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Date: | Fri, 28 Apr 1995 16:12:00 +0100 (WET DST) |
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John,
There are times when the metric system makes things seem very complicated !
The new version io IPC-A-610, (revision B) refers to solder balls of
0.13mm diameter etc.
The imperial way was a little easier to remember: (I call it the 5 ball
system!)
- No more than 5 balls per square inch allowed
- Solder balls cannot be greater than 5 mil (0.005in)
- Solder balls cannot be less than 5 mil from the nearest land or trace
This is the same as the requirement in IPC-A-610B, but easier to remember.
Note: I have come across a few situations where people are playing '8 ball'
(i.e. 8 balls/sq in, of <=8 mil diameter and >= 8 mil from conductors).
This is particularly the case with some companies who have been
struggling to come to grips with the new no-clean fluxes.
I hope that this helps...
Brendan McCormack
Senior Interconnect Engineer
AMT Ireland
Electronics Manufacturing Centre
University of Limerick
Limerick
Ireland
Ph. +353 61 331588
Fx. +353 61 330316
EM. [log in to unmask]
Origional message follows.....................
On Tue, 25 Apr 1995 [log in to unmask] wrote:
> Hi,
>
> Does anyone have any details of specifications as to the acceptability of
> solder balls on a finished board which details ball count per square inch,
> maximum ball size etc.??
>
> Thanks in anticipation.
>
> John Burke.
> -------------------------------------
> Name: John Burke
> E-mail: [log in to unmask] (John Burke)
> Compuserve: 100575,2301
> 04/25/95
> 08:34:21
> This message was sent by Chameleon
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