Carreau-Yasuda Model

Mathematical Equation

Mathematical constitutive equations describe the non-Newtonian shear thinning behavior of polymers during the high-pressure stages of circuit board lamination. The carreau-yasuda model specifically maps how resin viscosity drops under increasing shear rates until reaching a lower limiting value. It accounts for the transition region between the zero-shear plateau and the power-law regime.

Flow Prediction

Software simulations utilize these parameters to predict how prepreg resin fills narrow gaps between copper traces during the lamination process. This specific model allows engineers to adjust the transition parameter and the power law index to match the behavior of specialized high-temperature resins. Accurate modelling prevents the formation of voids or thin spots during the press cycle.

The model provides a smooth transition between the zero-shear viscosity and the shear-thinning region, which is essential for capturing the flow behavior during the initial ramp-up of the lamination press. Without this level of detail, the simulation might overestimate the flow rate and lead to incorrect pressure settings.

Lamination Control

Rheological testing provides the empirical data required to fit the curve to a specific material batch. Variations in the relaxation time constant within the carreau-yasuda model indicate changes in polymer chain length or branching. Consistent curve fitting ensures that the lamination press operates within the optimal rheological window for the entire production run.

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Planar Permeability Tensor IPC-6012 Class 3 Prepreg Rheology

Non Newtonian Squeeze Flow Dynamics and Anisotropic Glass Weave Permeability under Non Isothermal Lamination Conditions

Non-isothermal squeeze flow and anisotropic permeability dictate prepreg filling, requiring precise press ramps to prevent dielectric micro-voiding.

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Shear Thinning Castro-Macosko Chemorheology Dynamic Viscosity

Dynamic Rheological Characterization of Ultra-Thin Thermoset Prepregs under High Shear Rate Multi-Stage Lamination

High shear rate squeeze flow during multi-stage lamination induces non-Newtonian thinning in ultra-thin prepregs, requiring precise pressure step timing to prevent microvia voiding and trace displacement.

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IPC-6012 Class 3 Shear Rate Dependence Microsectioning Verification

Modeling Slip Velocity and Pressure Gradients across Smooth Copper Foils

Modelling slip velocity and pressure gradients across smooth copper foils prevents resin starvation and locks dielectric thickness tolerances during lamination.

Blue nitrile gloves lower a black printed circuit board into a clear solvent bath among brushes tweezers and test probes.

Capillary Rheometry Panel Yield Gelation Point

Modeling Viscoelastic Boundary Layer Slip and Capillary Pressure Effects during High-Density Printed Circuit Board Lamination Cycles

Viscoelastic boundary slip and capillary pressure dictate microvia filling and trace stability during high-density circuit board lamination.

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1078 Prepreg Scanning Acoustic Microscopy PCB Stackup Yield

Non-Newtonian Flow Dynamics in Thin Prepreg Dielectric Micro-Channels

Non-Newtonian resin flow inside thin prepreg micro-channels governs void formation, trace displacement, and dielectric thickness stability during high-pressure lamination.