Chris,
You didn't specify the component. And the alloy. For instance, C4 joints almost always look like column. An image would help.
Regards,
Vladimir
SENTEC
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (416) 899-1882
Fax: (905) 882-8812
www.sentec.ca
-----Original Message-----
From: Chris Mahanna <[log in to unmask]>
Date: Mon, 1 Mar 2010 21:26:50
To: <[log in to unmask]>
Subject: Re: [TN] BTC rework, Square SJs
Thanks Werner. Gotcha. BTCs will keep us in business for awhile.
My biggest concern on this job is that the customer is going to ask "what's up with the funny shaped joints?".
It sounds like Bev has the T-shirt already.
I sent a picture to Steve.
Chris
From: Werner Engelmaier [mailto:[log in to unmask]]
Sent: Monday, March 01, 2010 1:56 PM
To: Chris Mahanna; [log in to unmask]
Subject: Re: [TN] BTC rework, Square SJs
Hi Chris,
The problem with this SJ is the low solder joint height 9=reduced reliability) and the stress concentration geometry from SMD.
Werner
-----Original Message-----
From: Chris Mahanna <[log in to unmask]>
To: Werner Engelmaier <[log in to unmask]>; [log in to unmask] <[log in to unmask]>
Sent: Mon, Mar 1, 2010 1:08 pm
Subject: RE: [TN] BTC rework, Square SJs
In cross section, the vertical sides of the joint are straight. I assume it has more/less retained the shape of the [trapezoidal?] stencil.
Chris
From: Werner Engelmaier [mailto:[log in to unmask]<mailto:[log in to unmask]>]
Sent: Monday, March 01, 2010 12:52 PM
To: [log in to unmask]<mailto:[log in to unmask]>; Chris Mahanna
Subject: Re: [TN] BTC rework, Square SJs
Chris,
What do you mean by "square joints?"
Werner
-----Original Message-----
From: Chris Mahanna <[log in to unmask]<mailto:[log in to unmask]>>
To: [log in to unmask]<mailto:[log in to unmask]>
Sent: Mon, Mar 1, 2010 12:15 pm
Subject: [TN] BTC rework, Square SJs
Are square joints simply due to the small mass of the components, or is it
possibly an indicator of insufficient heat? We have no indication that any of
the paste didn't flow. Wetting looks good. All evidence is from microsection.
Thanks,
Chris
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