Bill,
This is a sheet for UL's on file listing; I removed the company's name,
and deleted a lot of their certs .... just picking some to show you what I
mean. I also removed the specific material abbreviation and kept only the
first letter then added "xxxx" - so no one can recognize any materials,
patterns, and so forth.
(I hope this comes out; it is a table, so I don't know if it will get
hosed somewhere along the path to your screen from mine ...)
Notice the column for Max Oper Temp C (Maximum Operating Temperature);
Notice how every laminate cert for this fabricator has it's own MOT ...
how the MOT ranges from 105C for some materials and constructions to 160C
for others. Notice how for V-0 (flamability class) there is a 105C, 130C,
and a 160C that all have a V-0 rating; notice that there are two flame
class ratings, V-0 and V-1, for identical MOT at 160C. One other comment:
notice that UL does not list the Tg. UL is very complicated.
These are the definitions for MOT and Flame Class as provided by UL:
http://www.ul.com/onlinetools.html
Maximum Operating Temperature ? The maximum continuous use temperature that the printed wiring board
may be exposed to under normal operating conditions.
UL 94 Flammability Classification ? Processed printed wiring boards with or without applied coatings,
finishes, etc., as supplied to the device or appliance manufacturer, may
be tested and classified in accordance with the Standard for Flammability
of Plastic Materials for Parts in Devices and Appliances ? UL 94, at the
option of the manufacturer.
Going back to the original question: the requestor needs to find out what
is the MOT for the material they intend to use; the best source for that
information is the supplier (assuming the designer knows the supplier
and/or has a contact in another department who can identify the supplier
and pose the question and get the information). He/she wants a material
rated with an MOT of 130C, obviously not one for 105C, when the
environment will be 120C.
Cond Width
Max
Max
Min
Cond
Area
Solder
Oper
Meets
C
Min
Edge
Thk
SS/
Diam
Limits
Temp
Flame
UL796
T
Type
mm(in)
mm(in)
mic(mil)
DS
mm(in)
C
sec
C
Class
DSR
I
Multilayer printed wiring boards.
Cxxx
0.03 (0.001)
0.05 (0.002)
17 (0.67)
DS
50.8 (2.0)
260
20
160
V-0
-
-
Cxxx
0.03 (0.001)
0.05 (0.002)
17 (0.67)
DS
50.8 (2.0)
260
20
160
V-1
-
-
Exxx
0.25 (0.010)
0.25 (0.010)
17 (0.67)
DS
50.8 (2.0)
260
5
105
V-0
All
-
Hxxx
0.03 (0.001)
0.08 (0.003)
17 (0.67)
DS
152.4 (6.0)
260
20
130
V-0
-
-
Hxxx
0.05 (0.002)
0.15 (0.006)
17 (0.67)
DS
152.4 (6.0)
260
20
140
V-0
All
-
Mxxx
0.15 (0.006)
0.18 (0.007)
4.3 (0.17)
DS
152.4 (6.0)
260
5
105
-
All
-
Nxxx
0.05 (0.002)
0.1 (0.004)
17 (0.67)
DS
152.4 (6.0)
260
20
105
V-0
All
-
Nxxx
0.05 (0.002)
0.05 (0.002)
17 (0.67)
DS
152.4 (6.0)
260
20
130
V-0
All
-
Bill wrote:
Interesting information Valerie... thank you.
I would not presume to 'know more' but I do have some observations from my
experience with UL. UL, in my experience, does not certify the operational
performance of the product... They don't care if it fails or not... They
DO
certify that WHEN it fails... that it does NOT cause a fire or shock
hazard.
I was not aware of a MOT or Maximum Operating Temperature certification
from
UL on printed circuit boards so this is news to me. Perhaps you have a
reference on the internet I can check to learn more about it?
Bill Brooks - KG6VVP
PCB Design Engineer, C.I.D.+, C.I.I.
---------------------------------------------------------------------------------
DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF DesignerCouncil.
To temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL)
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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
---------------------------------------------------------------------------------
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
|
