Situ Frequency Dependent Dielectric Sensing of Cure

5 Monitoring Cure in Multiple Time Temperature Processing Cycles. 145 

In situ frequency dependent electromagnetic-impedence measurements provide a sensitive, convenient, automated technique to monitor the changes in macroscopic cure processing properties and the advancement of the reaction in situ in the fabrication tool. This chapter discusses the instrumentation, theory, and several applications of the techniques, including isothermal cure, complex time—temperature cure, resin film infusion, thick laminates, and smart, automated control of the cure process. 

Second, by actually monitoring the state of the material, it is possible to control the fabrication process by data rather than a procedure, such as a set time temperature sequence. This means one can have a self-correcting, automated, intelligent cure process that can adapt to variations in material age, fabric permeability, tool heat transfer characteristics, and the like. 

in situ sensing is needed to verify the veracity and logic of a model s predictions or an operator s reasoning. Making a composite part that passes mechanical tests does not verify that the modeling equations or operator thinking are correct and can be trusted to make predictions. 

In summary, dielectric sensing provides valuable insight in observing the state of the resin during the process, verifying and reducing the time in developing a cure process, as well as 

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In Situ Frequency Dependent Dielectric Sensing of Cure... 

Frequency dependent dielectric measurements made over many decades of frequency (Hz to MHz) provide a sensitive, convenient means for characterising processing properties of thermosets and thermoplastics [882]. DIES contributes to the understanding of the dynamics of complex solid polymer systems such as blends, of polymer solutions, and of polymerisation and curing or drying reactions. On-line in situ dielectric sensing is applied in monitoring the polymerisation step in the production of... 

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