Bob:
Attached are three pdf views of the proposed revised Eagle module, and open view, fully closed view, and a view w/o the PCB. It has been a lengthy day getting all of the darned 0.5mm cover bends correct and holes properly placed for full mating of the cover with the baseplate (such things as 0.581mm hole placement discrepancies - ugh!). If built from the drawings that can be made from these objects, there should be a good fit in the real hardware.
I do not presume as to what the "real" next step wants to be, as I do not propose to make the 2D drawings until the discussions have settled down to agree that this is what we collectively like, or at least collectively accept. Please advise.
'73, Dick Jansson, KD1K mailto:kd1k@amsat.org kd1k@amsat.org mailto:kd1k@arrl.net kd1k@arrl.net
Guys,
I assume the PCB mounts are the same swaged PEM hardware as in the prototype I have. Is that correct? In my prototype all of those standoffs are loose and can be rotated with light finger pressure. This is not good. Also, I'm wondering what the manufacturer's tolerance is on length. It would be a shame to have a nice flat baseplate and then add errors to the PCB flatness due to tolerance differences in the standoffs.
I'd also suggest cap head screws for attaching the PCB to the chassis instead of Phillips. My screwdriver has jumped out of the head and landed on the PCB several times. If that happened to a flight board we'd have no choice but to replace every component that could have possibly been damaged by the screwdriver as a precaution. I think cap head screws would make for a safer attachment since an Alan wrench is much less likely to jump out of the head during installation or removal.
73,
Juan - WA6HTP
On 10/16/07, Dick Jansson-rr rjansson@cfl.rr.com wrote:
Bob:
Attached are three pdf views of the proposed revised Eagle module, and open view, fully closed view, and a view w/o the PCB. It has been a lengthy day getting all of the darned 0.5mm cover bends correct and holes properly placed for full mating of the cover with the baseplate (such things as 0.581mm hole placement discrepancies – ugh!). If built from the drawings that can be made from these objects, there should be a good fit in the real hardware.
I do not presume as to what the "real" next step wants to be, as I do not propose to make the 2D drawings until the discussions have settled down to agree that this is what we collectively like, or at least collectively accept. Please advise.
'73,
Dick Jansson, KD1K
kd1k@amsat.org
kd1k@arrl.net
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Hi Dick,
It looks like you intend the PCB to go over the lip of the front of the base plate and screw to it. Any chance of doing the same on the sides? Might you put threaded holes along the sides for that purpose? The PCB would be more securely held along those sides and, more important to some applications, there would be better thermal conductivity from that part of the PCB to the frame of the box. You might also be able to eliminate some of the stand-off's which would allow more of the PCB for components.
Another thought, which might not be compatible with the first thought... I see that the box lid has "ears" that come down over the front (connector) plate and a screw through each of them. Any chance of reversing that and having the ears on the front plate with a screw through the cover from the side? That would help with space for connectors on the front plate a little.
Looking good!
Chuck
Dick Jansson-rr wrote:
Bob:
Attached are three pdf views of the proposed revised Eagle module, and open view, fully closed view, and a view w/o the PCB. It has been a lengthy day getting all of the darned 0.5mm cover bends correct and holes properly placed for full mating of the cover with the baseplate (such things as 0.581mm hole placement discrepancies – ugh!). If built from the drawings that can be made from these objects, there should be a good fit in the real hardware.
I do not presume as to what the “real” next step wants to be, as I do not propose to make the 2D drawings until the discussions have settled down to agree that this is what we collectively like, or at least collectively accept. Please advise.
’73,
Dick Jansson, KD1K
kd1k@amsat.org mailto:kd1k@amsat.org
kd1k@arrl.net mailto:kd1k@arrl.net
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Chuck:
These are all quite valid suggestions. On PCB mounting, the center supports will still be needed for the keeping of the self-resonance of the PCB up above the 200Hz area. These suggestions will be given consideration.
For Juan, using socket head cap screws certainly can be done, but I suspect that you are trying to use a very well worn Phillips screw driver. The ONLY Phillips screw driver has to be one with a hardened tip, such as those that are used with a magnetic hex driver tool. With these 4-40 screws if there is any wear in the Phillips recess that screw is waste basket material, and properly used you just cannot have enough torque to pop the tool without shearing off the screw head. This also tells me that your torquing of the screws has been unnecessarily high causing the standoff posts to lose their grip.
'73, Dick Jansson, KD1K mailto:kd1k@amsat.org kd1k@amsat.org mailto:kd1k@arrl.net kd1k@arrl.net -----Original Message----- From: Chuck Green [mailto:greencl@mindspring.com] Sent: Tuesday, 16 October, 2007 22.22 To: Dick Jansson-rr Cc: Bob Davis; AMSAT Eagle Subject: Re: [eagle] 125x180 Module Assembly
Hi Dick,
It looks like you intend the PCB to go over the lip of the front of the base plate and screw to it. Any chance of doing the same on the sides? Might you put threaded holes along the sides for that purpose? The PCB would be more securely held along those sides and, more important to some applications, there would be better thermal conductivity from that part of the PCB to the frame of the box. You might also be able to eliminate some of the stand-off's which would allow more of the PCB for components.
