Preheating of the area (PTH) is the key factor to achieve the soldering requirement

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From: Riccardo Inverardi <[log in to unmask]>
Date: 20 December 2016 at 2:47:15 PM SGT
To: [log in to unmask] <[log in to unmask]>
Subject: [TN] R: [TN] Vertical fill of solder in Supported Holes

Hi Deng, my first ever answer on TN:

You should take a look to IPC-A-610F-AM1 (Dec 2015), where (if memory
doesn't fails me) it is stated that the minimum vertical fill for components
with less than 14 pins, but with a connection to an inner thermal plane is
50%, provided that a 360° lead-to-barrel wetting is present in the solder
source side.

Have a nice day,
--
Riccardo Inverardi
INTEA ENGINEERING

-----Messaggio originale-----
Da: TechNet [mailto:[log in to unmask]] Per conto di Deng RongJun
Inviato: martedì 20 dicembre 2016 03:01
A: [log in to unmask]
Oggetto: [TN] Vertical fill of solder in Supported Holes

Hi all:

There have a big difference on Vertical fill of solder between
IPC-A-610/J-STD-001 E version and F version.  In the F version said that
Vertical fill of solder for component with less than 14 leads is 75%, and
Vertical fill of solder for component with 14 leads or more is 50% for class
2.  But in some case some holes connect to ground plane in many layers, they
are very difficult to get 75% vertical fill during wave soldering or hand
soldering.
My question are:
How to improve the process to increase vertical fill from 50% to 75% in
through holes which connect to many layers?
Why IPC do this change? Why IPC define 14 leads, but not 8 leads or 16
leads?


Best regards
Deng