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Original Date: 05/08/1995
Revision Date: 01/18/2007
Best Practice : Low Cost Composite Tooling
With the Department of Defense (DOD) purchasing fewer items, McDonnell Douglas Aerospace (MDA)-St. Louis started a program aimed at reducing the cost of producing composite curing tools. The cost of tooling to cure composite parts in a harsh autoclave environment has traditionally been high. However, in the past this cost could be spread across relatively large production volumes making the impact on unit cost less significant.
Curing tools are normally made from steel, aluminum, or electro-formed nickel to withstand the heat and pressure of an autoclave. These tools are expensive, have long lead times, are size limited, and require intermediate tooling. High temperature composite tooling is one alternative to these metallic tools; however, it has several drawbacks including durability problems, long lead times, and a requirement for intermediate tooling.
To solve these problems, MDA-St. Louis developed a new composite curing tool manufacturing process using arc- sprayed metal. This process utilizes a low-cost tooling form over which atomized molten metal is sprayed to form a thin metallic layer (Figure 2-12). This layer can then be removed from the original form and backed with a low-cost support structure (such as sprayed chopped fiber/resin) to add strength. The result is a low-cost, short lead time, high durability composite curing tool.
A tool has been manufactured in this manner for the AV-8B aircraft fuselage side panel. This tool was made for 34% less cost than the original electro-formed nickel production tool. MDA-St. Louis is now preparing to manufacture the first flyaway production side panel on the arc-sprayed tool.
Figure 2-12. ARC Sprayed Tool Fabrication Technology
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