Optical thermal model for LED heating in thermoset-automated fiber placement

Abstract

Control of material temperature distribution and governing phenomena during automated fiber placement is an important factor. Numerical modeling of the radiative heat transfer for a newly presented LED-based heating unit is developed and analyzed in theory. An optical model allows taking into account the radiative energy output of every individual LED. By adjusting the electrical input to the multiple LED arrays on the heating unit, the irradiance distribution on the substrate's surface can be controlled. To investigate the capability to adjust the surface temperature distribution resulting from this feature, thermal models for two and three dimensions are developed and employed for the calculated irradiance distributions. The resulting temperature distributions show that temperature gradients can be avoided or created, depending on the input to the heating unit. The results from the two models are compared and a method to select an appropriate model in general is proposed.

Prepreg tack: A review of mechanisms, measurement, and manufacturing implication

“…[109] This may contribute to the fact that efforts have been put into the heat transfer simulation to predict temperature distribution in thermoset lay-up processes. [110][111][112][113] Although considered a matter of process parameter adjustment, control of temperature strongly governs both environmental and material influences as well. Hence, prepreg tack as a function of temperature has been targeted by several experimental studies with most of them revealing a significant correlation.…”

Picosecond pulsed laser illumination: an ultimate solution for photonic versus thermal processes’ contest in SOI photo-activated modulator

“…With time, textbooks addressed and treated generation and recombination processes of carriers due to thermal and photonic activation 2 . In addition, more specific models for heat generation and transport as well as for coupling of optical, electrical and thermal models were conducted for several types of devices such as transistors 3 , 4 , resonators 5 , solar cells 6 , light emitting devices (LED) 7 , organic light emitting devices (OLED) 8 , Vertical Cavity Surface-Emitting Lasers (VCSEL) 9 , lasers 10 , and fiber optics 11 . When compared to above specific devices, for which relevant models were developed accordingly, a new analysis was now required for the Silicon-On-Insulator Photo-Activated-Modulator (SOIPAM) device, sharing a V-groove aperture for illumination trigger, and enabling several activation mechanisms, as described below.…”

Ply-by-ply inline thermography inspection for thermoplastic automated tape layup

“…As the tapes cool down, consolidation follows [34]. Based on the material and processing requirements, a variety of heat sources are employed for ATL processes like hot gas torch [25], laser [35] and LED heating [36] among others. The present work utilizes, a radiation based pulsed light energy system, humm3 as the main heat source.…”