By disaster I think that we mean delamination and charring of the board. As the FR4 begins to decompose its by products are the evolved gases which are created as the larger chain molecules breakdown. As this process progresses the board starts to lose weight.
By increasing the Td I believe that the assumption is that while you'll never really go out this high in temperature in your process, you also will push-out the early signs of disaster which may become evident as measeling.
As some point the laminate is supposed to start out gassing anyway, right ? That's what the fire retardant built into it is supposed to do, correct? I assume that there are different fire retardants that begin to decompose at different temperatures depending on the chemistry used?
Does anyone follow the halogen free forum? Is this type of matter typically and better addressed there?
Rich K. / KEDS
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Nitin Kothari
Sent: Tuesday, August 10, 2004 3:45 AM
To: [log in to unmask]
Subject: Re: [LF] Tg material
Dear Victor,
How reliability is getting affected due to weight loss? Could you please be more specific about "Disaster"?
Thanks,
NK
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]]On Behalf Of Lee Parker
Sent: Tuesday, August 10, 2004 12:12 AM
To: [log in to unmask]
Subject: Re: [LF] Tg material
Victor
If you loss 5% of the laminate during assembly it will obviously be a disaster. This can be prevented by selecting a material that has a Td high enough to be compatible with your assembly environment.
Best regards
Lee
-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Monday, August 09, 2004 12:05 PM
To: [log in to unmask]; [log in to unmask]
Cc: [log in to unmask]
Subject: RE: [LF] Tg material
Lee,
How will the Td 5% weight loss effect the integrity of the laminate.
Victor,
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Lee Parker
Sent: Monday, August 09, 2004 10:58 AM
To: [log in to unmask]
Subject: Re: [LF] Tg material
Pascal
Td is the temperature that will cause a 5% weight loss in the material
Best regards
Lee
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Pascal Guiheneuf
Sent: Monday, August 09, 2004 9:38 AM
To: [log in to unmask]
Subject: Re: [LF] Tg material
Joe,
Td for PCB is thermal decomposition temperature (generally >320°C). Is anyone able to give a complete definition ? Merci,
Pascal
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Lee, Joe [CAR:CP12:EXCH]
Sent: lundi 9 août 2004 14:43
To: [log in to unmask]
Subject: Re: [LF] Tg material
Lee:
What is Td materials?
Joe
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Lee Parker
Sent: Saturday, August 07, 2004 11:31 AM
To: [log in to unmask]
Subject: Re: [LF] Tg material
John
Accounts are moving to both high Tg and Td materials to accommodate the higher assembly temperatures.
Best regards
Lee
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of John Foster
Sent: Friday, August 06, 2004 8:15 PM
To: [log in to unmask]
Subject: [LF] Tg material
I am curious if people have been automatically moving to higher Tg laminates to support lead free.
Any input would be appreciated
Thank You.
We are just starting down the lead free path and this forum has been a great help.
Thanks again
John Foster
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