Vol4 num4-21 Molds manufactured with 3D printing for UV curing using Light-RTM

Abstract

Ultraviolet (UV) curing is a competitive process both in terms of cycle time and energy consumption. However, it is limited to open mold processes where the material can be irradiated directly with UV light. There is a variant of RTM, Light-RTM, in which the flexible semi-mold can be manufactured with transparent/translucent materials and in small thicknesses. In the present work the feasibility of performing the semi-mold by stereolithography (SLA) has been studied. The photocurable resin selected for SLA was the high temperature resin from FormLabs. First, the UV light transmission has been characterized according to the thickness of the semi-mold wall, in which the mold thickness has been determined in 3 mm. The ageing process has also been analysed, characterising the variation of the transmitted spectrum as a function of the irradiation time for a 3 mm thick plate, where a loss of light transmission of approximately 13 % has been observed for 15 minutes of exposure time. Finally, a semi-mold has been manufactured for the manufacture by Light-RTM of a 150 mm × 40 mm × 2 mm flat plate. During the process, there were no problems of vacuum loss and the intensity of UV light that passes through the semi-mold allows curing the photocurable matrix of the composite material.