[eagle] Re: Revised Module Suggestion

Juan Rivera juan-rivera at sbcglobal.net
Mon Oct 15 08:37:47 PDT 2007


Dick,

That looks nice!  It appears to solve the issue of getting that front panel
at exactly 90 degrees to the baseplate and also increases the stiffness of
the baseplate.  Increasing the useful front panel space also eases the
problem of working around the CAN-Do PCB with all of the necessary I/O
connectors.

Would it be possible to customize the baseplate for the few modules that
draw high power?  It would be nice to machine the baseplate and heat sinks
as one chunk of metal instead of the existing method of having several
individual heat sink pieces.  I would like to see the PCB laying flat on top
of the baseplate with milled cutouts to accommodate any devices attached to
the bottom side.  In a perfect world there would be no components on the
bottom and the PCB would make contact with the baseplate across the entire
surface.  Another possibility that might be worth considering would be the
ability to include "U" shaped heat sinks that would bridge over the top side
of hot components and attach to the baseplate through holes cut into the PCB
on either side of the component.  Thermal gap filler could allow room for
CTE mismatches so that the device isn't crushed.

73,   Juan - WA6HTP


On 10/15/07, Dick Jansson-rr <rjansson at cfl.rr.com> wrote:
>
>  Bob:
>
>
>
> Shown in this message is a picture of the revised module design that you
> and I have been working on in the last few days. The revised cover has not
> yet been done but its features are implicated in this current view. The
> machined base plate has robust beams around three sides. Further, there are
> stiffening beams machined on the bottom side of the baseplate. The side to
> side dimension of the baseplate is shown at 141mm, reduced from its previous
> 147mm. This step was needed to accommodate the cover screw heads now on the
> side of the module.
>
>
>
> Shown also is a revised connector plate, which is increased in width from
> the previous 122mm to the 141mm of the baseplate. This should ease the
> connector space issue a little as the cover PEM nuts have accordingly been
> moved out leaving a 125mm wide clear space for connector activity, an
> increase from 106mm.
>
>
>
> The PCB is unchanged, however its standoff posts are now 6.4mm (1/4 inch)
> from the previous 4.8mm (3/16 inch), a step needed for connector plate
> screws.
>
>
>
> The cover will slide over the assembly shown and it will have only one
> flange, along the rear side. The long sides will use screws placed into the
> edges of the assembly (formerly a flanged side). This means that there will
> not be mechanical loading on the baseplate caused by irregular flange bends,
> as in the present cover design.
>
>
>
> Regarding this design of module, the PCB access has been fully maintained,
> but the cover cannot be removed while the module is installed into the
> spacecraft, a feature that had been planned with the current design.
>
>
>
> Discussion is invited.
>
>
>
> Dick Jansson, KD1K
>
> kd1k at amsat.org
>
> kd1k at arrl.net
>
>
>
> [image: 125x180 Module Assembly.jpg]
>
> _______________________________________________
> Via the Eagle mailing list courtesy of AMSAT-NA
> Eagle at amsat.org
> http://amsat.org/mailman/listinfo/eagle
>
>
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