Although Isola had published the announcement quoted below, alluding to the termination of manufacturing FR406, they now seem to be backpedaling a bit and state that it is still available.  Perhaps someone let the cat out of the bag a bit early???

Reports from PCB manufacturers continue to pour in stating in simple terms that FR406 is either extremely limited or completely unavailable.  These PCB suppliers are recommending that design staffs change specifications to a KB material with Tg 170 or to the ShengYi equivalents.  Those alternative products are readily available and typically as a lower cost.

And from the land of brass-balls, some Isola staff are threatening legal action for making the public aware of this situation.  Makes one wonder about the viability of their entire organization.


Originally published as “Prepare for demise of Isola FR406: ”

Important Notice from Isola:

The Printed Circuit Board Industry has been transitioning to RoHS PWB’s in accordance with the 2006 European directive. Part of this transition is the use of lead free solder in the assembly operation, these solders have up to 50oC higher reflow temperatures. By the end of 2016 most RoHS exemptions will have expired and PWB’s will have to survive the lead-free assembly process.

As a result Isola is discontinuing regular production of their FR406 laminate family; this material will still be available for an undetermined time, but at increased cost, increase material lead-time and with minimum order requirements.

Current specification:

CTE Z-axis Tg Td Dk Df
FR406 3.5 170 300 3.93 0.0167



We are offering Isola 185HR as the primary replacement for FR406 to be used on new and existing designs. The 185HR laminate is a NEMA/ANSI grade FR-4 laminate and is even more tolerant of lead-free assembly operations than FR406. Please be aware that orders that were previously fabricated on FR406 that specify a material requirement of “FR4” or “IPC-4101” (including Rev. C, Rev D, and Rev D-WAM1) slashsheets /98, /99, /101 or /126 may be fabricated on Isola 185HR laminate or Isola 370HR at our discretion. This would also apply to orders with the same IPC-4101 references but calling for /21, /24 or /26 with a fabrication document/print revision date of 12/31/2016 or prior. Orders calling for slash sheets /21, /24 or /26 with fabrication document/print revision dates after 12/31/2016 will require a deviation allowing the use of 185HR, 370HR or another alternative to FR406.

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