Quantifying Shear Degradation and Fiber Breakdown in Mold Tooling
Quantifying shear rates and gate geometry limits prevents fiber length attrition, tool surface erosion, and mechanical strength loss in molded composite parts.
Polymer Rheology
Meaning
Study of the flow and deformation of polymer materials under varying conditions of temperature and pressure. Such polymer rheology provides the data needed to understand how a molten resin will behave during the high speed manufacturing of electronic enclosures. This field focuses on the relationship between shear rate, viscosity and the molecular structure of the plastic.
It is essential for predicting how fillers like glass fibers will align within the part during the injection molding process.
Viscosity Analysis
Measurement of the resistance to flow helps in selecting the correct material for thin walled designs. Lower viscosity resins are preferred for complex smartphone housings where the melt must travel through narrow channels. When polymer rheology is applied to a new project, it allows engineers to simulate the filling process before the mold is even built.
This simulation reduces the risk of defects like weld lines or air traps that can weaken the finished product.
Thermal Sensitivity
Behavior of the melt changes significantly as the temperature rises or falls within the processing equipment. Maintaining a stable temperature is necessary to prevent the polymer from becoming too thin or too thick for consistent molding. Because polymer rheology also considers the cooling phase, it helps in predicting the final shrinkage and warpage of the molded assembly.
Molecular Weight
Distribution of polymer chain lengths influences the mechanical properties and processability of the material.