Brian,
You make a good point, I think. Many people seem talk about CTE almost as
if it's a constant in all directions. Yet it is important to know that, and
when, something expands more in one direction than in others, and by how
much. Is this lack of precision laziness, lack of awareness or complacency,
I wonder. Pedants rule, I say!
Peter
Brian Ellis
<b_ellis@PROTO To: [log in to unmask]
NIQUE.COM> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST
Sent by: Aero/ST Group)
TechNet Subject: Re: [TN] Cracking Chip Resistors
<[log in to unmask]
RG>
04/17/02 02:04
PM
Please respond
to "TechNet
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Please respond
to Brian Ellis
Peter
If you wish to be really pedantic, how about LCTE, as opposed to VCTE (I
learnt both of these at school, about 60 years ago)? You may think the
volume coefficient is the cube of the linear, but 'tis not, necessarily.
In amorphous molecular structures, it usually is, but it is rarely the
case in morphous ones, as X, Y and Z LCTEs are rarely the same (take
FR-4 as one example).
Brian
Dave Hillman wrote:
>
> Hi folks! I have ran into a problem which has me baffled and the extra 20
> ounces of Coke I consumed this morning didn't bring about any better
> thought clarity so I would like to bounce the problem off the minds of
> TechNet. I have been attempting to hand solder a chip resistor (50 x 100)
> but have immediate cracking of the resistor across the width of the
> component. The resistor is either Aluminum Nitride or BeO (I'm still
trying
> to find out which material). And yes, we are using proper soldering
> technique(s) and the resistor pad geometries are our standard dimensions.
I
> know that the typical resistor body material is Alumina. Has anyone had
> good or bad experiences in hand soldering AlN or BeO resistors? Have I
run
> into a material flexural strength issue?
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
>
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