Guest Post by Huan Lee, Lambient Technologies Let’s look at the cure of carbon fiber reinforced prepreg (CFRP), which is challenging because of the conductive fabric. Use of a filter allows resin to flow to a dielectric/conductivity sensor yet prevents carbon fibers from short circuiting the measurement. In this post I’ll present data from a single batch of CFRP, tested for ... [Click to Continue...]

Guest Post by Huan Lee, Lambient Technologies Let’s look at the cure of Sheet Molding Compound (SMC) by measuring ion viscosity and using Critical Points, which I discussed earlier, to characterize the resulting curve. Bulk Molding Compound (BMC) is the generally the same material as SMC but in bulk form, so the results apply to BMC as well. As I wrote in my last post, ... [Click to Continue...]

Guest Post by Huan Lee, Lambient Technologies Dielectric cure monitors measure the dielectric properties of material at a single frequency or across a range of frequencies, selectively revealing the influence of mobile ions and dipole rotation. As we saw in previous posts, ion viscosity is frequency independent resistivity (rDC) and is often proportional to mechanical ... [Click to Continue...]

Guest Post by Huan Lee, Lambient Technologies The ion viscosity of a thermoset is the frequency independent resistivity (rDC). In many cases ion viscosity is proportional to mechanical viscosity before gelation and proportional to modulus after gelation, making ion viscosity a useful probe of material state through the entire cure. Figure 1 shows the behavior of a ... [Click to Continue...]