Heat flux canals (HFC) technique: An alternative to cool down stereolithography moulds

Abstract

The design of injection mould inserts obtained by stereolithography (SL) has various recommendations that are based on experimental work done by researchers over the last decade. There are no final conclusions about the best cooling technique for SL inserts. Moreover, no criteria are presented concerning structural and thermal designs based on stress-strain analysis, although a number of researchers consider ejection forces as the main failure effect of the SL tool. This work presents an alternative technique to cool down SL inserts, based on heat flux canals that are strategically positioned on hot areas along the cavity walls. Using this approach it is possible to keep direct contact between the back metal filling of the stereolithography insert and the injected thermoplastic material. This paper shows the results of aspects such as thermal evaluation in a FEM analysis, where the heat flux canals, solid SL moulds and the traditional Direct AIM™ process performances have been compared. The results indicate that this evolution of the Direct AIM™ process may improve the average life of SL inserts while keeping the traditional one-week development for the tool.