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Design modification

Design modification

Design modification

So I come here in hopes of finding a better way a lid like this.

Overall manufacturing of the lid has been successful and we haven't had any major problems.
But with the last batch, some have bent because of the welding stresses, and they cannot be restored to the final shape.

I'll try avoiding welds, but I need to redesign it, in the most simple way, using nothing else but sheet metal, and keeping the shape it has.

I was thinking of bolting to the lid, the support of the central connection. I'm not sure of this because without the "arms" the lid will become quite "flimsy".

Any ideas on how to minimally but successfully improve this?

I could go and try methods on the go, but i cannot waste any more time. I'm even asking before designing anything.

RE: Design modification


If this thing is sheet metal, you can rivet everything. Solid flat head rivets can be made just about invisible under a coat of paint.


RE: Design modification


Riveting comes to mind for me as well.

If you are adding flanges anyway for riveting, spot welding might also be possible and might pose less of a heat input warpage problem.

RE: Design modification

I'll second spot welding.
Yes you would need tabs to allow this but that would be easy.
You could even bend the tabs to alternate sides in order to make things stiffer. The center ones one way and the outer ones the other.
I am guessing that you will need to have intermediate ones also.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: Design modification

This is all stainless steel.

Guess I'll have to go with bolting, or riveting. Making little tabs to bend om the arms and bolt into the main body of the lid was one of my ideas, but I was anyway trying to get second thoughts.

Dont have a spot welder that powerful around (2mm thick SS steel).

RE: Design modification

Another option is to use 1 mm thick skins and sandwich construction using adhesive. Most doors are made this way, using a Styrofoam core or paper honeycomb.

RE: Design modification

If the red dots are supposed to be where the broken welds are located, then, I would redesign the cross frame so as to have flanges incorporated into the four arms of the cross frame and then spot weld, as mentioned above, the flanges integrated into the cross frame against the flat sheet metal. Just remember that their could too much flexibility between the four arms of the cross frame and the flat sheet metal so you may have to increase the thickness of the cross arms.

RE: Design modification

Why don't you add some angle to the "arms" and then glue it? If it's that flimsy that welding creates issues it can't weigh much?

They glue airplanes together nowadays...

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