Another thought, which might not be compatible with the first thought... I see that the box lid has "ears" that come down over the front (connector) plate and a screw through each of them. Any chance of reversing that and having the ears on the front plate with a screw through the cover from the side? That would help with space for connectors on the front plate a little.
Looking good!
Chuck
Dick Jansson-rr wrote:
Bob:
Attached are three pdf views of the proposed revised Eagle module, and open view, fully closed view, and a view w/o the PCB. It has been a lengthy day getting all of the darned 0.5mm cover bends correct and holes properly placed for full mating of the cover with the baseplate (such things as 0.581mm hole placement discrepancies - ugh!). If built from the drawings that can be made from these objects, there should be a good fit in the real hardware.
I do not presume as to what the "real" next step wants to be, as I do not propose to make the 2D drawings until the discussions have settled down to agree that this is what we collectively like, or at least collectively accept. Please advise.
'73,
Dick Jansson, KD1K
kd1k@amsat.org mailto:kd1k@amsat.org
kd1k@arrl.net mailto:kd1k@arrl.net
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
My comment on this is that the way the housing is fastened on by screws on the side will present a problem and more or less remove most of the advantage of having a removable cover. If the module is mounted in the spacecraft and you need to remove the cover for a test or adjustment, You have to remove the module first since access to the screws on the side is blocked by adjacent boxes. It would be better if you could remove the cover by accessing from the top some way. Perhaps a top hat profile would be better.
Lou McFadin W5DID w5did@mac.com
On Oct 16, 2007, at 3:46 PM, Dick Jansson-rr wrote:
Bob:
Attached are three pdf views of the proposed revised Eagle module, and open view, fully closed view, and a view w/o the PCB. It has been a lengthy day getting all of the darned 0.5mm cover bends correct and holes properly placed for full mating of the cover with the baseplate (such things as 0.581mm hole placement discrepancies – ugh!). If built from the drawings that can be made from these objects, there should be a good fit in the real hardware.
I do not presume as to what the “real” next step wants to be, as I do not propose to make the 2D drawings until the discussions have settled down to agree that this is what we collectively like, or at least collectively accept. Please advise.
’73,
Dick Jansson, KD1K
kd1k@amsat.org
kd1k@arrl.net
<125x180 Module Assembly Open.pdf> <125x180 Module Assembly Closed.pdf> <125x180 Module Assembly w-oPCB.pdf> _______________________________________________ Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Hi Dick,
Lou raises a good point. It would be nice to be able to remove the cover without removing the entire module. I've been sitting here trying to remember those times when we had to do tests on modules already mounted in the P3D satellite. There were a few times but I don't recall all that many. Further, most of the times I recall, we had to remove the module anyway to get to the bottom of the PCB for probing. In your new design, not only would the module have to be removed but the PCB would have to be removed from the module to get to the bottom side. Still, the extra rigidity seems worth these restrictions. And with this design, there is no chance that the module you want into has another module stacked on top of it.
Although a smaller satellite, AO-51 not only had to have the PCB removed from the module to get to it's bottom, but you had to completely disassemble the entire satellite to get to the bottom module, something I had to do just a couple of days before we transported it to the launch site. I didn't like it, but in the end it really wasn't all that big a deal.
And the more I think about it, the more I like having the PCB extend over the sides of the frame. This would be difficult to do if you change the way the lid is mounted.
Finally, you don't show any measurements. I need to go out later today and buy an electric oven for curing conformal coatings on widgets for P3E. I'd like to get one big enough to hold the proposed maximum board size(s). I don't need exact measurements, but can you tell me something close?
Another "finally," did you make any measurements of Sub-D and SMA connectors to see that they can be mounted to the front bracket and into the PCB without their pins shorting to the base plate? Your drawing looks like this could be a problem.
Chuck
Louis McFadin wrote:
My comment on this is that the way the housing is fastened on by screws on the side will present a problem and more or less remove most of the advantage of having a removable cover. If the module is mounted in the spacecraft and you need to remove the cover for a test or adjustment, You have to remove the module first since access to the screws on the side is blocked by adjacent boxes. It would be better if you could remove the cover by accessing from the top some way. Perhaps a top hat profile would be better.
Lou McFadin
W5DID
w5did@mac.com mailto:w5did@mac.com
On Oct 16, 2007, at 3:46 PM, Dick Jansson-rr wrote:
Bob:
Attached are three pdf views of the proposed revised Eagle module, and open view, fully closed view, and a view w/o the PCB. It has been a lengthy day getting all of the darned 0.5mm cover bends correct and holes properly placed for full mating of the cover with the baseplate (such things as 0.581mm hole placement discrepancies – ugh!). If built from the drawings that can be made from these objects, there should be a good fit in the real hardware.
I do not presume as to what the “real” next step wants to be, as I do not propose to make the 2D drawings until the discussions have settled down to agree that this is what we collectively like, or at least collectively accept. Please advise.
’73,
Dick Jansson, KD1K
kd1k@amsat.org mailto:kd1k@amsat.org
kd1k@arrl.net mailto:kd1k@arrl.net
<125x180 Module Assembly Open.pdf> <125x180 Module Assembly Closed.pdf> <125x180 Module Assembly w-oPCB.pdf> _______________________________________________ Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org mailto:Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
participants (4)
-
Chuck Green -
Dick Jansson-rr -
Juan Rivera -
Louis McFadin