Phil

Above all, do not be misled into thinking that silicone materials, being
rubbery, will transmit shock less. Nothing is farther from the truth:
many silicone rubbers are almost totally incompressible in the short
time scale. Any mechanical energy imparted to it by a short duration
shock will be dissipated almost entirely within the components, to their
obvious detriment (super-bouncing ball effect, where almost no kinetic
energy is dissipated in the rubber, allowing it to rebound multiple
times).

Brian

DUTTON Phil wrote:
>
> Hello Technetters,
>
> I am soon to design a PB for one of our customers that will be required to
> withstand a shock load of approximately 1500 g's.
> Does anyone have any guidelines or advice on how to achieve this?
> I'm thinking of solid potting the assembly within a rigid structure as one
> solution.
> Components are expected to include SMD discretes and BGAs.
> Of course there's the consideration of how hard the potting compound needs
> to be and what it should be (epoxy, silicone elastomer), as well as what
> material the board should be made of, CTE considerations between the board -
> components - compound - housing etc.
> Any advice would be most welcome.
>
> Phil Dutton C.I.D.
> Senior CAD Technician
> IPC Certified Interconnect Designer
>
> Tenix Defence Systems Pty Ltd
> Systems Division - Adelaide
> Second Avenue, Technology Park,
> Mawson Lakes.  SOUTH AUSTRALIA  5095
>
> ================================
> Phone   (08) 8300 4400 (reception)
>         (08) 8300 4481 (direct)
> Fax             (08) 8349 7420
> email           [log in to unmask]
> Internet Page   http//www.tenix.com
> ================================
>
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