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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Solder On Gold

Zambri

#11456

Solder On Gold | 16 May, 1999

I'm running memory module product- SMT double reflow ( 12 modules per panel). I'm using the epoxy base solder paste in order to reduce the flux spattering problem onto the gold finger which could lead to the intermittent contact problem.

I don't face much problem on flux spattering but lately solder on gold seems to be my biggest evil. FYI, I use pallet for my reflow ( which is also gone thru the frequent cleaning process ) to compensate the warpage problem. Pls help me to encounter this problem. My major suspect was from the ineffective underscreen cleaning but after a lot of effort/focus had been put in placed, the problem still exist. Pls, all the expert out there....hellllllppppppppp!!!

cheers.. zambri

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#11457

Shootenem from a-far | 16 May, 1999

| I'm running memory module product- SMT double reflow ( 12 modules per panel). I'm using the epoxy base solder paste in order to reduce the flux spattering problem onto the gold finger which could lead to the intermittent contact problem. | | I don't face much problem on flux spattering but lately solder on gold seems to be my biggest evil. FYI, I use pallet for my reflow ( which is also gone thru the frequent cleaning process ) | to compensate the warpage problem. Pls help me to encounter this problem. My major suspect was from the ineffective underscreen cleaning but after a lot of effort/focus had been put in placed, the problem still exist. Pls, all the expert out there....hellllllppppppppp!!! | | cheers.. | zambri | | Zambri

The problem with trouble-shooting from afar is if you don't have enough info it's difficult to offer solutions.

If the problem is on every board, then inspect the boards after every step in the process under a Scope until the solder shows up.

If the problem comes and goes like 1 out of 20 boards has the problem, then take a look at the handling of the boards, such as contaminated work surfaces, operators with solder paste on the hands etc. You can identify these operators by watching for nervous twitches (from too much lead in the blood); but then again it could be an engineer looking for solder on gold contacts.

And it wouldn't hurt to check the boards before running them to make sure the problem isn't coming from the board vendor.

Lot's of luck

Mike

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Glenn Robertson

#11458

Re: Solder On Gold | 19 May, 1999

| I'm running memory module product- SMT double reflow ( 12 modules per panel). I'm using the epoxy base solder paste in order to reduce the flux spattering problem onto the gold finger which could lead to the intermittent contact problem. | | I don't face much problem on flux spattering but lately solder on gold seems to be my biggest evil. FYI, I use pallet for my reflow ( which is also gone thru the frequent cleaning process ) | to compensate the warpage problem. Pls help me to encounter this problem. My major suspect was from the ineffective underscreen cleaning but after a lot of effort/focus had been put in placed, the problem still exist. Pls, all the expert out there....hellllllppppppppp!!! | | cheers.. | zambri |

| | Zambri -

Some people use Kapton tape to protect Gold pads during processing. Use an ionized air blower when the tape is removed to avoid ESD damage. This may nt be practical for you, but for what it's worth...

Glenn Robertson glenn.robertson@usa.alcatel.com

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KT

#11459

Re: Solder On Gold | 20 May, 1999

| I'm running memory module product- SMT double reflow ( 12 modules per panel). I'm using the epoxy base solder paste in order to reduce the flux spattering problem onto the gold finger which could lead to the intermittent contact problem. | | I don't face much problem on flux spattering but lately solder on gold seems to be my biggest evil. FYI, I use pallet for my reflow ( which is also gone thru the frequent cleaning process ) | to compensate the warpage problem. Pls help me to encounter this problem. My major suspect was from the ineffective underscreen cleaning but after a lot of effort/focus had been put in placed, the problem still exist. Pls, all the expert out there....hellllllppppppppp!!! | | cheers.. | zambri | | Zambri, run few bare boards through the oven and chech the gold fingers. If you saw anything have the them tested for composition,gold quality and thickness. Make sure the printer has been cleaned,old dried-up paste can get ariborn. Segreagate the miss-prints, wash and run them separately. Good luck. | | |

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