Bob,

Good explanation. 

I think a lot of people don't understand the difference between using UL 
rated materials (e.g. UL 94V-O) to build boards and applying a 
manufacturer's UL mark to the board. 

Having worked in a board shop that maintained a UL file, I think the main 
point you allude to regarding the board shop's UL file procedure is 
important. That file represents the board shops' procedure for building 
boards and includes board materials, as well as soldermask and legend inks 
that UL has tested per the applicable UL specification and approves. The 
procedure also includes maximum temperatures and bake cycles that the 
board / panel will be exposed to during processing. 

I agree with all other comments posted. 

Alan 

Alan D Exley
Principal Quality Engineer
Engineering Design Quality
Raytheon Space and Airborne Systems

310-647-4016 office
949-701-0072 cell
310-607-7363 fax
mailto:[log in to unmask]
 
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From:
Bob Neves <[log in to unmask]>
To:
[log in to unmask]
Date:
11/03/2009 05:05 PM
Subject:
Re: [IPC-600-6012] UL marking on pwb's
Sent by:
IPC-600-6012 <[log in to unmask]>



Hello Jose,

UL marking is a way for you to demonstrate that the marked boards are
manufactured in accordance with the procedures listed in your UL file for
the approved grade designation being marked.  This then allows a much
simpler UL compliance procedure for your customer.

That being said, UL marking is "necessary" only on boards that go into UL
listed products.  Unfortunately many manufacturers have both listed and
unlisted products and many time just require "blanket" UL ratings on their
boards so they do not have to track which boards require or don't require 
UL
listing.  This means that many boards you are asked by contract to mark,
actually do not require UL marking or go into UL listed product.

The down side to marking "all" boards is that if you mark it you are 
stating
that the boards meet all the UL requirements for the grade designation
marked and have to document that fact internally.  Many PCB manufacturers
mark 100% of their boards because it is easier than tracking who does or
does not require UL marking.

Bottom line... Only boards that go into UL listed products are required by
UL to be marked.  Your customer may also require marking by contract, but
other than that you are not required to mark "ALL" boards.

Best Regards,

Bob Neves
Chairman/CTO
Microtek Laboratories
[log in to unmask]
www.TheTestLab.com 
Anaheim, CA
+1 (714) 999-1616
Changzhou, China
+86 (519) 8548-7805






On 11/4/09 8:28 AM, "Jose A Rios" <[log in to unmask]> wrote:

> is UL code marking a requirement on all pwb's by default??
> or only when procurement documentation requires it ??
> 
> Joey Rios
> PWB & Process Quality Eng'r
> Endicott Interconnect Technologies
> 1093 Clark St.
> Endicott, NY 13760
> Office: 607-755-5896


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