I have done this "half-a-hole" castellation on some .032 thick
fiberglass/epoxy material, multilayer... with very small vias and a 0.8mm
pitch BGA mounted to it...

We built the 'chip carriers' into a panel... and the board house routed out
the 1/2 a plated thru hole by drilling an extra hole tangent to the main
hole and then routing them in half.

There was some de-burring to do on some of them until they got the process
down...

There is a picture of the board on my website. Also check the FAQ area and
look at the close-up view of the castellation holes. http://pcbwizards.com

The shop that did the work for me is Hughes Circuits in San Marcos
California. Talk with Jerry or his son Jeff Hughes and they can explain the
process.


Bill Brooks - KG6VVP
PCB Design Engineer , C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
e-mail:[log in to unmask]
http://www.dtwc.com
http://pcbwizards.com


-----Original Message-----
From: Roderick Taylor [mailto:[log in to unmask]]
Sent: Tuesday, December 07, 2004 12:20 AM
To: [log in to unmask]
Subject: [TN] PTH cut in half to make SMT pads

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.

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