Rolled edges

[entx]

Okay this may be a redundant question, but I have a question about a term I see on composite parts that are geared towards automotive components, specifically hoods, decklids...etc...

I see a lot of marketing terms out there such as "silver carbon fiber", which is nothing more that Hexcel's Texalium...but anyway back to my real question...I see the term "rolled edges" which to me infers the parts have a finished edge buy leaving the first ply overhanging during the layup process and after the last layer is applied that first layer is wrapped over to finish the edge. Or am I looking into this too much as a marketing phrase in that the parts are nothing more than cut edges that have been sanded to produce the same rolled edge that would be on a typical body panel...

 

[MikeHalloran]

On a steel panel,

- a rolled edge comprises curling the cut edge into a nearly complete tubular cross section tangent to the panel surface. It's usually curled far enough that the cut edge is not easily touched. It's a traditional finish for toys made of very thin metal, and sometimes includes a wire trapped within the tube for buckling resistance.

- a hemmed edge comprises folding the cut edge on itself. In thin metal, you might occasionally find a double hem, which makes the cut edge inaccessible. On an assembly like a hood or decklid or door, the outer panel is folded over the inner panel, which is smaller, trapping the inner panel within the hem of the outer panel.

...

Since composites are flexible during layup, you can't make a rolled edge without a core, which could be wire or tubing, and could be withdrawn after cure.

... Or it could be somebody's marketing hype for a thick edge sanded to a radius.



Mike Halloran
Pembroke Pines, FL, USA

 

[entx]

That is pretty much what I was thinking as well...it has to be marketing hype because the time involved to literally roll the edge similar to sheet metal would be extremely time consuming...

Thanks

 

[Reidar77]

Mike: That is exactly what rolled edges are when talking about something like a carbon hood. Just a fancy way of saying "we sanded it".

Some guys like to mould lips into there car hood moulds. Also considered rolled edges, and the correct way of doing it. But 9 times out of 10 its what Mike said.

Jason