Tooling Materials and Their Effect on Surface Thermal Gradients
The composites industry employs a wide variety of tooling strategies. Generally speaking, thermal management challenges are not considered in the design of the tool until the first thermal cycle of the tool. Conventional design practices rely on material selection and geometry sizing as the first steps for controlling spring-in and structural stiffness. These parameters are found to have a significant effect upon the heating characteristics of the tool. To identify the effect of different tooling materials on thermal variation of the tool surface, a combined experimental and numerical approach is employed in this study. Three identical geometry tools made of carbon fiber reinforced polymer (CFRP), aluminum, and invar are compared. Using infrared (IR) thermography an investigation of the surface temperature distribution during heat-up is conducted. Thermal simulation is then used to further study the relationship between heating rates and surface temperature uniformity. Results show that, as expected, tooling material diffusivity plays a significant role in controlling the in-plane thermal gradients. Furthermore, a number of geometric features, in particular the tooling sub-structure, are found to potentially also affect the thermal gradients.
Author: John Park
Conference: SAMPE Seattle 2017