Subject: | |
From: | |
Reply To: | |
Date: | Fri, 9 Jan 2009 08:50:10 -0500 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Kevin, why not ask your supplier "why?" Maybe they have extra material of
a certain size, or need to make your order from 2 different material stock
sizes, etc... When you have a question about "why" from somebody, I would
feel I owe them to get their side.
BTW- We live by the same 10% rule, and most of our pcb documentation states
that same 10% standard you mention.
Lenny ERG www.ergpower.com
----- Original Message -----
From: "Kevin Glidden" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, January 09, 2009 8:42 AM
Subject: [TN] PCB thickness tolerance question...Am I losing it?
> We have a small PCB that is less than 2" x 2" square. Material is
> IPC-4101/21 FR4 with 2 oz copper. 2 layers. Finish is Tin-Lead HASL.
>
> Total thickness is specified as .040" +/- .005", and the supplier is
> requesting increase to .040" +/- .006". Is it me, or is +/- .006"
> excessive
> for a 2 layer .040" thick PCB? I was always taught a "rule of thumb" that
> the PCB thickness tolerance is +/- 10% of the specified nominal thickness.
> Is this a bad "rule of thumb"? Even +/- .005" is 12.5%! Is this a sign
> of
> a problem with the supplier's process?
>
> Thanks!
>
> Kevin Glidden
> Manufacturing Engineer
> Luminescent Systems Inc.
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 15.0
> 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 15.0
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
-----------------------------------------------------
|
|
|