ANALYSIS OF THE INTEGRATED PRODUCTION OF SANDWICH PARTS MADE OF PU FOAM CORE AND CONTINUOUS FIBER-REINFORCED TOP LAYERS IN A COMBINED SPRAY IMPREGNATION AND WET PRESSING PROCESS

摘要

Composite parts with high fiber volume contents (≥ 50%) and polyurethane (PU) matrix gain increasing relevance for the production of structural parts in short cycle times. Due to their excellent stiffness to weight ratio, sandwich structures are applied in order to maximize the lightweight potential. An important disadvantage of existing technologies is the separate production and forming of the foam cores or honeycomb structures, which have to be integrated into the subsequent mold or adhesively bonded to the separately produced fiber-reinforced top layers. To overcome this disadvantage, a process chain consisting of a PU-spray impregnation of continuous fiber reinforcements in combination with a wet pressing process has been developed. This paper describes the results of a process analysis for integrating the foaming process of the core into the pressing process. The process parameters (e.g. PU foam quantity) have a significant influence on the part quality, so that optimum process parameters for the developed process chain are derived.