Hi Charming,
After going through the list, till now, it seems every design related is ok. What is the outer copper thickness being used (1oz~4oz)?
You might want to retake the profile again to ensure that the heat distribution is good.
Regards
GA Tan
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Charming Chan
Sent: Tuesday, 4 November 2008 7:10 PM
To: [log in to unmask]
Subject: Re: [TN] How to improve solder filling and wetting contact angles for thermal PTH at wave soldering process.
Hello Ang,
Info as follows, sorry for late. Thanks.
a) What alloy is being used?
SAC305
b) What type of flux is being used?
Alpha EF-8000
c) What is the plating finish?
OSP, ENIG
d) What is the board thickness?
1.6mm generally
e) What is the pin-to-hole rate?
0.7874mm hole size, 0.55 lead size
f) Can you send me (off-line) the PTH design and connector Mfg P/N used?
0.7874mm hole size, 1.397mm pad size, 0.55mm lead size
Best Regards
Charming Chan
PCBA Engineer
"Tan Geok Ang" <[log in to unmask]>
2008-10-29 09:16
收件人： "TechNet E-Mail Forum" <[log in to unmask]>,
<[log in to unmask]>
抄送：
主题： RE: [TN] How to improve solder filling and wetting contact
angles for thermal vias at wave soldering process.
Can you provide with the following
a) What alloy is being used?
b) What type of flux is being used?
c) What is the plating finish?
d) What is the board thickness?
e) What is the pin-to-hole rate?
f) Can you send me (off-line) the PTH design and connector Mfg P/N used?
Thanks!
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Charming Chan
Sent: Wednesday, 29 October 2008 8:59 AM
To: [log in to unmask]
Subject: Re: [TN] How to improve solder filling and wetting contact angles
for thermal vias at wave soldering process.
Hello Ang,
Thanks a lot for your input. Please refer to the comments under your
proposals. We really did the work the same as you proposed but still poor
solder filling in the through hole barrel with thermal pad, and the
wetting contact angle exceed 90°.
Do any other assembly shops have the same issue? How to improve? Thanks.
a) Redesign the thermal pad grounding so that it is not fully contacted
with the thermal layer.
[Comments] In our design, to facilitate wave soldering, where a component
through hole is supposed to connect to copper plane, a thermal relief pad
is designed always.
b) At solder during the SMT process (ensure that the pin is still able to
insert into the hole).
[Comments] Yes, it is.
c) Increase the preheat to even out the whole board
[Comment] Tested with dip tester, the preheat temp. is about 120C, and the
conveyor is set at 80cm/min.
d) If the space/distance between chip wave and main is too far, do not
turn on the chip wave.
[Comment] Chip wave turn off.
Best Regards
Charming Chan
PCBA Engineer
Tan Geok Ang <[log in to unmask]>
发件人： TechNet <[log in to unmask]>
2008-10-28 22:00
请答复 给 TechNet E-Mail Forum; 请答复 给 Tan Geok Ang
收件人： [log in to unmask]
抄送：
主题： Re: [TN] How to improve solder filling and wetting contact
angles for thermal vias at wave soldering process.
a) Redesign the thermal pad grounding so that it is not fully contacted
with the thermal layer.
b) At solder during the SMT process (ensure that the pin is still able to
insert into the hole).
c) Increase the preheat to even out the whole board
d) If the space/distance between chip wave and main is too far, do not
turn on the chip wave.
________________________________
From: TechNet on behalf of Charming Chan
Sent: Tue 10/28/2008 8:25 PM
To: [log in to unmask]
Subject: [TN] How to improve solder filling and wetting contact angles for
thermal vias at wave soldering process.
Hello TechNet experts,
At the wave soldering process, the solder filling of thermal vias(the via
holes connected with copper plane by thermal pad) can not fulfill the 75%
acceptance spec in IPC-610D. Moreover, at the lead free wave soldering
process, the wetting contact angles of thermal pads exceed 90° often.
My question is how to improve solder filling and wetting contact angles
for thermal via holes? Thanks a lot.
Best Regards
Charming Chan
PCBA Engineer
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