What about Legend?
Possibly not that well controlled though?
Rex
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Thayer, Wayne - IIW
Sent: 28 March 2011 13:53
To: [log in to unmask]
Subject: Re: [TN] Solder Joint Height Control
Hi Dale-
I've responded with a different subject name because that is how TechNet
keeps track of the threads.
I think you're doomed without a process engineer, because I don't
believe there is a fixed answer to your query. The simple approach is
to "try" a thicker stencil, but frequently that makes no difference with
a big heavy part having only 2 leads. So you may have to put something
underneath to get a required joint height. That's really complex
because it would be simple to put something beneath there that destroys
reliability. Someone used to make a spacer for apps like that which
dissolved in the post-soldering cleaning process, but I haven't used
them in the last 20 years, so I can't tell you where to find them.
Wayne Thayer
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Dale Hart
Sent: Monday, March 28, 2011 8:36 AM
To: [log in to unmask]
Subject: [TN]
Technet Folks
I'm not a process engineer, sooo how would one go about increasing the
solder joint height (G dimension) under a component. The company's
components generally have a height of 10 -20 um. The screen thickness
is 6 mils. The solder is 62Sn 36Pb 2Ag not sure about the flux,
particle size, storage time between printing, pick and place, and
convection reflow, if that is important.
The chip resistors are about 2012, caps 3225, with SOP16 (copper lead
frames).
Didn't actually measure the pad size but visually they appear properly
sized for the various components. The pick n place machine is an older
type that uses a spring loaded head and they program each component
height into the machine.
Dale Hart
Universal Technology Corporation
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