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Problems with diode during wave soldering

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#67249

Problems with diode during wave soldering | 13 September, 2012

Hi everbody,

I'm facing some soldering problems with a Diode (SMA) during wave soldering process. During this process almost all the time one of the component pads have no solder, according to the picture dsc000604 attached. Some considerations: * The profile is according to our flux and the pre heating temperature on the component before touching the wave is about 110°C and peak temperature on wave solder is about 262°C. * The process is lead free and we use SACx 0307 alloy; * The flux is a no-clean, low solids flux - ROL0; * As the diode is a SMD process, we are using the chip and lambda wave; * We tried to increase and decrease the temperature on the component, but we didnt have sucess; * We also tried to increase and decrease the flux amount, but nothing change; * We started using this component one week ago due to a cost reduction project. Before it we're using a melf component and we didn't have this kind of problem.

Did anybody already face this problem? Some suggestion will be welcome.

Thanks,

Manoel

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#67250

Problems with diode during wave soldering | 13 September, 2012

possible problem are loading orientation, solder flow cannot reach the pad portion due to trap of the body of the diode... or try to adjust turbulent but observe overflow... because turbulent are penetrate solder to pad and terminal of the diode.

hope advice help! art

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#67251

Problems with diode during wave soldering | 13 September, 2012

Hello,

I was looking at your photos of this diode. I have a two question and I'm sure it maybe a simple fix. One, Is the diode actualy touching the pad;reason I ask is, I see that theres excessive amount of adhesive underneth the part. Two, did you take in cosideration of the trace that runs underneth of the diode.(this type of solder is the easiest solder to use and you should have no problems with any flow) From my experiance as a wave operator is that sometimes it's usaualy the simple things that need to be fixed. Eliminate the obvious, Try using less adhesive and make sure the part is actualy touching the pad. I can see that when it was run through the wave process that the solder shows dewetting on the pad which means the solder was looking for something to attach to, hence the part not touching the pad. I hope that helps, please let me know if it worked if not I have some other ideas.

Thanks, Melissa

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#67255

Problems with diode during wave soldering | 14 September, 2012

Hi Arturo. Thanks for you reply. The board is being loading so that the wave bath touch the 2 pads at the same time... I increased the chip wave in a maximum accepted level... One more rpm on the pump the wave sill overflow the board... Thanks...

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#67256

Problems with diode during wave soldering | 14 September, 2012

Hi Melissa, thanks for you reply...

I'll increase the placement force on this component so that it touchs better the board pad. Maybe it couldnt help due to stencil aperture. Maybe I'll have to change it.

If you have more ideas, please share with me.

Thanks.

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#67261

Problems with diode during wave soldering | 14 September, 2012

just check if the pad and component terminal was traces of solder, if have? try to reduce preheat temp and solder bath temp... reason why solder not adhere because of component lead type, if more heat you apply solder flows and not completely adhere... or try to replace other maker of diode that much less in thickness...

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#67301

Problems with diode during wave soldering | 18 September, 2012

Hi Manoel,

I want to make sure I understand what you are talking about; reading the reply,along with your replys it almost sounds as if we are not talking about the same thing. In your picture I'm seeing a SMT diode correct? You are talking about this part coming out like this after it gose threw the SMT oven (the oven that bakes the solder paste to the part correct?) or are you talking about this part being run threw a solder wave machine and solder is pulling away from part? If your talking about this part coming out of the solder wave machine, raising, lowering the tempture will do nothing for this part, it will fall under your SMT oven and backup in the process of applying this part.Please advise of your process so that i can get a better understanding of what it is your doing or not doing.

Thanks, Melissa

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#67306

Problems with diode during wave soldering | 19 September, 2012

Hi Melissa,

We mount this component in the bottom side with adhesive epoxy and the solder is done on the wave solder machine.

During the wave solder machine, we have the problem as like the picture.. no solder in one of the pads...

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