 
| Subject: | |
| From: | |
| Reply To: | DesignerCouncil E-Mail Forum. |
| Date: | Wed, 13 Jun 2001 08:01:45 +0200 |
| Content-Type: | text/plain |
| Parts/Attachments: |
|
|
Good morning Matthew,
we determine the minimal distance between SMT components by the allowable minimum distance
between component pads. Which in turn is calculated taking into account the minimum width for
solder-mask structures (appr. 0.15mm) and adding the size of the opening in the solder-mask
of the component pad (e.g. 0.075mm) times two. So that we arrive at 0.3mm distance between
pads for reflow soldering. For wave soldering the SMT component distance must be derived
from component heights because of shadowing effects. In this case a distance of 2.5mm between
centers for chip components of 0805 size will work fine.
Volkmar
------------------
Matthew Lamkin wrote:
> Hello everyone.....
> One of the varied managers that I have to work for has asked me the question
> of;
>
> "Why do you need to have a 1mm gap between SMT component pads?"
> "Can you get the components any closer?"
>
> My default placement outline on SMT components is 0.5mm (making 1mm when
> side by side), and
> placing components this spaced works fine, but when you take apart a mobile
> phone & see the placement on it
> we have to wonder if we can go closer?
>
> I'm sure that this is something that I have seen in the varied publications
> that I have read, something
> to do with preventing solder theft, thermal dissipation, preventing the
> placement machine hitting adjacent components etc
>
> Now as my reply determines the component pitch on what will be one of our
> highest volume boards, I'd like to formulate
> a very technical reply....
>
> So have you folks got any good comments on why?
>
> What can happen if I place them closer?
> How close can I place components these days?
>
> Incidentally we use Quad QSV1000 P&P and Reflow oven.
>
> Many thanks...
> Matthew Lamkin
> Printed Circuit Board Draughtsman
> Protec Fire Detection PLC.
> Churchill Way,
> Nelson, Lancashire,
> England. U.K.
> BB11 5JU.
> TEL 01282 717393
> FAX 01282 717273
> email mailto:[log in to unmask]
> (please always use this email address when replying to any of my messages.)
> The E-mail and any attachments hereto are strictly confidential and intended
> solely for the addressee.
> If you are not the intended addressee please notify the sender by return and
> delete the message.
> You must not disclose, forward or copy this E-mail or attachments to any
> third party without the prior consent of the sender.
> In addition, any opinions expressed in this E-mail are solely that of the
> sender and must not be taken as that of the senders employer.
>
--
Volkmar Hu Drger Electronics GmbH
Packaging and Interconnection Technology Kst. 3022
Aufbau- und Verbindungstechnik Moislinger Allee 53/55
Phone +49 451 882-3998
FAX -4365 23542 Lbeck / Germany
mailto:[log in to unmask]
------
Engineer: (v.) to build something with bugs (software) or glitches (hardware).
(n.) One who engineers.
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 07 ެ*.ȥƢ鮋u?jއ "?!$? N˛n z I4E<_D?~e^^p/9o 칸s߉] / cNzȠ¢܊ӯ *'h^+ޯ_('zw" HE
"w
r*?4
|
|
|
