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IPC-A-610 interpretation of wetting angle (Chapter5)

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#79193

IPC-A-610 interpretation of wetting angle (Chapter5) | 12 October, 2017

Hello everyone,

I would like to know how you interpret the wetting angle in chapter 5.

What is meant with: "...solder contour extending over the edge of the solderable termination area or solder mask..."

Thanks

ps I know what a solder mask is.

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#79194

IPC-A-610 interpretation of wetting angle (Chapter5) | 12 October, 2017

It is the two conditions pictured in IPC-A-610F, Figure 5-1 C, D.

In the old, simplier days, we wanted our solder connection to have:

* Low wetting angle

* Shiny metal

Today, the metal doesn't have to be shiny and the wetting angle can be a high as 90*. If fact, in some cases, the wetting angle can be greater than 90*. Those cases are when the solder extends over:

* Edge of the solderable termination area ... OR

* Solder mask

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#79195

IPC-A-610 interpretation of wetting angle (Chapter5) | 12 October, 2017

Thank you very much for your response.I would like to know in which cases this could be the case. We have a disagreement how to interpret this and I need a 3rd opinion.

Thank you very much for your help!

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#79197

IPC-A-610 interpretation of wetting angle (Chapter5) | 12 October, 2017

Please post some pictures so we can see what you're talking about.

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#79199

IPC-A-610 interpretation of wetting angle (Chapter5) | 12 October, 2017

> Please ost some pictures so we can see what > you're talking about.

OK here an example. I'm sorry for the bad quality - The picture is cropped and only one of two pictures that I had on the phone that I could use.

According to my supervisor, this is totally acceptable. In my opinion it is not because we accede the 90* wetting angle.

I think the IPC standard is talking about cases where a lead is bent over the edge of the land and the solder is "Pulled" outwards.

Would you share my opinion or am I wrong with this.

Thank you very much.

Regards,

Stefan

Attachments:

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#79201

IPC-A-610 interpretation of wetting angle (Chapter5) | 13 October, 2017

While I wouldn't be happy with this "Hershey's Kiss" appearing solder connection, I'd suck it up and and accept it as acceptable according to IPC-A-610F, Section 5.1

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