FR-4 describes a class of standard temp laminate treated with di-functional epoxy. It has become a catch all phrase that is used (even by me) rather imprecisely for materials beyond it's orginal, technical description.

As you move up the laminate family curve in temp/Tg,you enter (and pass through) the land of multifunctional epoxies classified as FR-5.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Krug
Sent: Friday, May 12, 2017 4:52 AM
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Subject: [TN] FR-4 vs. FR-5

We've recently started the NPI process for a new assembly using FR-5 laminate.  A week ago I'd never heard of FR-5 and don't know much about it.  
	Does anyone have experience with FR-5?  
	Sources of laminate?  
	Key differences from FR-4?  
Then for my information, what would be the driver to specify this material?  

Any input on sources should be offline.  Thanks in advance.  

Dick Krug, CSSBB, CSMTPE
Lead Process Engineer
Sparton Brooksville, LLC
30167 Power Line Road
Brooksville, FL  34602-8299
(352) 540-4012
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