIC side and stiff ESD safe foam for the NAC side
Electronics Forum | Mon Jan 20 22:39:46 EST 2003 | davef
Hi Stevo, Most paste suppliers say something like, �above 183*C for 45 to 60 seconds.� The problem we have with statements like that is that they seem to assume that the pads, component leads, and solder paste are all near eutectic 60/40 solder. A
Electronics Forum | Fri Jan 24 22:50:51 EST 2003 | MA/NY DDave
Hi Again Distance is tough, besides far less exciting.. You got the panther at your breast, screaming!! Somehow you have to make this go the other way. Rather than solder flowing any old place it wants to, when it wants to. Chasing the heat, Chasi
Electronics Forum | Mon Jan 27 14:16:46 EST 2003 | russ
i have done this thousands of times. You are correct about no preheat, however it never seemed to be any issue for us. You do have to make sure that you do not expose any SMT comps. to the solder or they will become heat stressed/fractured. Connec
Electronics Forum | Thu Feb 06 14:47:50 EST 2003 | MA/NY DDave
Hi "some customers/designers want to have via holes to be present in the PCB pad, due to some belief that it helps in heat dissipation. " As I think about this I don't know exactly why they would be concerned. I can imagine in some exotic products
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