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Finishing Aluminum Honeycomb Edges.Helpful Member!(2) 

TxBxSx (Structural) (OP)
28 Jun 11 16:06
I am new to the concept of honeycomb panels and fairly oblivious to how it is usually handled. I am trying to figure out a way to create an aesthetically pleasing edge using aluminum honeycomb panels.

I would like to try and avoid having custom panels made, and would rather just buy full sheets, cut them to size, and finish and fasten the edges. Of course, in the most cost effective way.

Any experienced suggestions would be greatly appreciated.
Helpful Member!  ESPcomposites (Aerospace)
28 Jun 11 17:27
Do you mean edge closeout?

Try page 23,
http://www.hexcel.com/Resources/DataSheets/Brochure-Data-Sheets/Honeycomb_Sandwich_Design_Technology.pdf

There are other ways, but that may get you started.

Brian
www.espcomposites.com

TxBxSx (Structural) (OP)
28 Jun 11 20:49
Yes, exactly. I had thought about the box extrusion method, but wasn't sure as to how to trim back the core and epoxy clean enough to insert the extrusion. Obviously plenty of people are doing it, but I just assumed that it was being done when bonding the panel.

I was told by a guy I work with that used to work in aviation, that they would trim back the core and create a flange by just re-bonding the sandwiching materials together(flat against each other). I am still looking into this.  
TxBxSx (Structural) (OP)
28 Jun 11 20:54
I'm finding this very informative....Thanks for the link Brian!

http://www.hexcel.com/Resources/DataSheets/Brochure-Data-Sheets/Sandwich_Panel_Fabrication_Technology.pdf


Thanks for the link Brian!
 
ESPcomposites (Aerospace)
28 Jun 11 21:46
Sure thing. I forget about the separate fabrication PDF. I have a very old version (10+ yrs) that I actually prefer, which has both design and fabrication merged. They have since separated them.

Brian
www.espcomposites.com

TxBxSx (Structural) (OP)
29 Jun 11 20:17
If I were to go with the square extrusion method, how would I go about trimming back the core on the edges with out deforming the skins?  
Helpful Member!  berkshire (Aeronautics)
4 Jul 11 10:52
TxBxSx
Use a router table, with a fly cutter set to cut the core without damaging the skin.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them.  Old professor

TxBxSx (Structural) (OP)
4 Jul 11 13:49
Thanks for the tip. I have never used fly cutter bits before, but it seems there are a few different styles. I'll look into it further. And a router table seems like a solid way to run multiple edges in little time, as well as a economical for these small jobs.

It seems like you would be able to accomplish the same results with an end mill bit. Is there any reason this wouldn't work in the same set up?
rerig (Aerospace)
6 Jul 11 11:21
berkshire (Aeronautics)
6 Jul 11 12:36
You can do the same thing with an end mill, it is a little slower.
The end mill would have to work with the faces of the sheet vertical to the cutter. so you would have to construct a fixture that held the router at 90* to the edge of the sheet. this would be using a cutter shaped like diagram G in Rerigs data.
 By using a router table with a fly cutter, the sheet is flat on the table, the table fence is set to the plunge depth you require, and your only concern is stopping the sheet from lifting off the table and cutting the skin. this would be using a wider edge cutting version of a cutter like diagram F in Rerigs data.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them.  Old professor

TxBxSx (Structural) (OP)
6 Jul 11 13:16
Its amazing, I spent a solid hour searching different types of router bits the other day and somehow managed to not come across the rebating bits. It just goes to show how much more effective you can be if you know the proper terms and tags for everything.

Well it looks like its time to start shopping...Thanks.
49again (Aerospace)
2 Aug 11 11:43
We use some lightweight epoxy stuff from Loctite Aerospace - P/N TF-3056FR. We just use a metal block to push the bits of honeycomb back away from the edge a little, then mash the epoxy paste into the edge and smooth it with a putty knife. Pretty quick, and most importantly (since it's aircraft) very light. Plus, easy to go around rounded corners. Kind of a nice aqua-blue/green color too.

Steve R.  

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