Desenvolvimento de um sistema de estereolitografia termica em tres dimensões na construção de prototipos com a aplicação do laser de CO2

AUTOR(ES)

Andre Luiz Jardini Munhoz

DATA DE PUBLICAÇÃO

2001

RESUMO

We present in this work the use of infrared laser radiation to anchieve localized curing in thennosensitive polymers. In stereolithography the objective is to cure a localized region in a material by precisely confining the laser energy to the area that is to be cured. Industry already employs high-power ultraviolet laser radiation (HeCd laser @ 0,352 ~m) to fabricate three dimensional structures. In our experiments, we have focused the beam from a infrared radiation (C02 laser @ 10,6 J.1IIl) onto a sample composed of epoxy resin, diethylene triamine (curing agents) and silica powder (filler). Such resins typically cure, or solidify, when heated to moderately high temperature and our results show that we can confine the heating of the material, and, therefore, its curing, in all three dimensions. U sing a differential scanning calorimetry (DSC) we were able to determine reaction rates as a function of the temperature as well as the enthalpy involved in the phase transition and the activation energy of the curing process. A physical theoretical model is applied to control the parameters which influence the confinement of the curing in the" irradiated bulk. A numerical model is applied too, to model the heat flow in our sample as a result of infrared laser radiation through the resolution of the heat conduction equation dependent on time in cylindrical co-ordinates of the Ansy s program. The results allow us to predict the curing behavior of the sample as a function of laser irradiation conditions, and we find good agreement with our preliminary experimental observatories. Prototypes has been constructed layer by layer and experimental results of the production of solid layers of thickness 10-1-10-2 mm in two and three dimensions are presented

ASSUNTO(S)

lasers de dioxido de carbono resinas epoxi polimeros

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