TECHNET Archives

December 2004

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
"Creswick, Steven" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Creswick, Steven
Date:
Tue, 7 Dec 2004 13:16:00 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (87 lines)
Rod - Steve,

I realize that I am a little 'late to the party', but here are a few comments.

Yes, the castellation was a totally plated through-hole which had been cut.  Depending upon the thickness of the PWB and the thickness of the blade, the through-hole may have been elongated [If I cut a 0.5 mm dia through-hole in half with a 0.5 mm wide/thick saw blade, I will not have much of the original barrel left to create the castellation].  So one either offsets the cut [which would screw up an immediately adjacent similar widget] or has an elongated hole, or a 'street' and another hole for the next adjacent widget. .... I know that what I am saying is clear in my mind, but I hope it comes to you as clearly  :-)

It was easier for us to cut/punch/drill another nearby hole and make 2 saw cuts to separate adjacent segments, however.

Thinner PWB's = thinner saw blades allowed.

The unsawn PWB can be mounted to a sacrificial plate [glass, other laminate, etc] using a water soluble wax, or mounted on standard wafer [dicing] tape and diced on a standard wafer dicing saw [with appropriate blade of course].

Since PWB's tended not to be really smooth on the bottom surface, we tended to prefer the waxes for their better 'gripping' power.  Nothing worse than have a $0.50 widget popping up as the blade passed by, taking the expensive saw blade with it!   Sigh!

Your challenge will be in finding someone that wants to cut up your widgets for you - well.


On the other hand, I suppose that you could use the same layout approach [with streets] and V-score from both sides.  That would probably make your search for a supplier a lot easier than searching for one with diamond sawing capability too.... so long as you do not mind having exposed fibrous edges, etc.

Steve Creswick - Gentex Corporation

-----Original Message-----
From: Steve Gregory [mailto:[log in to unmask]]
Sent: Tuesday, December 07, 2004 8:56 AM
To: [log in to unmask]
Subject: Re: [TN] PTH cut in half to make SMT pads


Hi Rod!

I understand what you mean. I believe you are trying to say that you want castellated terminations for the little module that you are installing on a larger board.

I'm not a fab guy, but I suppose that would be one way to create them on a little module. You would probably need to make sure that there are other holes within the module, so that there is something to fixture them in place during routing...otherwise they might go flying all over the place when trying to route them out.

-Steve Gregory-

>Hi,
>
>Some surface mount modules that I bought are made from regular PCB
>material and the mounting pads seem to be plated through holes cut in
>half.
>
>I can't buy those modules anymore and the manufacturers have made lots
>of our product but without these modules.  I need to make an adaptor pcb
>and doing it the way the orignal modules were made seems to be the
>easiest.
>
>They are just PTH cut in half with a nice cutting tool aren't they? Or
>are they a PCB with half of the PTH on the PCB and the other half
>falling off the side?
>
>If I went to our rapid prototyping people with this on our PCB would
>they understand?  Do you understand what I mean?
>
>Rod.
>
>---------------------------------------------------
>Technet Mail List provided as a service by IPC using LISTSERV 1.8e
>To unsubscribe, send a message to [log in to unmask] with following text in
>the BODY (NOT the subject field): SIGNOFF Technet
>To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
>To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
>Search the archives of previous posts at: http://listserv.ipc.org/archives
>Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
>-----------------------------------------------------
>

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

ATOM RSS1 RSS2