Subframe for a motor vehicle and method for producing a subframe

A method for producing a subframe comprising an upper shell and a lower shell made from a fiber-reinforced plastic and a rib structure for stiffening the upper shell, comprising the following method steps:

• providing an upper shell made from a metallic material,
• providing a stack of plies made from a fiber-reinforced plastic having a thermoplastic matrix, wherein a first ply comprises at least one sheet of a first type containing fibers in the form of woven fibers and/or non-crimp fibers and/or short fibers and a second ply comprises at least one sheet of a second type containing fibers in the form of short fibers,
• heating the stack to a temperature T higher than the melting temperature of the thermoplastic matrix before, during or after the introduction of the stack into an impact extrusion tool,
• forming the stack in an impact extrusion process, with the result that the first ply is formed into the lower shell and the second ply is formed into the rib structure, wherein the lower shell and the rib structure are formed integrally,
• removing the lower shell and the rib structure from the mold,
• joining the upper shell, the lower shell and the rib structure to form the subframe.