摘要 |
A method of joining together in sandwich manner a unit comprising a first metallic sheet and a second metallic sheet with a cellular metallic core between them is effected by welding the first sheet to suitable prominences on the cell walls of the core and brazing the second sheet to the core in such a way that brazing material enters and so reinforces the corners of the cells but is not permitted to flow on to the first sheet. The unit constitutes an acoustic panel in which the first sheet is an acoustic sheet which is welded to the prominences on the cell walls of the core while the second sheet is brazed to the core with brazing material having been caused to flow into corners of the core cells to reinforce said corners and effectively secure the second sheet to the core, but without the braze material having been permitted to flow on to said acoustic sheet.
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