Thermal effects on PCB Thru Holes

[SteveBull]

Does anyone have any experience of the effects of thermal contraction/expansion on plated through holes in PCB (PWB) assemblies.
I appreciate that whilst expansion due to excess heat or shock caused by rapid heating can cause fractures in the copper barrel of a circuit board, it is unclear if there are any complications caused by the sort of sub-zero temperatures that can be endured by assemblies used in aviation (or even in the hold of an aircraft on long haul flights).
I would be extremely grateful for an answer on this one, from anyone with relevant experience.

Regards,

Steve Bull
Quality and Circuit Engineer

 

[SethN]

Steve
I work in the high frequency circuit industry and see a lot of aviation applications. I know first hand that teflon based circuit materials perform flawless at low temperatures. I cannot speak for the performance of other types of substrates.

Seth Normyle
Process Engineer

 

[jbartos]

Suggestion: The plastic around metal is O.K. The plastic inside metal is not O.K. since the plastic expands more than metal. The plastic pipes are always mounted on the metallic conduits or fittings. See for example, the plastic pipe service drop to the electric meter. The plastic conduit is not mounted inside the metallic meter socket hub. Thermal expansion and thermal contraction will have effect on any metal holes or other geometric forms inserted in the plastic PCBs.
The proper way to do it is to analyze it and model it by software.

 

[SteveBull]

Seth, Thanks for the post,
JBartos....I'm not sure what you are talking about. Plastic is not one of the materials that makes up a PCB, also metal holes are not inserted into a PCB, they are electroplated after the drilled substrate has been 'seeded' or catalysed, usually with carbon or electroless copper.
Anyone who can give me further information relating to the effects of extreme cold on the plated through holes of PCBs (especially in rigid Multilayer FR4 builds), please post.

Thanks,

Steve Bull
Quality and Circuit Engineer
Steve Bull
Quality and Circuit Engineer.

 

[jbartos]

Suggestion: Visit

http://www.mentor.com/pcb/seminars/...om_bonus_468x60_sdd_expedition_design_seminar

http://www.apcircuits.com/html/p1_laminate.html

http://www.pcbfab.com/

etc. for more info