Formed core sandwich structure and method and system for making same

Abstract

A method and apparatus for producing a metal core sandwich structure that is lightweight and many times stiffer than regular sheet metal, and which is easily formable into curved structures as well as structures having compound curves. In one embodiment, a formed metal core includes a plurality of cells comprising alternating front and rear projections extending outwardly in front of and behind a median plane, with each projection having a bonding surface area or land configured to be brazed or bonded with corresponding external metal sheets on both sides of the formed metal core. A plurality of micro-abrasions or indentations are formed on the bonding lands, allowing stronger brazing or bonding joints to be formed between the metal core and the external metal sheets by facilitating improved capillary action by the metal core during the brazing or bonding process.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application is a continuation-in-part of U.S. application Ser. No. 11 / 285,096, filed on Nov. 22, 2005, entitled “Formed Metal Core Sandwich Structure and Method and System for Making Same” and the disclosures of which are herein incorporated by reference in their entirety.BACKGROUND OF THE INVENTION [0002] 1. Technical Field [0003] The present invention relates to metal sandwich sheet structures and, more particularly, to formable metal core sandwich sheet structures and methods and systems for manufacturing same. [0004] 2. Description of Related Art [0005] Metal core sandwich structures are known in the art. For example, U.S. Pat. No. 3,525,663 to Hale and U.S. Pat. No. 4,035,536 to Morrison both disclose metal sandwich structures having a formed metal core brazed to two outer metal sheets. However, it is believed that the structures disclosed by Hale and Morrison, and other similar conventional formed metal core sandwich s...

AI Technical Summary

Benefits of technology

"The invention is an improved metal sandwich sheet structure that can be easily formed into complex shapes while maintaining its structural integrity. It is made up of a formed metal core that is brazed or bonded to two outer flat metal sheets. The metal core is made of a lightweight, stiffer sheet metal that can be easily formable into curved structures. The resulting sandwich structure is stronger and more durable than traditional honeycomb core sandwich structures, while being easier and more economical to manufacture. The method of producing the metal core sandwich structure includes providing a formed metal core that is easily formable into curved structures, rolling or pressing the metal core sheet into a corrugated shape, and forming micro-abrasions or indentations on the bonding lands to improve the brazing joints. The resulting sandwich structure is well-suited for various applications where formability and structural integrity are important. The invention also provides an apparatus for electro-tacking the formed core to the outer metal sheets prior to brazing. The cell shapes and geometries, as well as different cell sizes, can be designed to provide desired formability, stiffness, and crush characteristics."

Problems solved by technology

However, it is believed that the structures disclosed by Hale and Morrison, and other similar conventional formed metal core sandwich structures, cannot be easily formed into compound curves and other complex shapes without delaminating, wrinkling and / or otherwise losing its structural integrity.

Therefore, prior metal core sandwich structures are not well-suited for applications that require formation of compound curves, for example, without delaminating or wrinkling during the forming process.

Although this honeycomb core sandwich structure provides improved formability when compared to other metal core sandwich structures, it is relatively expensive to manufacture and, therefore, not well-suited for many commercial, cost-sensitive applications (e.g., automobile bodies).

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