{"id":7060732,"date":"2026-09-19T03:59:07","date_gmt":"2026-09-19T03:59:07","guid":{"rendered":"https:\/\/som2nypost.com\/airbus\/bjorns-corner-aircraft-structures-part-19-liquid-composite-molding\/"},"modified":"2026-09-19T03:59:07","modified_gmt":"2026-09-19T03:59:07","slug":"bjorns-corner-aircraft-structures-part-19-liquid-composite-molding","status":"publish","type":"post","link":"https:\/\/som2nypost.com\/?p=7060732","title":{"rendered":"Bjorn’s Corner: Aircraft Structures Part 19. Liquid Composite Molding"},"content":{"rendered":"


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By Bjorn Fehrm \u2022 Aerospace Analyst\u00a0<\/strong><\/p>\n

September 18, 2026<\/strong><\/p>\n

Last week we looked at dry fiber layup methods that use a binder to tack fabrics or the tape in an AFP\/ATL system to the previous ply, creating a porous but rigid fiber preform. The binder is a heat-sensitive plastic that allows the generated preform to be handled and even reshaped if reheated.<\/p>\n

Once the preform is made, epoxy resin infusion can be done in three ways, grouped under the label Liquid Composite Molding. The first, called Resin Transfer Molding (RTM), is shown in Figure 1.<\/p>\n

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Figure 1. The Resin Transfer Molding (RTM) method. Photo credit: Hexcel.<\/strong><\/p>\n<\/div>\n

RTM<\/strong><\/h5>\n

The first method, Resin Transfer Molding (RTM), requires a closed mold. The preform that will fit in the closed mold can either be made in the mold, which would mostly be a manual layup of dry fabric, or be produced external to the mold, like for the CFM LEAP fan blade preform we showed in Part 17.<\/p>\n

A closed mold is necessary because heated resin (to reduce viscosity) is injected under pressure, forcing it through the dry preform to fully wet out the fibers. The mold is then heated to the resin\u2019s curing temperature.<\/p>\n

A closed mold is expensive but brings several advantages:<\/p>\n