Evamaria Jones
Quality Assurance Specialist
Electronic Manufacturing Skills Instructor
General Dynamics Information Technology
(703) 874-6796 direct
(540) 522-8823 cell
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________________________________
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Tue 5/29/2007 12:53 PM
To: [log in to unmask]; Jones, Evamaria
Subject: RE: [TN] Fw: Status of IPC Solder Inspection Criteria
Hole fill is 50% for Power/Grounds and 75% for signals.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jones, Evamaria
Sent: Tuesday, May 29, 2007 8:26 AM
To: [log in to unmask]
Subject: Re: [TN] Fw: Status of IPC Solder Inspection Criteria
What IPC class?
Evamaria Jones
Quality Assurance Specialist
Electronic Manufacturing Skills Instructor
General Dynamics Information Technology
(703) 874-6796 direct
(540) 522-8823 cell
[log in to unmask]
www.gdit.com
<https://owandhm.gd-ns.com/exchweb/bin/redir.asp?URL=http://www.gdit.com
/>
________________________________
From: TechNet on behalf of Joel Alexander
Sent: Tue 5/29/2007 9:18 AM
To: [log in to unmask]
Subject: [TN] Fw: Status of IPC Solder Inspection Criteria
I apologize for the email chain but I wanted to get your opinions on
criteria for supported hole solder fill and pad wetting. At the end of
the day I will provide the customer with what they want but I wanted to
get your opinions on the IPC-A-610 interpretations.
---
Joe,
IPC do differentiate between wetting and solder fill.
75% solder fill in the hole is acceptable
180 degree top side wetting from lead to barrel is considered
acceptable.
To clarify, the 75% fill is true as long as long you have wetting to the
top side lead to barrel transition and "0" wetting to the copper pad.
Eli,
For class 2 product, you need at least 180 degrees of circumferential wetting , observable in the hole, on the primary side. That solder, if properly wetted, bonds the lead to the to the barrel in a supported hole confiquration. Note picture 7-115 on page 7-54 that shows 100% fill but a black ring around the lead. Just because you have solder present doesn't mean it is wetted or bonding the component to PTH barrel. That condition is a defect; because, it doesn't meet the 180 degrees wetting on lead or barrel. The solder didn't bond to the finish on the lead (usually solderability, improper dwell, or thermal relief issues/heat sinking). Occasionally you will see that ring around the barrel...same defect...the solder didn't bond/wet to barrel.
Since you only need 75% fill or the exception of 50% fill for thermal planes, no solder is required to be present on primary side pad.
Eli,
It states lead to barrel not lead to land. If the fill requirement is
only
75%, then the land on the top side will not be wetted unless you have
100%
fill.
Joel Alexander
Quality Assurance Manager
Joe,
What about section B
Lead to pad transition on the primary side.
Eli,
I attached an extract from IPC-A-610 Rev D. Wetting between the lead to
land is a Target condition and should not be cause for rejection.
Let me know if you want to discuss this further and Bill can set up a
conference call.
Elie, I forwarded your email to our Quality Manager.
Bill,
There is a misunderstanding of the way you interpret the acceptance
criteria of the lead-free solder connection vs. ours. To my
knowledge, there should be a wetting between the lead to pad transition
on
the component side of the board. Your manufactured boards do not meet
this criteria. Please let me know how we can resolve this issue?
ForwardSourceID:NT000B7562
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