On 11/11/2014 7:09 PM, John Davis wrote:
On 10/29/2014 1:21 PM, wrote:
gareth wrote:
Other than for interconnects, how often are flexible circuit boards
needed?
Well, one advantage of a flexible board design, I suspect, is impact
resistance, with just a bit of padding inside the case you could make a
radio you could play baseball (it would be the ball) and expect it to
survive... Hard PC boards can get cracked and broken by that kind of
impact.
Short alleged true story is a police officer chasing a suspect, Drew his
Motorola hand held and threw it striking suspect in the back of the head
and knocking him down,, Officer then went up, applied a matched pair of
nice shiny steel bracelets, Picked up the radio and radioed for a
transport car.
Not the most impressive story about those HT's I have, but a good one
for this post.
Lol. I used to work for a company that made military radios. They took
a heck of a beating... in the factory! Then the soldiers weren't so
gentle with them either. Every one had FR4 PCBs in them. Once a radio
saved a soldier's life by stopping a bullet... but the radio didn't
survive.
The problem with any PCB is not the FR4 material when it comes to shock.
It is the solder joints. Bang a surface mount chip enough and the
solder lets loose. That's why mil spec gear is exempt from the RoHS
restrictions. The lead in the solder makes is more flexible and more
tolerant of shock. But it will still let go before the PCB breaks if it
is shocked enough times.
--
Rick