I am having trouble with aluminum bonded panels warping during the adhesive cure process. Parts are aluminum thin skins with aluminum honeycomb core and are eventually assembled into lightweight aircraft interior doors. I remember hearing about issues due the temperature difference between the top and bottom skins during curing. Anyone know anything about this ??
Is there a way you can fixture the parts during curing? Is your bonding adhesive shrinking and causing the warpage?
I have had similar issues with flat composite fabricating after post cure. Without heat cure (At room tempt) they were flat but, after evelated temt cure they were warped. Swithced the resin with one of the best in the market + fixed the part during cure + equal heat at both bottom & top. Still got them warped.
Solution tip came from one of my suppliers. Symmetry at cross section.! If your panel is already symmetric or you are unable to revise it , then good luck . Other wise consider your core as an axis and treat same to either side. (From the center of the cross section; Either side suppose to look like mirrored image of the other side)
If a honeycomb panel is heated unevenly between the top and bottom surfaces, it will warp. Period. No amount of fixturing will prevent it (unless the fixture has no thermal expansion). If the aluminum panel is heated unevenly during cure, the skins will slode along the core and the hotter skin will bond at a more expanded state than the cooler skin. When you cool the panel, the hotter skin will contrat more and will cause bowing towarss that skin.