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3D Printed Electronics Bay Brackets

Posted: Mon Apr 22, 2019 9:59 pm
by Aquaman33
Hi all,

I am thinking about building my first electronics bay and I have been playing around with a concept in SketchUp.

The idea is to 3D print 2 brackets that will sit at either end of the bay and will support 2 plywood panels.

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On the outside of the brackets will be plywood bulkheads.

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A threaded rod will run through the centre to hold it all together and will provide the strength.

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I am thinking that the plywood will be epoxied into the blue brackets. U bolts (used for shock cord attachment) will go through the both the plywood bulkheads and the brackets to told them together.

In the drawings I have used 6mm plywood, M5 threaded rod designed for a 4 inch rocket, but I could upscale this.

What I am aiming for is an ebay that sits centrally in the rocket (not offset) and has lots of room for electronics (on both sides). It seems that a single threaded rod and 2 plywood panels provides more mounting space, compared to 2 rods (either side) and a single plywood panel (in the middle).

The whole thing will be housed in LOC couplers with LOC Stiffies inside, so the tube will be quite strong.

I could 3D print the whole sled, but my printer doesn't have the capacity and I think plywood is a better mounting surface.

I am keen to get feedback from those with more experience than me.

Also if anyone has seen photos of something similar I am keen to see them.

Re: 3D Printed Electronics Bay Brackets

Posted: Tue Apr 23, 2019 12:05 am
by Digit
It looks like a good idea to me! PML use 3d printed plastic bulkheads to support a fibreglass sled in their intelicones and Missile Works make an entirely 3d printed sled I believe but it’s pre drilled to suit their products. Your idea could be interchangeable too (easily change sleds) if they’re not epoxied in.

Re: 3D Printed Electronics Bay Brackets

Posted: Tue Apr 23, 2019 10:45 am
by Aquaman33
Thanks Digit.

I like the idea of making the ply panels changeable.

I added these 3D printed walls (highlighted in orange) that would help retain the ply panels more securely, in place of epoxy.

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Screw holes could also be added to allow the bracket to be bolted/screwed to the ply if required.

Is there any reason why most ebays have 2 threaded rods? Seems structurally unnecessary unless its a really heavy rocket.

Re: 3D Printed Electronics Bay Brackets

Posted: Tue Apr 23, 2019 11:02 am
by Digit
It may help to distribute the shock load a little at separation, but primarily to stop the sled from being able to rotate around a single rod. which your design wouldn't allow anyway.

Re: 3D Printed Electronics Bay Brackets

Posted: Sun Apr 28, 2019 8:21 pm
by Flying High
Aquaman33 wrote:.......
I added these 3D printed walls (highlighted in orange) that would help retain the ply panels more securely, in place of epoxy.
.......


Why add walls when the sled is retained radialy by the AV bay cylinder?
Cheers,

Re: 3D Printed Electronics Bay Brackets

Posted: Sun Apr 28, 2019 11:29 pm
by Digit
This design could be used in very large diameter av bays. Would save having to have extra wide sleds for no reason.

Re: 3D Printed Electronics Bay Brackets

Posted: Tue Apr 30, 2019 3:50 pm
by Aquaman33
First prototype has finished printing.

Plywood fit is nice and snug.

Just waiting for stainless hardware to arrive so I can test the hole tolerances.

It feels quite strong but I may add some strategically placed fillets to toughen it up a little.

So far so good.

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Re: 3D Printed Electronics Bay Brackets

Posted: Tue Apr 30, 2019 4:13 pm
by Aquaman33
Flying High wrote:
Aquaman33 wrote:.......
I added these 3D printed walls (highlighted in orange) that would help retain the ply panels more securely, in place of epoxy.
.......


Why add walls when the sled is retained radialy by the AV bay cylinder?
Cheers,


The inside diameter of the LOC Stiffy is 90.3mm. I had designed these brackets to be 86mm wide. This leaves about 2mm either side to make it easy to get the bay in and out. Keeping in mind that the ends are quite square and the tube is round.....a design flaw perhaps.

If I increased the width to say 89mm and rounded the ends I could rely on the cylinder to retain the plywood and the walls would be redundant.

However the bay would be more likely to fall apart when it is removed from the tube. Tension on the rod would be the only thing holding it together.

If you really want to maximise the plywood surface you could use wider panels and notch out the ply where the end walls are.