Infrared heating stage simulation of semi-transparent media (PET) using ray tracing method

Abstract

Stretch blow molding or thermoforming processes includes an infrared heating stage of the thermoplastic preform by infrared heaters. The knowledge of the temperature distribution on the surface and through the thickness of the preform is important to make good prediction of thickness and properties of the manufactured parts. Currently in industry, the fitting of the process parameters is given by experience and is expensive. Our objective is to provide tools that are able to simulate the heat transfers between infrared heaters and preforms in order to reduce the fitting cost and to control the qualities of the end products. The optical method called "ray tracing" is used to simulate the radiative transfer. First, we compare the ray tracing method with the view factor method on a simple example: the heating of a square sheet by one infrared lamp. Then, we perform 3D heating stage simulations and compare with experiments. The ray tracing method allows to compute a source term in the transient heat balance equation. Then commercial finite element method softwares can be used to solve the heat balance equation.

In-situ infrared thermography measurements to master transmission laser welding process parameters of PEKK

“…To estimate the impact of temperature variation due to the emissivity, a variability test was undertaken. The emissivity was set up as 0.91 for the semitransparent PEKK and 0.96 for the opaque one; these values are in agreement with previous studies [12,23] . For our variability test, the emissivity factor varies from 0.8 to 0.98.…”

Laser transmission welding as an assembling process for high temperature electronic packaging

“…Infrared measurements are sensitive to the emissivity of the samples. The emissivity was set up as 0.91 for the semitransparent material and 0.96 for the opaque material; these values are in agreement with previous studies [12]. To estimate the impact of temperature variation due to the emissivity, a variability test was undertaken upon the samples.…”

Simulation of the stretch blow moulding process: from the modelling of the microstructure evolution to the end-use elastic properties of polyethylene terephthalate bottles

“…This difference could be explained by many reasons: mode of deformation, strain rate, cooling rate, contact conditions, injection conditions of the preform for example. A better description of the initial temperature conditions of the stretch blow moulding process and the use of a more realistic blowing pressure evolution, as presented in Menary et al [40] or Cosson et al [41], for example, would also improve the predictions.…”