Thank you Franklin!


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Franklin D Asbell
Sent: Wednesday, April 05, 2006 9:57 AM
To: [log in to unmask]
Subject: Re: [TN] ANOTHER pcb fab question...

It depends upon the material and final finish of product being routed.

Typically entry material is not used. Backup material is always used to
ensure the tool passes completely through the product and almost as
important the backup material will have channels routed to remove dust and
debris. Entry material may be used for certain materials (teflons and the
life) and especially for some immersion finishes to prevent scuffs or
marring which may be perceived as poor coverage by some customers.

Cellulose fiber/paper and phenolic are common materials used, corrugated
plastic is another choice although I've not used it, heard pros and cons.
Dosco products is a good source.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Kevin Glidden
Sent: Wednesday, April 05, 2006 8:41 AM
To: [log in to unmask]
Subject: [TN] ANOTHER pcb fab question...

As I walk farther down the PCB fab road, more and more questions come
up...Thanks to all in TN who are helping me out to learn more...

This question has to do with PCB routing.  When the PCBs are routed out to
final size, is it normal to use both a top and bottom "material" to ensure
the PCBs are flat and to ensure a clean cut?  I can guess that a bottom
material is necessary just to avoid cutting the table.  What are the
materials for this support material that is really sacraficial?  Who are the
suppliers?

Thanks again...


Kevin Glidden
Manufacturing Engineer
Luminescent Systems Inc.
4 Lucent Drive
Lebanon, NH 03766-1439
Tel # (603) 643-7766 ext. 3152
Fax # (603) 643-5947



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