Application and thermal field analysis of multilayer thermal insulation in in-situ forming process of thermoplastic composites

The carbon fiber reinforced polyetheretherketone (CF/PEEK) composite material can achieve high efficiency and integrated assembly molding through in-situ consolidation, suitable for the preparation of high-speed motor rotor sleeves. However, the high forming temperature of CF/PEEK may cause demagnetization of the magnet once the temperature exceeds the curie temperature of the magnet. To address the insulation issues during the sleeve forming process, this study proposes using metal-containing multilayer thermal insulations (MTI) to prepare the insulation layer, which takes advantage of the heat transfer within the metal layer to achieve thickness-wise insulation. A finite element heat field model is established to analyze the effect of material thermal properties, layer structure, and thermal field conditions on the thermal insulation effect. The response surface methodology analysis shows that metal materials with high thermal conductivity and high volume-specific heat have better insulation performance. The highest temperature of the bottom surface of the copper-containing MTI is only 64% of that of the glass fiber reinforced polypropylene (GF/PP) layer MTI. Analysis of the layer structure shows that the closer the metal layer is to the heat source, the better the insulation effect. The sensitivity analysis of the thermal field conditions shows that the thermal conductivity of the inner layer has a greater impact on the insulation effect. Subsequently, the MTI containing copper was optimized in response to the specific insulation requirements of the motor rotor sleeve, providing a reference for the application of in-situ consolidated integrated assembly molding in thermoplastic composites.